ptARgenOM-A Flexible Vector For CRISPR/CAS9 Nonviral Delivery

Viral-mediated delivery of the CRISPR-Cas9 system is one the most commonly used techniques to modify the genome of a cell, with the aim of analyzing the function of the targeted gene product. While these approaches are rather straightforward for membrane-bound proteins, they can be laborious for intracellular proteins, given that selection of full knockout (KO) cells often requires the amplification of single-cell clones. Moreover, viral-mediated delivery systems, besides the Cas9 and gRNA, lead to the integration of unwanted genetic material, such as antibiotic resistance genes, introducing experimental biases. Here, an alternative non-viral delivery approach is presented for CRISPR/Cas9, allowing efficient and flexible selection of KO polyclonal cells. This all-in-one mammalian CRISPR-Cas9 expression vector, ptARgenOM, encodes the gRNA and the Cas9 linked to a ribosomal skipping peptide sequence followed by the enhanced green fluorescent protein and the puromycin N-acetyltransferase, allowing for transient, expression-dependent selection and enrichment of isogenic KO cells. After evaluation using more than 12 distinct targets in 6 cell lines, ptARgenOM is found to be efficient in producing KO cells, reducing the time required to obtain a polyclonal isogenic cell line by 4-6 folds. Altogether ptARgenOM provides a simple, fast, and cost-effective delivery tool for genome editing.

Endovascular renal sympathetic denervation to improve heart failure with reduced ejection fraction: the IMPROVE-HF-I study

Introduction

The aim of the present study was to assess the safety and efficacy of renal sympathetic denervation (RDN) in patients with heart failure with reduced ejection fraction (HFrEF).

Methods

We randomly assigned 50 patients with a left ventricular ejection fraction (LVEF) ≤ 35% and NYHA class ≥ II, in a 1:1 ratio, to either RDN and optimal medical therapy (OMT) or OMT alone. The primary safety endpoint was the occurrence of a combined endpoint of cardiovascular death, rehospitalisation for heart failure, and acute kidney injury at 6 months. The primary efficacy endpoint was the change in iodine-123 meta-iodobenzylguanidine (¹²³I‑MIBG) heart-to-mediastinum ratio (HMR) at 6 months.

Results

Mean age was 60 ± 9 years, 86% was male and mean LVEF was 33 ± 8%. At 6 months, the primary safety endpoint occurred in 8.3% vs 8.0% in the RDN and OMT groups, respectively (p = 0.97). At 6 months, the mean change in late HMR was −0.02 (95% CI: −0.08 to 0.12) in the RDN group, versus −0.02 (95% CI: −0.09 to 0.12) in the OMT group (p = 0.95) whereas the mean change in washout rate was 2.34 (95% CI: −6.35 to 1.67) in the RDN group versus −2.59 (95% CI: −1.61 to 6.79) in the OMT group (p-value 0.09).

Conclusion

RDN with the Vessix system in patients with HFrEF was safe, but did not result in significant changes in cardiac sympathetic nerve activity at 6 months as measured using ¹²³I‑MIBG.

Supplementary Information

The online version of this article (10.1007/s12471-021-01633-z) contains supplementary material, which is available to authorized users.

Sex-specific temporal evolution of circulating biomarkers in patients with chronic heart failure with reduced ejection fraction

BACKGROUND

We aimed to assess differences in clinical characteristics, prognosis, and the temporal evolution of circulating biomarkers in male and female patients with HFrEF.

METHODS

We included 250 patients (66 women) with chronic heart failure (CHF) between 2011 and 2013 and performed trimonthly blood sampling during a median follow-up of 2.2 years [median (IQR) of 8 (5-10) urine and 9 (5-10) plasma samples per patient]. After completion of follow-up we measured 8 biomarkers. The primary endpoint (PE) was the composite of cardiac death, cardiac transplantation, left ventricular assist device implantation, and hospitalization due to acute or worsened CHF. Joint models were used to determine whether there were differences in the temporal patterns of the biomarkers between men and women as the PE approached.

