Magnitude of Type I Interferon Responses by Plasmacytoid Dendritic Cells After TLR7 Stimulation Is Associated With Human Immunodeficiency Virus Type 1 (HIV-1) Reservoir Sizes in Cisgender Women With HIV-1 on Antiretroviral Therapy.

Human immunodeficiency virus type 1 (HIV-1) disease manifestations differ between cisgender women and men, including better control of viral replication during primary infection and less frequent residual HIV-1 replication on antiretroviral therapy (ART) in cisgender women with HIV-1 (WWH). Investigating plasmacytoid dendritic cell (pDC) functions and HIV-1 reservoir sizes in 20 WWH on stable ART, we observed inverse correlations between interferon-α and tumor necrosis factor responses of pDCs to Toll-like receptor 7/8 stimulation and intact/total proviral HIV-1 DNA levels. Additionally, ISG15 mRNA levels in peripheral blood mononuclear cells correlated with cytokine responses of pDCs. These findings demonstrate an association between higher type I interferon responses and lower HIV-1 reservoir sizes in WWH on ART, warranting studies to identify the underlying mechanisms.

Natural killer cell-mediated ADCC in SARS-CoV-2-infected individuals and vaccine recipients.

COVID-19, caused by SARS-CoV-2, has emerged as a global pandemic. While immune responses of the adaptive immune system have been in the focus of research, the role of NK cells in COVID-19 remains less well understood. Here, we characterized NK cell-mediated SARS-CoV-2 antibody-dependent cellular cytotoxicity (ADCC) against SARS-CoV-2 spike-1 (S1) and nucleocapsid (NC) protein. Serum samples from SARS-CoV-2 resolvers induced significant CD107a-expression by NK cells in response to S1 and NC, while serum samples from SARS-CoV-2-negative individuals did not. Furthermore, serum samples from individuals that received the BNT162b2 vaccine induced strong CD107a expression by NK cells that increased with the second vaccination and was significantly higher than observed in infected individuals. As expected, vaccine-induced responses were only directed against S1 and not against NC protein. S1-specific CD107a responses by NK cells were significantly correlated to NK cell-mediated killing of S1-expressing cells. Interestingly, screening of serum samples collected prior to the COVID-19 pandemic identified two individuals with cross-reactive antibodies against SARS-CoV-2 S1, which also induced degranulation of NK cells. Taken together, these data demonstrate that antibodies induced by SARS-CoV-2 infection and anti-SARS-CoV-2 vaccines can trigger significant NK cell-mediated ADCC activity, and identify some cross-reactive ADCC-activity against SARS-CoV-2 by endemic coronavirus-specific antibodies.

Human pDCs display sex-specific differences in type I interferon subtypes and interferon α/ß receptor expression.

The outcomes of many diseases differ between women and men, with women experiencing a higher incidence and more severe pathogenesis of autoimmune and some infectious diseases. It has been suggested that this is partially due to activation of plasmacytoid dendritic cells (pDCs), the main producers of interferon (IFN)-α, in response to toll-like receptor (TLR)7 stimulation. We investigated the induction of type I IFN (IFN-I) subtypes upon TLR7 stimulation on isolated pDCs. Our data revealed a sex-specific differential expression of IFN-Is, with pDCs from females showing a significantly higher mRNA expression of all 13 IFN-α subtypes. In addition, pDCs from females had higher levels of IFN-ß mRNA after stimulation, indicating that sex differences in IFN-I production by pDCs were mediated by a signaling event upstream of the first loop of IFN-I mRNA transcription. Furthermore, the surface expression levels of the common IFN-α/ß receptor subunit 2 were significantly higher on pDCs from females in comparison to males. These data indicate that higher IFN-α production is already established at the mRNA level and propose a contribution of higher IFN-α/ß receptor 2 expression on pDCs to the immunological differences in IFN-I production observed between females and males.

TLR7-mediated activation of XBP1 correlates with the IFNα production in humans.

The transcription factor X-box binding protein 1 (XBP1) represents a key component of the endoplasmatic reticulum (ER) stress response and is required for the production of several pro-inflammatory cytokines. XBP1 is furthermore essential for the development and survival of plasmacytoid dendritic cells (pDCs), and has recently been suggested to be involved in toll-like receptor (TLR) 2/4 signaling. Activation of TLR7 on pDCs results in an upregulation of pro-inflammatory cytokines, such as type I interferons (IFN-I), and has been implicated in several autoimmune and inflammatory diseases, but the role of XBP1 in this process remains unknown. Here, we show that signaling via TLR7 leads to an upregulation of XBP1 and IFNα-production. XBP1 mRNA expression levels positively correlated with the production of IFNα, while blocking of XBP1 mRNA splicing significantly reduced mRNA transcripts of IFNα. In conclusion, these data suggest a central role of XBP1 in TLR7-induced IFNα production and identify XBP1 as a potential novel therapeutic target in IFNα-driven autoimmune and inflammatory diseases.

