Targeting vascular inflammation represents a novel therapeutic approach to reduce complications of atherosclerosis. Neutralizing the pro-inflammatory cytokine interleukin-1β (IL-1β) using canakinumab, a monoclonal antibody, reduces the incidence of cardiovascular events in patients after myocardial infarction (MI). The biological basis for these beneficial effects remains incompletely understood. We sought to explore the mechanisms of IL-1β-targeted therapies. In mice with early atherosclerosis (ApoE^–/– mice on a high-cholesterol diet for 6 weeks), we found that 3 weeks of NACHT, LRR, and PYD domains-containing protein 3 (NLRP3)-inflammasome inhibition or anti-IL-1β treatment (using either MCC950, an NLRP3-inflammasome inhibitor which blocks production and release of active IL-1β, or a murine analogue of canakinumab) dampened accumulation of leucocytes in atherosclerotic aortas, which consequently resulted in slower progression of atherosclerosis. Causally, we found that endothelial cells from atherosclerotic aortas lowered expression of leucocyte chemoattractants and adhesion molecules upon NLRP3-inflammasome inhibition, indicating that NLRP3-inflammasome- and IL-1β-targeted therapies reduced blood leucocyte recruitment to atherosclerotic aortas. In accord, adoptive transfer experiments revealed that anti-IL-1β treatment mitigated blood myeloid cell uptake to atherosclerotic aortas. We further report that anti-IL-1β treatment and NLRP3-inflammasome inhibition reduced inflammatory leucocyte supply by decreasing proliferation of bone marrow haematopoietic stem and progenitor cells, demonstrating that suppression of IL-1β and the NLRP3-inflammasome lowered production of disease-propagating leucocytes. Using bone marrow reconstitution experiments, we observed that haematopoietic cell-specific NLRP3-inflammasome activity contributed to both enhanced recruitment and increased supply of blood inflammatory leucocytes. Further experiments that queried whether anti-IL-1β treatment reduced vascular inflammation also in post-MI accelerated atherosclerosis documented the operation of convergent mechanisms (reduced supply and uptake of inflammatory leucocytes). In line with our pre-clinical findings, post-MI patients on canakinumab treatment showed reduced blood monocyte numbers. Our murine and human data reveal that anti-IL-1β treatment and NLRP3-inflammasome inhibition dampened vascular inflammation and progression of atherosclerosis through reduced blood inflammatory leucocyte (i) supply and (ii) uptake into atherosclerotic aortas providing additional mechanistic insights into links between haematopoiesis and atherogenesis, and into the beneficial effects of NLRP3-inflammasome- and IL-1β-targeted therapies. Our data suggest that both anti-IL-1β treatment and NLRP3-inflammasome inhibition beneficially alter the course of atherosclerosis by (i) dampening inflammatory leucocyte production in the bone marrow and consequently suppressing supply of these cells and (ii) de-activating plaque endothelial cells and hence reducing inflammatory leucocyte recruitment from blood to plaque.

In the last few decades, many pathogenic or likely pathogenic genetic mutations in over hundred different genes have been described for non-ischemic, genetic cardiomyopathies. However, the functional knowledge about most of these mutations is still limited because the generation of adequate animal models is time-consuming and challenging. Therefore, human induced pluripotent stem cells (iPSCs) carrying specific cardiomyopathy-associated mutations are a promising alternative. Since the original discovery that pluripotency can be artificially induced by the expression of different transcription factors, various patient-specific-induced pluripotent stem cell lines have been generated to model non-ischemic, genetic cardiomyopathies in vitro. In this review, we describe the genetic landscape of non-ischemic, genetic cardiomyopathies and give an overview about different human iPSC lines, which have been developed for the disease modeling of inherited cardiomyopathies. We summarize different methods and protocols for the general differentiation of human iPSCs into cardiomyocytes. In addition, we describe methods and technologies to investigate functionally human iPSC-derived cardiomyocytes. Furthermore, we summarize novel genome editing approaches for the genetic manipulation of human iPSCs. This review provides an overview about the genetic landscape of inherited cardiomyopathies with a focus on iPSC technology, which might be of interest for clinicians and basic scientists interested in genetic cardiomyopathies.