RESULTS

A total of 66 patients reached the PE of which 52 (78.8%) were male and 14 (21.2%) were female. The temporal patterns of all studied biomarkers were associated with the PE, and overall showed disadvantageous changes as the PE approached. For NT-proBNP, HsTnT, and CRP, women showed higher levels over the entire follow-up duration and concomitant numerically higher hazard ratios [NT-proBNP: women: HR(95%CI) 7.57 (3.17-21.93), men: HR(95%CI) 3.14 (2.09-4.79), p for interaction = 0.104, HsTnT: women: HR(95%CI) 6.38 (2.18-22.46), men: HR(95%CI) 4.91 (2.58-9.39), p for interaction = 0.704, CRP: women: HR(95%CI) 7.48 (3.43-19.53), men: HR(95%CI) 3.29 [2.27-5.44], p for interaction = 0.106). In contrast, temporal patterns of glomerular and tubular renal markers showed similar associations with the PE in men and women.

CONCLUSION

Although interaction terms are not statistically significant, the associations of temporal patterns of NT-proBNP, HsTnT, and CRP appear more outspoken in women than in men with HFrEF, whereas associations seem similar for temporal patterns of creatinine, eGFR, Cystatin C, KIM-1 and NAG. Larger studies are needed to confirm these potential sex differences.

Grafting TRAIL through Either Amino or Carboxylic Groups onto Maghemite Nanoparticles: Influence on Pro-Apoptotic Efficiency

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a member of the TNF cytokine superfamily. TRAIL is able to induce apoptosis through engagement of its death receptors DR4 and DR5 in a wide variety of tumor cells while sparing vital normal cells. This makes it a promising agent for cancer therapy. Here, we present two different ways of covalently grafting TRAIL onto maghemite nanoparticles (NPs): (a) by using carboxylic acid groups of the protein to graft it onto maghemite NPs previously functionalized with amino groups, and (b) by using the amino functions of the protein to graft it onto NPs functionalized with carboxylic acid groups. The two resulting nanovectors, NH-TRAIL@NPs-CO and CO-TRAIL@NPs-NH, were thoroughly characterized. Biological studies performed on human breast and lung carcinoma cells (MDA-MB-231 and H1703 cell lines) established these nanovectors are potential agents for cancer therapy. The pro-apoptotic effect is somewhat greater for CO-TRAIL@NPs-NH than NH-TRAIL@NPs-CO, as evidenced by viability studies and apoptosis analysis. A computational study indicated that regardless of whether TRAIL is attached to NPs through an acid or an amino group, DR4 recognition is not affected in either case.

P6319CT derived fractional flow reserve (FFRct) for functional coronary artery evaluation in the follow-up of patients after heart transplantation

Background

Cardiac allograft vasculopathy (CAV) remains a leading cause of morbidity and mortality after heart transplantation. Annual screening is recommended to improve risk stratification and early treatment of CAV and is often performed with invasive coronary angiography (ICA). Coronary computed tomography angiography (CCTA) with CCTA-derived fractional flow reserve (FFRct) might be a non-invasive alternative to ICA for the surveillance of CAV providing both anatomical and functional information.

Purpose

To describe our initial results with CCTA and FFRct for detection of CAV in a cohort of heart transplant patients.

Methods

Heart transplant patients who underwent CCTA with FFRct as part of routine annual assessment for CAV were enrolled in a prospective registry from February 2018 to February 2019 in a single center. The most recently known CAV score (0–3) based on invasive angio and single photon emission computed tomography (SPECT) before CCTA was recorded. CCTA image quality was scored as non-diagnostic, moderate, good or excellent. FFRct analysis was performed off-site by a commercial company. For each coronary stenosis >30%, an FFRCTvalue distal to the stenosis was measured. For the RCA, LAD and CX without a stenosis, the FFRct value in the most distal location in the vessel was recorded. CAV classification was rescored based on CCTA. Demographics, additional diagnostic tests, and treatment plans were evaluated including major adverse events (MACE) during 90-day follow-up.