Sex Differences in Plasmacytoid Dendritic Cell Levels of IRF5 Drive Higher IFN-α Production in Women.

Increased IFN-α production contributes to the pathogenesis of infectious and autoimmune diseases. Plasmacytoid dendritic cells (pDCs) from females produce more IFN-α upon TLR7 stimulation than pDCs from males, yet the mechanisms underlying this difference remain unclear. In this article, we show that basal levels of IFN regulatory factor (IRF) 5 in pDCs were significantly higher in females compared with males and positively correlated with the percentage of IFN-α-secreting pDCs. Delivery of recombinant IRF5 protein into human primary pDCs increased TLR7-mediated IFN-α secretion. In mice, genetic ablation of the estrogen receptor 1 (Esr1) gene in the hematopoietic compartment or DC lineage reduced Irf5 mRNA expression in pDCs and IFN-α production. IRF5 mRNA levels furthermore correlated with ESR1 mRNA levels in human pDCs, consistent with IRF5 regulation at the transcriptional level by ESR1. Taken together, these data demonstrate a critical mechanism by which sex differences in basal pDC IRF5 expression lead to higher IFN-α production upon TLR7 stimulation in females and provide novel targets for the modulation of immune responses and inflammation.

Hemodynamic assessment of paravalvular aortic regurgitation after TAVI: estimated myocardial supply-demand ratio and cardiovascular mortality.

A relevant (at least moderate) paravalvular regurgitation (PAR) after transcatheter aortic valve implantation (TAVI) is found in up to 20% of cases and associated with increased mortality. The ratio of the diastolic over the systolic pressure time integral (DPTI:SPTI) has been proposed to reflect an estimate of myocardial oxygen supply versus demand and the propensity for myocardial ischemia. We have now evaluated the potential of this ratio to predict PAR-associated cardiovascular mortality after TAVI, retrospectively analyzing data from 167 consecutive TAVI patients. PAR was graded angiographically, and the myocardial supply-demand ratio was estimated from the planimetric integration of the diastolic and systolic pressure-time area (DPTI and SPTI), respectively. PAR was observed in 113 patients (67%) and angiographically graded as mild in 89 (78.8%), moderate in 21 (18.6%) or moderate to severe in 3 (2.7%) cases. The DPTI:SPTI ratio decreased with increasing Sellers grade of PAR (P < 0.001). A DPTI:SPTI of ≤0.7 predicted cardiovascular mortality (area under the curve = 0.96). Cardiovascular mortality at 30 days and 1 yr was increased in patients with DPTI:SPTI ≤ 0.7 over those with DPTI:SPTI > 0.7 (42 vs. 2% and 63 vs. 3%, respectively; P < 0.001). In conclusion, DPTI:SPTI provides an excellent cutoff value of ≤0.7 for the prediction of PAR-associated mortality.

Incidence, predictors, origin and prevention of early and late neurological events after transcatheter aortic valve implantation (TAVI): a comprehensive review of current data.

Transcatheter aortic valve implantation (TAVI) is a novel treatment option for patients with severe, symptomatic aortic valve stenosis considered inoperable or at high risk for surgical aortic valve replacement. Despite rapid adoption of this technology into clinical application, however, recent randomized controlled clinical trials have raised safety concerns regarding an increased risk of neurological events with TAVI compared to both medical treatment and conventional, surgical aortic valve replacement. Moreover, neuro-imaging studies have revealed an even higher incidence of new, albeit clinically silent cerebral lesions as a surrogate for procedural embolization. In this article, we review currently available data on the incidence, timing, predictors, prognostic implications and potential mechanisms of neurological events after TAVI.

Vulnerable plaque: detection and management.

Because most myocardial infarctions result from the rupture of a plaque that did not significantly compromise the coronary lumen before the event, experts widely accept that the morphology, composition, and degree of inflammation of a coronary atherosclerotic plaque is more important than the degree of luminal stenosis. Two depicting examples are the concentric, calcified lesion that shows significant luminal stenosis but is stable because of the stabilizing clasp of calcification. In contrast, a smaller but inflamed thin fibrous cap atheroma with a big lipid/necrotic core may rupture and cause an immediate fatal coronary occlusion.