Aims: Current troponin cut-offs suggested for the post-operative workup of patients following coronary artery bypass graft (CABG) surgery are based on studies using non-high-sensitive troponin assays or are arbitrarily chosen. We aimed to identify an optimal cut-off and timing for a proprietary high-sensitivity cardiac troponin I (hs-cTnI) assay to facilitate post-operative clinical decision-making. Methods and results: We performed a retrospective analysis of all patients undergoing elective isolated CABG at our centre between January 2013 and May 2019. Of 4684 consecutive patients, 161 patients (3.48%) underwent invasive coronary angiography after surgery, of whom 86 patients (53.4%) underwent repeat revascularization. We found an optimal cut-off value for peak hs-cTnI of >13 000 ng/L [>500× the upper reference limit (URL)] to be significantly associated with repeat revascularization within 48 h after surgery, which was internally validated through random repeated sampling with 1000 iterations. The same cut-off also predicted 30-day major adverse cardiovascular events and all-cause mortality after a median follow-up of 3.1 years, which was validated in an external cohort. A decision tree analysis of serial hs-cTnI measurements showed no added benefit of hs-cTnI measurements in patients with electrocardiographic or echocardiographic abnormalities or haemodynamic instability. Likewise, early post-operative hs-cTnI elevations had a low yield for clinical decision-making and only later elevations (at 12–16 h post-operatively) using a threshold of 8000 ng/L (307× URL) were significantly associated with repeat revascularization with an area under the curve of 0.92 (95% confidence interval 0.88–0.95). Conclusion: Our data suggest that for hs-cTnI, higher cut-offs than currently recommended should be used in the post-operative management of patients following CABG.

Currently, little is known about the genetic background of restrictive cardiomyopathy (RCM). Herein, we screened an index patient with RCM in combination with atrial fibrillation using a next generation sequencing (NGS) approach and identified the heterozygous mutation DES-c.735G>C. As DES-c.735G>C affects the last base pair of exon-3, it is unknown whether putative missense or splice site mutations are caused. Therefore, we applied nanopore amplicon sequencing revealing the expression of a transcript without exon-3 in the explanted myocardial tissue of the index patient. Western blot analysis verified this finding at the protein level. In addition, we performed cell culture experiments revealing an abnormal cytoplasmic aggregation of the truncated desmin form (p.D214-E245del) but not of the missense variant (p.E245D). In conclusion, we show that DES-c.735G>C causes a splicing defect leading to exon-3 skipping of the DES gene. DES-c.735G>C can be classified as a pathogenic mutation associated with RCM and atrial fibrillation. In the future, this finding might have relevance for the genetic understanding of similar cases.

Objectives: Minimally-invasive direct coronary artery bypass (MIDCAB) is a less-invasive alternative to full sternotomy off-pump coronary artery bypass (FS-OPCAB) revascularization of the left anterior descending artery (LAD). Some studies suggested that MIDCAB is associated with a greater risk of graft occlusion and repeat revascularization than FS-OPCAB LIMA-to-LAD grafting. Data comparing MIDCAB to FS-OPCAB with regard to long-term follow-up is scarce. We compared short- and long-term results of MIDCAB vs. FS-OPCAB revascularization over a maximum follow-up period of 10 years.Patients and methods: From December 2009 to June 2020, 388 elective patients were included in our retrospective study. 229 underwent MIDCAB, and 159 underwent FS-OPCAB LIMA-to-LAD grafting. Inverse probability of treatment weighting (IPTW) was used to adjust for selection bias and to estimate treatment effects on short- and long-term outcomes. IPTW-adjusted Kaplan–Meier estimates by study group were calculated for all-cause mortality, stroke, the risk of repeat revascularization and myocardial infarction up to a maximum follow-up of 10 years.Results: MIDCAB patients had less rethoracotomies (n = 13/3.6% vs. n = 30/8.0%, p = 0.012), fewer transfusions (0.93 units ± 1.83 vs. 1.61 units ± 2.52, p < 0.001), shorter mechanical ventilation time (7.6 ± 4.7 h vs. 12.1 ± 26.4 h, p = 0.005), and needed less hemofiltration (n = 0/0% vs. n = 8/2.4%, p = 0.004). Thirty-day mortality did not differ significantly between the two groups (n = 0/0% vs. n = 3/0.8%, p = 0.25). Long-term outcomes did not differ significantly between study groups. In the FS-OPCAB group, the probability of survival at 1, 5, and 10 years was 98.4%, 87.8%, and 71.7%, respectively. In the MIDCAB group, the corresponding values were 98.4%, 87.7%, and 68.7%, respectively (RR1.24, CI0.87–1.86, p = 0.7). In the FS group, the freedom from stroke at 1, 5, and 10 years was 97.0%, 93.0%, and 93.0%, respectively. In the MIDCAB group, the corresponding values were 98.5%, 96.9%, and 94.3%, respectively (RR0.52, CI0.25–1.09, p = 0.06). Freedom from repeat revascularization at 1, 5, and 10 years in the FS-OPCAB group was 92.2%, 84.7%, and 79.5%, respectively. In the MIDCAB group, the corresponding values were 94.8%, 90.2%, and 81.7%, respectively (RR0.73, CI0.47–1.16, p = 0.22).Conclusion: MIDCAB is a safe and efficacious technique and offers comparable long-term results regarding mortality, stroke, repeat revascularization, and freedom from myocardial infarction when compared to FS-OPCAB.