Results

65 patients (56 (39–65) years (median/ 25th–75thpercentile), 40% women) that were 11 (7–16) years after transplantation were included. The most recent CAV score was 0 in 52 patients (80%) and 1 or 2 in 13 patients. CCTA image quality was good or excellent in 59 (91%) patients. CCTA reclassified CAV scores in 32 (49%) patients to 33 patients with CAV 0, 18 patients with CAV 1, 9 patients with CAV 2 and 5 patients with CAV 3. In 17 patients (26%) at least one stenosis with FFRct ≤0.80 was detected including 11 patients with single vessel disease, 5 with two-vessel disease and one with three-vessel disease. In the 48 patients without a focal stenosis, mean distal FFRct values were 0.88 (0.86–0.91), 0.87 (0.85–0.90) and 0.90 (0.86–0.91) at less than 10, 10–15 or more than 15 years after transplantation, respectively (p=0.457). Additional tests were performed in 10 (15%) patients (1 SPECT and 10 invasive coronary angiographies), which resulted in revascularization by PCI in 6 (9%) patients. No MACE occurred during 90-day follow-up.

Conclusion

CCTA with FFRct can be successfully performed in heart transplant patients, detects patients with significant coronary stenosis and CCTA leads to substantial reclassification of CAV grades.

Acknowledgement/Funding

FFRct analysis was performed as part of the ADVANCE registry which is supported by Heartflow Inc.

P1675Evolution of lactate dehydrogenase levels in patients with HeartMate II, HeartWare and HeartMate 3 left ventricular assist devices during first-year follow-up

Background

Lactate dehydrogenase (LDH) is considered as a biomarker of thrombotic events in patients receiving a left ventricular assist device (LVAD).

Purpose

This study aimed to investigate the evolution of LDH levels over time between patients supported with a HeartMate II (HMII), HeartMate 3 (HM3) or HeartWare (HVAD) LVAD during their first-year post implantation.

Methods

We analyzed in this multi-center retrospective study, all patients with HMII, HM3 and HVAD LVAD implanted between December 2006 and April 2017. Patients were classified into three groups based on their device type. Loess splines over time were used to depict the repeated measurements of LDH.

Results

In total, 134 patients received an LVAD (77% male, mean age 55 [46–61]), of whom 64 (48%) were HMII, 22 (16%) HM3 and 48 (36%) were HVAD. Loess splines over time indicate that there could be a considerable difference between evolution of LDH (Figure). During the first-year follow-up, 3 (5%) patients had a confirmed and 10 (16%) patients had a suspected pump thrombosis in the HMII group. For the HVAD, there were 6 (13%) patients with confirmed thrombosis and 1 (2%) case of suspected thrombosis, whereas none of the patients in the HM3 group experienced a suspected or confirmed pump thrombosis (p=0.01). The 1-year overall survival rate for HM II, HM3 and HVAD was 84%, 86% and 72% respectively (p=0.311). The overall stroke-free rate at one year was: 89%, 77% and 91% for HMII, HVAD and HM3 respectively (p=0.15).

Means of observed LDH values over time

Conclusion

During the first-year post LVAD implantation, there appear to be different evolutions of LDH levels over time in HMII device patients compared to HVAD or HM3 device patients. Given differences in baseline hemolysis levels between devices, currently used LDH thresholds for detection of impending pump thrombosis may be less sensitive and thus thresholds may be device specific.

P5421Prevalence of electromagnetic interference from left ventricular assist devices in patients with implantable cardioverter defibrillator/pacemakers

Background

Many patients eligible for left ventricular assist device (LVAD) therapy already have an implantable cardioverter defibrillator (ICD) and/or pacemaker (PM). However, electromagnetic interference (EMI) between the LVAD and ICD/PM devices could be cumbersome.

Purpose

The aim of this study was to investigate the prevalence of EMI between different types of ICD/PM in patients implanted with an LVAD.

Methods

Data was obtained through a retrospective electronic patient database analysis of all LVAD patients (including HeartMate II (HMII) and HeartMate 3 (HM3)), from our tertiary referral center, from December 2006 to February 2019. Device switches have also been taken into account due to elective replacement. Electromagnetic interference was defined as ICD/PM telemetry interference (i.e. the inability to interrogate ICD/PM)

Results

In total, 109 patients received an LVAD (mean age 52±12, 83% male), Of these, 86 (79%) patients had an ICD/PM at LVAD implantation. One patient with ICD/PM was excluded from further analysis because of missing follow-up data. Among the 85 patients (45 HM II and 40 HM3), 11 (13%) experienced EMI; 5 (11%) with a HM II and 6 (15%) with a HM3 (p=0.59). The implanted ICD/PM devices were from Medtronic (n=25), Abbott (n=23), Biotronik (n=18), Boston Scientific (n=18), and Microport (n=1). EMI with the HM II was present in St Jude/Abbott devices (type 1 Atlas, 1 Unify, 1 Fortify, and 2 Promote). In HM 3 LVAD patients, EMI was observed in Biotronik devices (1 Lumax, 1 Ilivia, 1 Ilesto, and 2 Iperia) and Medtronic (Claria).