Transfemoral transcatheter aortic valve implantation in patients with end-stage renal disease and kidney transplant recipients.

Transcatheter aortic valve implantation (TAVI) has evolved to a treatment of choice in high-risk patients and is therefore ideal for patients with advanced chronic kidney disease, as patients with end-stage renal disease and kidney transplant recipients. Especially, outcome of this special patient group is very important. 22 patients with chronic kidney disease stage 5 undergoing intermittent hemodialysis treatment (CKD 5D) and 8 kidney transplant recipients (KT) with severe aortic valve stenosis underwent transfemoral TAVI. TAVI was successfully performed in all patients. Postinterventional acute kidney injury (AKI) occurred in four kidney transplant recipients (KDIGO grade 1: n = 3, grade 3: n = 1) but creatinine/eGFR returned to baseline values in all patients. Short-term (30-day) mortality was 3% (1 patient in CKD 5D group). KT had a higher 2-year mortality than CKD5D patients (31% vs. 53%; p = 0.309), and cause of death was non-cardiac because of sepsis in all cases. The amount of contrast medium during TAVI was not associated with the development of acute kidney injury. TAVI is feasible in patients with CKD5D and in KT. Postinterventional AKI in these patients is often mild and does not impact renal function at day 30, while infection/ sepsis is the leading cause of mid-term mortality.

No protection of heart, kidneys and brain by remote ischemic preconditioning before transfemoral transcatheter aortic valve implantation: Interim-analysis of a randomized single-blinded, placebo-controlled, single-center trial.

BACKGROUND: Remote ischemic preconditioning (RIPC) reduces myocardial injury and improves clinical outcome in patients undergoing coronary revascularization, but only in the absence of propofol-anesthesia. We investigated whether RIPC provides protection of heart, kidneys and brain and improves outcome in patients undergoing transfemoral transcatheter aortic valve implantation (TF-TAVI). METHODS: Patients undergoing TF-TAVI were randomized to receive RIPC (3cycles of 5min left upper arm ischemia and 5min reperfusion) or placebo. The primary endpoint was myocardial injury, reflected by the area under the curve for serum troponin I concentrations (AUC-TnI) over the first 72h. Secondary endpoints included the incidences of periprocedural myocardial infarction, delayed gadolinium enhancement on postprocedural cardiac MRI, acute kidney injury, periprocedural stroke, and the incidence and volume of new lesions on postprocedural cerebral MRI. All-cause and cardiovascular mortality and major adverse cardiac and cerebrovascular events (MACCE) were assessed over 1-year follow-up. A prespecified interim-analysis was performed after the last patient had completed 1-year follow-up (NCT02080299). RESULTS: 100 consecutive patients were enrolled between September 2013 and June 2015. There were no significant between-group differences in the primary endpoint of peri-interventional myocardial injury (ratio RIPC/placebo AUC-TnI: 0.87, 95% CI: 0.57-1.34, p=0.53) or the secondary endpoints of cardiac, renal and cerebral impairment. There was no significant treatment effect in subgroup-analyses of patients undergoing cardiac or cerebral MRI. Mortality and MACCE did not differ. No RIPC-related adverse events were observed. CONCLUSIONS: RIPC did neither protect heart, kidneys and brain nor improve clinical outcome in patients undergoing TF-TAVI.

Kinetics and Signal Activation Properties of Circulating Factor(s) From Healthy Volunteers Undergoing Remote Ischemic Pre-Conditioning.

Although remote ischemic pre-conditioning (RIPC) reduced infarct size in animal experiments and proof-of-concept clinical trials, recent phase III trials failed to confirm cardioprotection during cardiac surgery. Here, we characterized the kinetic properties of humoral factors that are released after RIPC, as well as the signal transduction pathways that were responsible for cardioprotection in an ex vivo model of global ischemia reperfusion injury. Venous blood from 20 healthy volunteers was collected at baseline and 5 min, 30 min, 1 h, 6 h, and daily from 1 to 7 days after RIPC (3 × 5/5 min upper-limb ischemia/reperfusion). Plasma-dialysates (cut-off: 12 to 14 kDa; dilution: 1:20) were infused into Langendorff-perfused mouse hearts subjected to 20/120 min global ischemia/reperfusion. Infarct size and phosphorylation of signal transducer and activator of transcription (STAT)3, STAT5, extracellular-regulated kinase 1/2 and protein kinase B were determined. In a subgroup of plasma-dialysates, an inhibitor of STAT3 (Stattic) was used in mouse hearts. Perfusion with baseline-dialysate resulted in an infarct size of 39% of ventricular mass (interquartile range: 36% to 42%). Perfusion with dialysates obtained 5 min to 6 days after RIPC significantly reduced infarct size by ∼50% and increased STAT3 phosphorylation beyond that with baseline-dialysate. Inhibition of STAT3 abrogated these effects. These results suggest that RIPC induces the release of cardioprotective, dialyzable factor(s) within 5 min, and that circulate for up to 6 days. STAT3 is activated in murine myocardium by RIPC-induced human humoral factors and is causally involved in cardioprotection.

