Impact of Access Site on Periprocedural Bleeding and Cerebral and Coronary Events in High-Bleeding-Risk Percutaneous Coronary Intervention: Findings from the RIVA-PCI Trial.

INTRODUCTION: The preference for using transradial access (TRA) over transfemoral access (TFA) in patients requiring percutaneous coronary intervention (PCI) is based on evidence suggesting that TRA is associated with less bleeding and fewer vascular complications, shorter hospital stays, improved quality of life, and a potential beneficial effect on mortality. We have limited study data comparing the two access routes in a patient population with atrial fibrillation (AF) undergoing PCI, who have a particular increased risk of bleeding, while AF itself is associated with an increased risk of thromboembolism. METHODS: Using data from the RIVA-PCI registry, which includes patients with AF undergoing PCI, we analyzed a high-bleeding-risk (HBR) cohort. These patients were predominantly on oral anticoagulants (OAC) for AF, and the PCI was performed via radial or femoral access. Endpoints examined were in-hospital bleeding (BARC 2-5), cerebral events (TIA, hemorrhagic or ischemic stroke) and coronary events (stent thrombosis and myocardial infarction). RESULTS: Out of 1636 patients, 854 (52.2%) underwent TFA, while 782 (47.8%) underwent the procedure via TRA, including nine patients with brachial artery puncture. The mean age was 75.5 years. Groups were similar in terms of age, sex distribution, AF type, cardiovascular history, risk factors, and comorbidities, except for a higher incidence of previous bypass surgeries, heart failure, hyperlipidemia, and chronic kidney disease (CKD) with a glomerular filtration rate (GFR) < 60 ml/min in the TFA group. No clinically relevant differences in antithrombotic therapy and combinations were present at the time of PCI. However, upon discharge, transradial PCI patients had a higher rate of triple therapy, while dual therapy was preferred after transfemoral procedures. Radial access was more frequently chosen for non-ST-segment elevation myocardial infarction (NSTEMI) and unstable angina pectoris (UAP) cases (NSTEMI 26.6% vs. 17.0%, p < 0.0001; UAP 21.5% vs. 14.5%, p < 0.001), while femoral access was more common for elective PCI (60.3% vs. 44.1%, p < 0.0001). No differences were observed for ST-segment elevation myocardial infarction (STEMI). Both groups had similar rates of cerebral events (TFA 0.2% vs. TRA 0.3%, p = 0.93), but the TFA group had a higher incidence of bleeding (BARC 2-5) (4.2% vs. 1.5%, p < 0.01), mainly driven by BARC 3 bleeding (1.5% vs. 0.4%, p < 0.05). No significant differences were found for stent thrombosis and myocardial infarction (TFA 0.2% vs. TRA 0.3%, p = 0.93; TFA 0.4% vs. TRA 0.1%, p = 0.36). CONCLUSIONS: In HBR patients with AF undergoing PCI for acute or chronic coronary syndrome, the use of TRA might be associated with a decrease in in-hospital bleeding, while not increasing the risk of embolic or ischemic events compared to femoral access. Further studies are required to confirm these preliminary findings.

Rivaroxaban in Patients With Atrial Fibrillation Who Underwent Percutaneous Coronary Intervention in Clinical Practice.

Little is known about the efficacy and safety of rivaroxaban in patients with atrial fibrillation (AF) who underwent percutaneous coronary intervention (PCI) in clinical practice. We therefore conducted a prospective observational study to determine the rate of ischemic, embolic, and bleeding events in patients with AF and PCI treated with rivaroxaban in a real-world experience. The RIVA-PCI ("rivaroxaban in patients with AF who underwent PCI") (clinicaltrials.gov NCT03315650) is a prospective, noninterventional, multicenter study with a follow-up until 14 months, including patients with AF who underwent PCI discharged with rivaroxaban. Between January 2018 and March 2020, 700 patients with PCI treated with rivaroxaban (elective in 50.1%, non-ST-elevation acute coronary syndrome 43.0%, ST-elevation myocardial infarction in 6.9%) were enrolled at 51 German hospitals. After PCI, a dual antithrombotic therapy consisting of rivaroxaban and a P2Y12 inhibitor was administered in 70.7% and triple antithrombotic therapy in 27.9%, respectively. Follow-up information could be obtained in 695 patients (99.3%). Rivaroxaban has been stopped prematurely in 21.6% of patients. Clinical events under rivaroxaban during the 14-month follow-up compared with those observed in the PIONEER-AF PCI trial included cardiovascular death (2.0% % vs 2.0%), myocardial infarction (0.9% vs 3.0%), stent thrombosis (0.2% vs 0.8%), stroke (1.3% vs 1.3%), International Society on Thrombosis and Haemostasis major (4.2% vs 3.9%), and International Society on Thrombosis and Haemostasis nonmajor clinically relevant bleeding (15.3% vs 12.9%). Therefore, in this real-world experience, rivaroxaban in patients with AF who underwent PCI is associated with ischemic and bleeding event rates comparable with those observed in the randomized PIONEER-AF PCI trial.