Conclusion

In our cohort of HM II and HM 3 LVAD patients, at least one in seven patients experienced EMI from either the HM II or HM3 LVAD with the ICD/PM. Electromagnetic interference from HM II LVADs was mainly present in patients with St Jude/Abbott ICD/PM devices However, in the HM3 patients, EMI was mainly present in patients with Biotronik devices, which is not yet widely known!

P1644Personalized screening intervals for measurement of n-terminal pro-b-type natriuretic peptide improve efficiency of prognostication in patients with chronic heart failure

Background

Predefined screening intervals and target levels do not account for variations in temporal patterns of biomarkers between individuals, which may hamper their potential use for therapy guidance. Conversely, a personalized screening approach with screening intervals and target levels based on the evolution of biomarkers in individual patients may further improve risk assessment and therapy guidance.

Purpose

We hypothesize that personalized screening intervals for N-terminal pro-B-type natriuretic peptide (NT-proBNP) measurements in patients with chronic heart failure (CHF) maximize information gain on the individual patient's disease progression, while minimizing the number of necessary measurements. We aim to compare such personalized scheduling of NT-proBNP measurements to a predefined fixed scheduling approach.

Methods

In 263 CHF patients from the Bio-SHiFT study, NT-proBNP was measured trimonthly according to a prespecified, fixed schedule [median: 9 (IQR: 5–10) measurements per patient].The primary composite endpoint (PE) comprised cardiac death, cardiac transplantation, left ventricular assist device implantation or heart failure hospitalization, and occurred in 70 patients (26.6%). Using joint models for time-to-event and longitudinal data, we modelled the association between repeated NT-proBNP measurements and the PE. Using the fitted joint model, for each patient at each follow-up visit, we determined the optimal time point of the next NT-proBNP measurement based on the patient's individual risk profile and the maximum information gain on the patient's prognosis as assessed by the Kullback-Leibler divergence. Personalized scheduling was compared to fixed (trimonthly) scheduling by means of a realistic simulation study, based on a replica of the study population included in the Bio-SHiFT study. In this simulation study, we stopped monitoring NT-proBNP to potentially enable appropriate timely intervention if the cumulative risk of PE exceeded an arbitrary risk threshold of 7.5% within 3-months. We compared personalized scheduling with fixed scheduling in terms of capability of identification of high-risk intervals (whether timely intervention was enabled before occurrence of PE), number of measurements needed, and costs.

Results

Compared to fixed scheduling, personalized scheduling saved on average 2 measurements [personalized; median: 7 (IQR: 7–8) vs. fixed; 9 (IQR: 8–10) measurements], while the start of the time-window identified for therapeutic intervention to avoid the occurrence of PE was similar in both approaches [personalized; median: 6.6 (IQR: 4.5–11.3) vs. fixed; 6.3 (IQR: 4.2–10.3) months before occurrence of PE]. Costs saved were €165 per patient per year.

Figure 1

Conclusion

Personalized scheduling of NT-proBNP measurements in CHF patients shows similar prognostic performance as fixed scheduling, but requires fewer NT-proBNP measurements. This may improve efficiency of natriuretic guided therapy, if the latter were to be installed.