Quantification and characterisation of released plaque material during bioresorbable vascular scaffold implantation into right coronary artery lesions by multimodality intracoronary imaging.

AIMS: We aimed to compare intravascular ultrasound with virtual histology (VH-IVUS), optical coherence tomography (OCT) and near-infrared spectroscopy (NIRS) for their ability to quantify the true amount and characterise the nature of released plaque material during bioresorbable vascular scaffold (BVS) implantation into right coronary artery (RCA) lesions using a distal occlusion and aspiration device. METHODS AND RESULTS: Seventeen patients underwent BVS implantation into the right coronary artery under distal protection with intracoronary imaging using VH-IVUS, OCT and NIRS. The amount of released plaque material and its lipid content (LC) were determined. Necrotic core volume and minimal fibrous cap thickness correlated with the amount of released plaque material (r=0.80 and r=-0.65, respectively) and its LC (r=0.75 and r=-0.78, respectively), but not maximal lipid core burden index (LCBI). OCT-identified thin-cap fibroatheromata (TCFA) were associated with the greatest amount of released plaque material compared to non-TCFA (46.8 [29.0;49.2] mg vs. 14.2 [11.3;19.4] mg; p=0.003) and LC (4.4 [4.0;4.8] mg vs. 2.0 [1.8;2.5] mg; p=0.000). CONCLUSIONS: VH-IVUS and OCT but not NIRS parameters quantify and characterise the amount of released plaque material. TCFA is associated with the highest amount of released plaque material and may therefore benefit from the use of protection devices.

Risk Assessment of Patients Undergoing Transfemoral Aortic Valve Implantation upon Admission for Post-Interventional Intensive Care and Surveillance: Implications on Short- and Midterm Outcomes.

BACKGROUND: Several studies have found that standard risk scores inaccurately reflect risk in TAVI cohorts. The assessment of mortality risk upon post-interventional ICU admission is important to optimizing clinical management. This study sought to determine outcomes and factors affecting mortality in patients admitted to the intensive care unit (ICU) after transcatheter aortic valve implantation (TAVI), and to analyze and compare the predictive values of SAPS II and EuroSCORE. METHODS AND FINDINGS: 214 consecutive patients treated with transfemoral TAVI (2006-2012) admitted to the ICU in an academic tertiary-care university hospital, were included in this retrospective data analysis. The overall 30-day mortality rate was 7%. Non-survivors at 30-days and survivors showed differences in the rates of catecholamine therapy upon ICU admission (93 vs. 29%; p<0.001), stroke (20 vs. 1%;p<0.001), sepsis (27 vs. 2%;p<0.001), kidney injury (83 vs. 56%; log-rank p<0.001), catecholamine therapy (88 vs. 61%;log-rank p<0.001) and vascular complications (60 vs. 17%; p<0.001). Mean SAPS II score and predicted mortality were higher in non-survivors (38.1±7.0 vs. 29.9±6.2;p<0.001 and 23.1±11.7 vs. 10.5±8.2;p<0.001, retrospectively), whereas the logistic EuroSCORE could not discriminate between the groups (p = 0.555). Among the biochemical parameters, the maximum values of creatinine, procalcitonin, and troponin I during the first 48 h after ICU admission were significantly higher in non-survivors. Multivariate analysis of baseline characteristics and complications associated with two-year mortality showed no significant results. CONCLUSIONS: The SAPS II is a good tool for estimating ICU mortality immediately after performing the TAVI procedure and provides valuable information for other known predictors of mortality.

Myocardial injury during transfemoral transcatheter aortic valve implantation: an intracoronary Doppler and cardiac magnetic resonance imaging study.