Current status of antithrombotic therapy and in-hospital outcomes in patients with atrial fibrillation undergoing percutaneous coronary intervention in Germany.

BACKGROUND: Little is known about current patterns of antithrombotic therapy in patients with atrial fibrillation (AF) undergoing percutaneous coronary intervention (PCI) in clinical practice in Germany. METHODS: The RIVA-PCI is a prospective, non-interventional, multicenter study with follow-up until hospital discharge including consecutive patients with AF undergoing PCI. RESULTS: Between January 2018 and March 2020, 1636 patients (elective in 52.6%, non-ST elevation acute coronary syndrome [NSTE-ACS] in 39.3%, ST-elevation myocardial infarction in 8.2%) from 51 German hospitals were enrolled in the study. After PCI a dual antithrombotic therapy (DAT) consisting of OAC and a P2Y12 inhibitor was given to 66.0%, triple antithrombotic therapy (TAT) to 26.0%, dual antiplatelet therapy to 5.5%, and a mono-therapy to 2.5% of the patients. Non-vitamin K antagonist oral anticoagulants (NOACs) were given to 82.4% and vitamin K antagonists to 11.5% of the patients. In-hospital events included death in 12 cases (0.7%), myocardial infarction, stent thrombosis, and ischemic stroke in four (0.2%) patients each, while 2.8% of patients had bleeding complications. The recommended durations for DAT or TAT at discharge were 1 month (1.5%), 3 months (2.1%), 6 months (43.1%), and 12 months (45.6%), with a 6-month course of DAT (47.7%) most often recommended after elective PCI and a 12-month course of DAT (40.1%) after ACS. CONCLUSION: The preferred therapy after PCI in patients with AF is DAT with a NOAC and clopidogrel. In-hospital ischemic and bleeding events were rare. The recommended durations for combination therapy vary considerably.

Quality of life of patients with coronary heart disease treated with the bioresorbable vascular scaffold (ABSORB™): 2-year results from the GABI-R-registry.

BACKGROUND: Numerous studies have reported clinical endpoints following coronary revascularization using bioresorbable vascular scaffolds (BVS), while information about the impact on health-related quality of life is sparse. In this analysis of the German-Austrian ABSORB RegIstRy, the 2 year results concerning quality of life development in a large cohort of patients treated with BVS were reported. METHODS: Data were collected at baseline as well as 30 days, 6 and 24 months after coronary revascularization using BVS. The EQ-5D score, EQ visual analogue scale (VAS) and Seattle Angina Questionnaire (SAQ) were determined for each time point. Patients were categorized according to the indication for coronary revascularization [acute coronary syndrome (ACS), stable angina pectoris (SAP), silent myocardial ischemia (SMI), or other]. Binary logistic regression analysis was performed to determine factors that predict above-average scores two years after implantation. RESULTS: Data from 1317 patients in 88 centres were included. Reasons for revascularization were: ACS (n = 643), SAP (n = 443), SMI (n = 52), and other (n = 179). Mean EQ-5D was significantly increased after six months, while a value comparable to baseline was found two years after implantation. EQ VAS and four of five dimensions of SAQ were significantly improved over baseline at all follow-up surveys. Particularly strong improvements were seen in SAQ scores angina frequency and quality of life. Binary regressions showed different statistically significant predictors in the respective models. CONCLUSIONS: Following coronary revascularization with BVS strong decrease in self-reported angina frequency and increase of self-reported quality of life were observed with continuous improvements over two years of follow-up. Trial registration ClinicalTrials.gov Identifier: NCT02066623.

Live-cell assays to identify regulators of ER-to-Golgi trafficking.