Acknowledgement/Funding

Funding for this study was provided by the Jaap Schouten Foundation and Erasmus MC Efficiency Research grant

TRAIL receptor gene editing unveils TRAIL-R1 as a master player of apoptosis induced by TRAIL and ER stress

TRAIL induces selective tumor cell death through TRAIL-R1 and TRAIL-R2. Despite the fact that these receptors share high structural homologies, induction of apoptosis upon ER stress, cell autonomous motility and invasion have solely been described to occur through TRAIL-R2. Using the TALEN gene-editing approach, we show that TRAIL-R1 can also induce apoptosis during unresolved unfolded protein response (UPR). Likewise, TRAIL-R1 was found to co-immunoprecipitate with FADD and caspase-8 during ER stress. Its deficiency conferred resistance to apoptosis induced by thaspigargin, tunicamycin or brefeldin A. Our data also demonstrate that tumor cell motility and invasion-induced by TRAIL-R2 is not cell autonomous but induced in a TRAIL-dependant manner. TRAIL-R1, on the other hand, is unable to trigger cell migration owing to its inability to induce an increase in calcium flux. Importantly, all the isogenic cell lines generated in this study revealed that apoptosis induced TRAIL is preferentially induced by TRAIL-R1. Taken together, our results provide novel insights into the physiological functions of TRAIL-R1 and TRAIL-R2 and suggest that targeting TRAIL-R1 for anticancer therapy is likely to be more appropriate owing to its lack of pro-motile signaling capability.

β cell membrane remodelling and procoagulant events occur in inflammation-driven insulin impairment: a GLP-1 receptor dependent and independent control

Inflammation and hyperglycaemia are associated with a prothrombotic state. Cell-derived microparticles (MPs) are the conveyors of active procoagulant tissue factor (TF) and circulate at high concentration in diabetic patients. Liraglutide, a glucagon-like peptide (GLP)-1 analogue, is known to promote insulin secretion and β-cell preservation. In this in vitro study, we examined the link between insulin impairment, procoagulant activity and plasma membrane remodelling, under inflammatory conditions. Rin-m5f β-cell function, TF activity mediated by MPs and their modulation by 1 μM liraglutide were examined in a cell cross-talk model. Methyl-β-cyclodextrine (MCD), a cholesterol depletor, was used to evaluate the involvement of raft on TF activity, MP shedding and insulin secretion as well as Soluble N-éthylmaleimide-sensitive-factor Attachment protein Receptor (SNARE)-dependent exocytosis. Cytokines induced a two-fold increase in TF activity at MP surface that was counteracted by liraglutide. Microparticles prompted TF activity on the target cells and a two-fold decrease in insulin secretion via protein kinase A (PKA) and p38 signalling, that was also abolished by liraglutide. Large lipid raft clusters were formed in response to cytokines and liraglutide or MCD-treated cells showed similar patterns. Cells pre-treated by saturating concentration of the GLP-1r antagonist exendin (9-39), showed a partial abolishment of the liraglutide-driven insulin secretion and liraglutide-decreased TF activity. Measurement of caspase 3 cleavage and MP shedding confirmed the contribution of GLP-1r-dependent and -independent pathways. Our results confirm an integrative β-cell response to GLP-1 that targets receptor-mediated signalling and membrane remodelling pointing at the coupling of insulin secretion and inflammation-driven procoagulant events.

Exocrine cell-derived microparticles in response to lipopolysaccharide promote endocrine dysfunction in cystic fibrosis

BACKGROUND

Diabetes in cystic fibrosis (CF) is a result of exocrine pancreas alteration followed by endocrine dysfunction at a later stage. Microparticles (MPs) are plasma membrane fragments shed from stimulated or damaged cells that act as cellular effectors. Our aim was to identify a new form of interaction between exocrine and endocrine pancreatic cells mediated by exocrine MPs, in the context of recurrent infection in CF.

METHODS

MPs from either human exocrine CFTRΔF508-mutated (CFPAC-1) cells or exocrine normal pancreatic (PANC-1) cells were collected after treatment by LPS from Pseudomonas aeruginosa and applied to rat endocrine normal insulin-secreting RIN-m5F cells. MP membrane integration in target cells was established by confocal microscopy and flow cytometry using PKH26 lipid probe. Apoptosis, lysosomal activity, insulin secretion were measured after 18 h. MP-mediated NF-κB activation was measured in HEK-Blue reporter cells by SEAP reporter gene system and in RIN-m5F cells by Western blot. In endocrine normal cells, CFTR inhibition was achieved using Inhibitor-172.

