Several peripheral blood mononuclear cell (PBMC)–derived cell populations can promote angiogenesis, and differences in CD34+ or CD14+ surface expression have been used to separate PBMC subpopulations ...in this respect. AngiomiRs, microRNAs regulating angiogenesis, are key regulators of angiogenic processes. The present study examines differential angiomiR expression/secretion from CD34+/CD14+, CD34+/CD14−, CD34−/CD14+, and CD34−/CD14− PBMC subsets and their relevance for different proangiogenic properties. Notably, both circulating human CD34+/14+ and CD34+/14− PBMC subsets and their supernatants exerted more potent proangiogenic effects compared with CD34− PBMC subsets. MiR-126 was identified as most differentially expressed angiomiR in CD34+ compared with CD34− PBMC subsets, determined by miR-array and RT-PCR validation. Modulation of miR-126 by anti–miR-126 or miR-mimic-126 treatment resulted in significant loss or increase of proangiogenic effects of CD34+ PBMCs. MiR-126 levels in supernatants of CD34+ PBMC subsets were substantially higher compared with CD34− PBMC subsets. MiR-126 was secreted in microvesicles/exosomes, and inhibition of their release impaired CD34+ PBMCs proangiogenic effects. Notably, high-glucose treatment or diabetes reduced miR-126 levels of CD34+ PBMCs, associated with impaired proangiogenic properties that could be rescued by miR-mimic-126 treatment. The present findings provide a novel molecular mechanism underlying increased proangiogenic effects of CD34+ PBMCs, that is, angiomiR-126 expression/secretion. Moreover, an alteration of angiomiR-126 expression in CD34+ PBMCs in diabetes provides a novel pathway causing impaired proangiogenic effects.
•AngiomiR-126 is secreted from circulating CD34+ cells and acts as a signaling mechanism of pro-angiogenic effects on endothelial cells, which is impaired in diabetes.
Yohimbine is a highly selective and potent α
2
-adrenoceptor antagonist, which is usually treated as an adjunction for impotence, as well for weight loss and natural bodybuilding aids. However, it ...was recently reported that Yohimbine causes myocardial injury and controversial results were reported in the setting of cardiac diseases. Here, we used human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) as a model system to explore electrophysiologic characterization after exposure to Yohimbine. HiPSC-CMs were differentiated by employment of inhibitory Wnt compounds. For analysis of electrophysiological properties, conventional whole-cell patch-clamp recording was used. Specifically, spontaneous action potentials, pacemaker currents (
I
f
), sodium (Na
+
) channel (
I
Na
), and calcium (Ca
++
) channel currents (
I
Ca
) were assessed in hiPSC-CMs after exposure to Yohimbine. HiPSC-CMs expressed sarcomeric-α-actinin and MLC2V proteins, as well as exhibited ventricular-like spontaneous action potential waveform. Yohimbine inhibited frequency of hiPSC-CMs spontaneous action potentials and significantly prolonged action potential duration in a dose-dependent manner. In addition, rest potential, threshold potential, amplitude, and maximal diastolic potential were decreased, whereas APD
50
/APD
90
was prolonged. Yohimbine inhibited the amplitude of
I
Na
in low doses (IC
50
= 14.2 μM,
n
= 5) and inhibited
I
Ca
in high doses (IC
50
= 139.7 μM,
n
= 5). Whereas Yohimbine did not affect the activation curves, treatment resulted in left shifts in inactivation curves of both Na
+
and Ca
++
channels. Here, we show that Yohimbine induces direct cardiotoxic effects on spontaneous action potentials of
I
Na
and
I
Ca
in hiPSC-CMs. Importantly, these effects were not mediated by α
2
-adrenoceptor signaling. Our results strongly suggest that Yohimbine directly and negatively affects electrophysiological properties of human cardiomyocytes. These findings are highly relevant for potential application of Yohimbine in patients with atrioventricular conduction disorder.
Inflammasomes are crucial gatekeepers of the immune response, but their maladaptive activation associates with inflammatory pathologies. Besides canonical activation, monocytes can trigger ...non-transcriptional or rapid inflammasome activation that has not been well defined in the context of acute myocardial infarction (AMI). Rapid transcription-independent inflammasome activation induced by simultaneous TLR priming and triggering stimulus was measured by caspase-1 (CASP1) activity and interleukin release. Both classical and intermediate monocytes from healthy donors exhibited robust CASP1 activation, but only classical monocytes produced high mature interleukin-18 (IL18) release. We also recruited a limited number of coronary artery disease (CAD, n=31) and AMI (n=29) patients to evaluate their inflammasome function and expression profiles. Surprisingly, monocyte subpopulations isolated from blood collected during percutaneous coronary intervention (PCI) from AMI patients presented diminished CASP1 activity and abrogated IL18 release despite increased NLRP3 gene expression. This unexpected attenuated rapid inflammasome activation was accompanied by a significant increase of TNFAIP3 and IRAKM expression. Moreover, TNFAIP3 protein levels of circulating monocytes showed positive correlation with high sensitive troponin T (hsTnT), implying an association between TNFAIP3 upregulation and the severity of tissue injury. We suggest this monocyte attenuation to be a protective phenotype aftermath following a very early inflammatory wave in the ischemic area. Damage-associated molecular patterns (DAMPs) or other signals trigger a transitory negative feedback loop within newly recruited circulating monocytes as a mechanism to reduce post-injury tissue damage.