We applied fluorescence microscopy-based quantitative assays to living cells to identify regulators of endoplasmic reticulum (ER)-to-Golgi trafficking and/or Golgi complex maintenance. We first validated an automated procedure to identify factors which influence Golgi-to-ER relocalization of GalT-CFP (ß1,4-galactosyltransferase I-cyan fluorescent protein) after brefeldin A (BFA) addition and/or wash-out. We then tested 14 proteins that localize to the ER and/or Golgi complex when overexpressed for a role in ER-to-Golgi trafficking. Nine of them interfered with the rate of BFA-induced redistribution of GalT-CFP from the Golgi complex to the ER, six of them interfered with GalT-CFP redistribution from the ER to a juxtanuclear region (i.e. the Golgi complex) after BFA wash-out and six of them were positive effectors in both assays. Notably, our live-cell approach captures regulator function in ER-to-Golgi trafficking, which was missed in previous fixed cell assays, as well as assigns putative roles for other less characterized proteins. Moreover, we show that our assays can be extended to RNAi and chemical screens.

miR-17-5p regulates endocytic trafficking through targeting TBC1D2/Armus.

miRNA cluster miR-17-92 is known as oncomir-1 due to its potent oncogenic function. miR-17-92 is a polycistronic cluster that encodes 6 miRNAs, and can both facilitate and inhibit cell proliferation. Known targets of miRNAs encoded by this cluster are largely regulators of cell cycle progression and apoptosis. Here, we show that miRNAs encoded by this cluster and sharing the seed sequence of miR-17 exert their influence on one of the most essential cellular processes - endocytic trafficking. By mRNA expression analysis we identified that regulation of endocytic trafficking by miR-17 can potentially be achieved by targeting of a number of trafficking regulators. We have thoroughly validated TBC1D2/Armus, a GAP of Rab7 GTPase, as a novel target of miR-17. Our study reveals regulation of endocytic trafficking as a novel function of miR-17, which might act cooperatively with other functions of miR-17 and related miRNAs in health and disease.

A Potential of microRNAs for High-Content Screening.

In the last years miRNAs have increasingly been recognised as potent posttranscriptional regulators of gene expression. Possibly, miRNAs exert their action on virtually any biological process by simultaneous regulation of numerous genes. The importance of miRNA-based regulation in health and disease has inspired research to investigate diverse aspects of miRNA origin, biogenesis, and function. Despite the recent rapid accumulation of experimental data, and the emergence of functional models, the complexity of miRNA-based regulation is still far from being well understood. In particular, we lack comprehensive knowledge as to which cellular processes are regulated by which miRNAs, and, furthermore, how temporal and spatial interactions of miRNAs to their targets occur. Results from large-scale functional analyses have immense potential to address these questions. In this review, we discuss the latest progress in application of high-content and high-throughput functional analysis for the systematic elucidation of the biological roles of miRNAs.

Cell arrays for the measurement of organelle dynamics in living cells.

The Golgi complex is the central organelle in the secretory membrane trafficking and its organization strongly depends upon the flow of coming and leaving material. The principles of cargo transfer to, through, and away from the Golgi complex were investigated in numerous studies. However, the knowledge of how the Golgi complex responses to changes in diverse trafficking events (e.g., ER exit block) on a molecular level is far from being complete. In order to identify regulatory molecules playing a role in the dynamic organization of the Golgi complex, we established a fluorescent microscopy-based quantitative assay to measure rates of the Golgi redistribution and assembly after addition and washout of BFA, respectively. At first, we tested our system under the condition of over-expression of GFP-tagged proteins. We measured their influence upon BFA-induced effects in a format, suitable for large-scale studies in living cell, namely cell arrays. The approach can be applied for large-scale RNA interference studies as well as for chemical screening.

Activation-induced internalization differs for the tetraspanins CD9 and Tspan8: Impact on tumor cell motility.

Exosomes are most important intercellular communicators and tetraspanins/tetraspanin-complexes have been suggested to play an important role in exosomal target cell selection. We have shown that only exosomes expressing a Tspan8-CD49d complex preferentially bind endothelial cells, which initiates angiogenesis. This finding was unexpected as in the exosome donor cell Tspan8 is associated with CD49c and the tetraspanins CD9 and CD151. In view of the discussed therapeutic power of exosomes as message/drug transporter, it became important to clarify the mechanisms accounting for the distinct Tspan8-web in the cell membrane versus exosomes. We therefore compared the route of Tspan8 and Tspan8-chimera internalization, where the N- and/or C-terminal regions were exchanged with the corresponding regions of CD9 or CD151. Activation-induced Tspan8-internalization proceeds more rapidly than CD9 internalization and is accompanied by disassembly of the Tspan8-CD9-CD151 membrane complex in resting cells. Tspan8-internalization relies on the association of the Tspan8 N-terminal region with intersectin-2, a multimodular complex involved in clathrin-coated pit internalization. Internalization and recovery of Tspan8 in early endosomes is further promoted by the recruitment of CD49d such that only in PMA-activated cells a Tspan8-INS2-CD49d-clathrin complex is recovered in cholesterol-depletion-resistant membrane microdomains. PMA-induced Tspan8-internalization promotes cell migration, but reduces matrix and cell adhesion. Thus, stimulation initiates tetraspanin-web rearrangements, which have strong functional consequences for the cell, exosome-delivery and exosome target selection. This knowledge will be essential for generating tailored therapeutic exosomes.