AIMS: Myocardial injury reflected by a post-procedural increase of serum troponin I (TnI) occurs frequently during transcatheter aortic valve implantation (TAVI). It is potentially caused by intraprocedural hypotension, periprocedural coronary microembolisation and post-procedural (para)valvular leakages (PVLs). We invasively assessed coronary flow dynamics including coronary flow velocity reserve (CFVR), embolic high-intensity transient signals (HITS) as well as rapid pacing induced hypotension and post-procedural PVLs to determine their contribution to post-procedural TnI increases. METHODS AND RESULTS: In 15 transfemoral TAVI patients, TnI was measured serially, and cardiac MRIs with late gadolinium enhancement (LGE) were performed pre- and post-interventionally. There were no significant correlations between coronary flow dynamics, CFVR and the area under the curve (AUC) of TnI over 72 hours. Despite the detection of HITS in all patients and during all procedural steps, there was also no correlation between the amount of HITS and the AUC of TnI. However, there were positive correlations between the duration of rapid pacing as well as the time of subsequent blood pressure recovery and the AUC of TnI. Both LGE and more than mild PVL were observed in a single case only. CONCLUSIONS: Myocardial injury after TAVI appears to be related more to hypoperfusion-induced ischaemia than to periprocedural microembolisation.

Silent cerebral ischemia after thoracic endovascular aortic repair: a neuroimaging study.

BACKGROUND: The risk of clinically apparent, periprocedural stroke after thoracic endovascular aortic repair (TEVAR) due to dislodgement and embolization of aortic debris from intravascular manipulation of guidewires, catheters, and large-bore delivery systems ranges between 2% and 6% and has been associated with increased postoperative mortality. The rate of clinically silent cerebral ischemia is yet unknown, but may be even higher. METHODS: Nineteen patients (13 male, 6 female) who underwent TEVAR were included into this descriptive study. Periprocedural apparent and silent cerebral ischemia was assessed by daily clinical neurologic assessment and serial cerebral diffusion-weighted magnetic resonance imaging (DW-MRI) at baseline and 5 days (median, interquartile range: 3.5) after the procedure. RESULTS: The TEVAR was successful in all patients without immediate clinically apparent neurologic deficits. Postinterventional cerebral DW-MRI detected a total of 29 new foci of restricted diffusion in 12 of 19 TEVAR patients (63%). Lesions were usually multiple (1 to 6 lesions per patient) and ranged in size between 15 mm3 and 300 mm3; 16 lesions were found in the left hemisphere, 13 lesions in the right hemisphere. Overstenting of the left subclavian artery was performed in 8 cases, but was not associated with lateralization of lesions. There were no additional apparent neurologic events during the in-hospital period. CONCLUSIONS: Thoracic endovascular aortic repair resulted in a high incidence of new foci of restricted diffusion on cerebral DW-MRI in a pattern suggestive of periprocedural embolization. Although multiple lesions per patients were found, these lesions were not associated with apparent neurologic deficits during the in-hospital period. Further developments in TEVAR should be directed toward reducing the risk of periprocedural cerebral embolization.

Preparatory balloon aortic valvuloplasty during transcatheter aortic valve implantation for improved valve sizing.

OBJECTIVES: This study sought to evaluate whether supra-aortic angiography during preparatory balloon aortic valvuloplasty (BAV) improves valve sizing. BACKGROUND: Current recommendations for valve size selection are based on annular measurements by transesophageal echocardiography and computed tomography, but paravalvular aortic regurgitation (PAR) is a frequent problem. METHODS: Data of 270 consecutive patients with either conventional sizing (group 1, n = 167) or balloon aortic valvuloplasty-based sizing (group 2, n = 103) were compared. PAR was graded angiographically and quantitatively using several hemodynamic indices. RESULTS: PAR was observed in 113 patients of group 1 and 41 patients of group 2 (67.7% vs. 39.8%, p < 0.001). More than mild PAR was found in 24 (14.4%) patients of group 1 and 8 (7.8%) patients of group 2. According to pre-interventional imaging, 40 (39%) patients had a borderline annulus size, raising uncertainty regarding valve size selection. Balloon sizing resulted in selection of the bigger prosthesis in 30 (29%) and the smaller prosthesis in the remaining patients, and only 1 of these 40 patients had more than mild PAR. As predicted by the hemodynamic indices of PAR, mortality at 30 days and 1 year was less in group 2 than in group 1 (5.8% vs. 9%, p = 0.2 and 10.6% vs. 20%, p = 0.01). CONCLUSIONS: Preparatory balloon aortic valvuloplasty during transcatheter aortic valve implantation improves valve size selection, reduces the associated PAR, and increases survival in borderline cases.