Background This study sought to investigate the role of postprocedural troponin elevations in mortality prediction after transcatheter aortic valve implantation and to define the threshold at which ...clinically relevant postprocedure myocardial injury determines mortality. Methods and Results A total of 1333 consecutive patients with transcatheter aortic valve implantation with available postprocedural high-sensitivity cardiac troponin T measurements were included in the analysis. The threshold at which postprocedure myocardial injury determines long-term mortality was identified using restricted cubic spline analysis. A >18.3-fold increase of troponin above the upper reference limit was identified as threshold for relevant postprocedure myocardial injury. Associations remained significant in a landmark analysis between 30 days and 2 years (hazard ratio HR, 1.61, 95% CI, 1.13-2.28;
=0.01), after adjusting for known confounders (adjusted HR, 1.90 95% CI, 1.40-2.57;
<0001), and in subgroups of patients with coronary artery disease (adjusted HR, 2.17 95% CI, 1.44-3.29;
<0.001), renal dysfunction (adjusted HR, 1.88 95% CI, 1.35-2.62;
<0.001), and intermediate/high surgical risk (adjusted HR, 2.70 95% CI, 1.40-5.22;
=0.003). Conclusions This study determined a troponin threshold for the identification of patients at increased mortality risk after transcatheter aortic valve implantation. The proposed definition of postprocedure myocardial injury advances risk stratification in patients with transcatheter aortic valve implantation and may assist in postprocedural patient management.
Perioperative myocardial ischemia is common in high-risk patients. The use of interventional revascularisation or even thrombolysis is limited in this patient subset due to exceedingly high bleeding ...risks. Blockade of voltage-gated sodium channels (VGSC) with lidocaine had been suggested to reduce infarct size and cardiomyocyte cell death in ischemia/reperfusion models. However, the impact of lidocaine on cardiac function during sustained ischemia still remains unclear.
Sustained myocardial ischemia was induced by ligation of the left anterior descending artery in 12-16 weeks old male BALB/c mice. Subcutaneous lidocaine (30 mg/kg) was used to block VGSC. Cardiac function was quantified at baseline and at 72h by conventional and speckle-tracking based echocardiography to allow high-sensitivity in vivo phenotyping. Infarct size and cardiomyocyte cell death were assessed post mortem histologically and indirectly using troponin measurements.
Ischemia strongly impaired both, global systolic and diastolic function, which were partially rescued in lidocaine treated in mice. No differences regarding infarct size and cardiomyocyte cell death were observed. Mechanistically, and as shown with speckle-tracking analysis, lidocaine specifically improves residual contractility in the ischemic but not in the remote, non-ischemic myocardium.
VGSC blockade with lidocaine rescues function of ischemic myocardium as a potential bridging to revascularisation in the setting of perioperative myocardial ischemia.
Ischemic cardiomyopathy, driven by loss of cardiomyocytes and inadequate proliferative response, persists to be a major global health problem. Using a functional high-throughput screening, we ...assessed differential proliferative potential of 2019 miRNAs after transient hypoxia by transfecting both miR-inhibitor and miR-mimic libraries in human iPSC-CM. Whereas miR-inhibitors failed to enhance EdU uptake, overexpression of 28 miRNAs substantially induced proliferative activity in hiPSC-CM, with an overrepresentation of miRNAs belonging to the primate-specific C19MC-cluster. Two of these miRNAs, miR-515-3p and miR-519e-3p, increased markers of early and late mitosis, indicative of cell division, and substantially alter signaling pathways relevant for cardiomyocyte proliferation in hiPSC-CM.
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•We performed the largest high-throughput screening in human iPSC-CM using 2019 miRNAs•Inhibition of individual miRNAs failed to induce proliferative activity in hiPSC-CM•In contrast, 28 miRNA-mimics substantially enhanced cell cycling in hiPSC-CM•Specifically, miR-515 and miR-519 from the C19MC induce cell division in hiPSC-CM
Cardiovascular medicine; Genetics; Molecular biology
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