The tetraspanin D6.1A and its molecular partners on rat carcinoma cells.

Tetraspanins function as molecular organizers of multi-protein complexes by assembling primary complexes of a relatively low mass into extensive networks involved in cellular signalling. In this paper, we summarize our studies performed on the tetraspanin D6.1A/CO-029/TM4SF3 expressed by rat carcinoma cells. Primary complexes of D6.1A are almost indistinguishable from complexes isolated with anti-CD9 antibody. Indeed, both tetraspanins directly associate with each other and with a third tetraspanin, CD81. Moreover, FPRP (prostaglandin F2alpha receptor-regulatory protein)/EWI-F/CD9P-1), an Ig superfamily member that has been described to interact with CD9 and CD81, is also a prominent element in D6.1A complexes. Primary complexes isolated with D6.1A-specific antibody are clearly different from complexes containing the tetraspanin CD151. CD151 is found to interact only with D6.1A if milder conditions, i.e. lysis with LubrolWX instead of Brij96, are applied to disrupt cellular membranes. CD151 probably mediates the interaction of D6.1A primary complexes with alpha3beta1 integrin. In addition, two other molecules were identified to be part of D6.1A complexes at this higher level of association: type II phosphatidylinositol 4-kinase and EpCAM, an epithelial marker protein overexpressed by many carcinomas. The characterization of the D6.1A core complex and additional more indirect interactions will help to elucidate the role in tumour progression and metastasis attributed to D6.1A.

Palmitoylation supports assembly and function of integrin-tetraspanin complexes.

As observed previously, tetraspanin palmitoylation promotes tetraspanin microdomain assembly. Here, we show that palmitoylated integrins (alpha3, alpha6, and beta4 subunits) and tetraspanins (CD9, CD81, and CD63) coexist in substantially overlapping complexes. Removal of beta4 palmitoylation sites markedly impaired cell spreading and signaling through p130Cas on laminin substrate. Also in palmitoylation-deficient beta4, secondary associations with tetraspanins (CD9, CD81, and CD63) were diminished and cell surface CD9 clustering was decreased, whereas core alpha6beta4-CD151 complex formation was unaltered. There is also a functional connection between CD9 and beta4 integrins, as evidenced by anti-CD9 antibody effects on beta4-dependent cell spreading. Notably, beta4 palmitoylation neither increased localization into "light membrane" fractions of sucrose gradients nor decreased solubility in nonionic detergents-hence it does not promote lipid raft association. Instead, palmitoylation of beta4 (and of the closely associated tetraspanin CD151) promotes CD151-alpha6beta4 incorporation into a network of secondary tetraspanin interactions (with CD9, CD81, CD63, etc.), which provides a novel framework for functional regulation.

Palmitoylation of tetraspanin proteins: modulation of CD151 lateral interactions, subcellular distribution, and integrin-dependent cell morphology.

Here we demonstrate that multiple tetraspanin (transmembrane 4 superfamily) proteins are palmitoylated, in either the Golgi or a post-Golgi compartment. Using CD151 as a model tetraspanin, we identified and mutated intracellular N-terminal and C-terminal cysteine palmitoylation sites. Simultaneous mutations of C11, C15, C242, and C243 (each to serine) eliminated >90% of CD151 palmitoylation. Notably, palmitoylation had minimal influence on the density of tetraspanin protein complexes, did not promote tetraspanin localization into detergent-resistant microdomains, and was not required for CD151-alpha 3 beta 1 integrin association. However, the CD151 tetra mutant showed markedly diminished associations with other cell surface proteins, including other transmembrane 4 superfamily proteins (CD9, CD63). Thus, palmitoylation may be critical for assembly of the large network of cell surface tetraspanin-protein interactions, sometimes called the "tetraspanin web." Also, compared with wild-type CD151, the tetra mutant was much more diffusely distributed and showed markedly diminished stability during biosynthesis. Finally, expression of the tetra-CD151 mutant profoundly altered alpha 3 integrin-deficient kidney epithelial cells, such that they converted from a dispersed, elongated morphology to an epithelium-like cobblestone clustering. These results point to novel biochemical and biological functions for tetraspanin palmitoylation.