RESULTS

Compared to PANC-1, MPs from CFPAC-1 significantly reduced insulin secretion and lysosomal activity in RIN-m5F. MPs induced NF-κB activation by increasing the level of IκB phosphorylation. Moreover, the inhibition of NF-κB activation using specific inhibitors was associated with a restored insulin secretion. Interestingly, CFTR inhibition in normal RIN-m5F cells promoted apoptosis and decreased insulin secretion.

CONCLUSIONS

During recurrent infections associated with CF, exocrine MPs may contribute to endocrine cell dysfunction via NF-κB pathways. Membrane CFTR dysfunction is associated with decreased insulin secretion.

Disseminated intravascular coagulation and a negative D-dimer test

The diagnosis of disseminated intravascular coagulation (DIC) requires the presence of a fibrin-related marker. D-dimer is frequently used in clinical practice as a fibrin-related marker. We present a case of paraneoplastic DIC with a false-negative D-dimer test. Repeating the test using a different D-dimer assay as well as the measurement of other fibrinolysis markers confirmed the diagnosis of DIC.

Elevated capillary tube hematocrit reflects degradation of endothelial cell glycocalyx by oxidized LDL

Proteoglycans and plasma proteins bound to the endothelial cell glycocalyx are essential for vascular function, but at the same time, they lower capillary tube hematocrit by reducing capillary volume available to flowing blood. Because oxidized low-density lipoproteins (oxLDL) reduce the effective thickness of the glycocalyx (Vink H, Constantinescu AA, and Spaan JAE. Circulation 101: 1500-1502, 2000), we designed the present study to determine whether this is caused by pathological degradation of glycocalyx constituents or increased glycocalyx deformation by elevated shear forces of flowing blood. Capillaries from the right cremaster muscle of 24 hamsters were examined by using intravital microscopy after systemic administration of normal LDL (n = 4), moderate oxLDL (6-h oxidation with CuSO(4), n = 7), severe oxLDL (18-h oxidation, n = 5), and moderate oxLDL plus superoxide dismutase (SOD) and catalase (n = 8). Capillary tube hematocrit increased from 0.16 +/- 0.03 to 0.37 +/- 0.05 and from 0.15 +/- 0.01 to 0.31 +/- 0.03 after moderate oxLDL and severe oxLDL, respectively. These changes were paralleled by increases in red blood cell flux from 8.7 +/- 1.9 to 13.8 +/- 3 and from 10.7 +/- 2.1 to 16.3 +/- 3.2 cells/s after moderate oxLDL and severe oxLDL, respectively, in the absence of changes in anatomic capillary diameter. Red blood cell velocity, as a measure for the shear forces on the glycocalyx, was not affected by oxLDL, whereas tissue pretreatment with SOD and catalase completely abolished the effects of oxLDL on glycocalyx thickness, capillary hematocrit, and red blood cell flux. We conclude that elevation of capillary tube hematocrit by oxLDL reflects degradation of the endothelial glycocalyx by oxygen-derived free radicals.

Oxidized lipoproteins degrade the endothelial surface layer : implications for platelet-endothelial cell adhesion

BACKGROUND

Flowing erythrocytes and platelets are separated from the luminal endothelial cell (EC) surface by a 0.5-microm-wide space named the endothelial surface layer. We hypothesized that the disruption of the endothelial surface layer by oxidized low-density lipoproteins (Ox-LDL) contributes to atherogenic increases in vascular wall adhesiveness.

METHODS AND RESULTS

The hamster cremaster muscle preparation was used for intravital microscopic observation of the distance between erythrocytes and the capillary EC surface. Moderate Ox-LDL was prepared by exposing native LDL to CuSO(4) for 6 hours. The dimension of the EC surface layer averaged 0.6+/-0.1 microm during control situations, but a bolus intravenous injection of Ox-LDL (0.4 mg/100 g of body weight) transiently diminished the EC surface layer by 60% within 25 minutes, which correlated with a transient increase in the number of platelet-EC adhesions. Combined administration of superoxide dismutase and catalase completely blocked the effect of Ox-LDL on the dimension of the EC surface layer and inhibited platelet-EC adhesion.

CONCLUSIONS

Oxygen-derived free radicals mediate the disruption of the EC surface layer and increase vascular wall adhesiveness by Ox-LDL.