Single-cell profiling reveals inflammatory polarization of human carotid versus femoral plaque leukocytes

Femoral atherosclerotic plaques are less inflammatory than carotid plaques histologically, but limited cell-level data exist regarding comparative immune landscapes and polarization at these sites. We investigated intraplaque leukocyte phenotypes and transcriptional polarization in 49 patients undergoing femoral (n = 23) or carotid (n = 26) endarterectomy using single-cell RNA-Seq (scRNA-Seq; n = 13), flow cytometry (n = 24), and IHC (n = 12). Comparative scRNA-Seq of CD45+-selected leukocytes from femoral (n = 9; 35,265 cells) and carotid (n = 4; 30,655 cells) plaque revealed distinct transcriptional profiles. Inflammatory foam cell-like macrophages and monocytes comprised higher proportions of myeloid cells in carotid plaques, whereas noninflammatory foam cell-like macrophages and LYVE1-overexpressing macrophages comprised higher proportions of myeloid cells in femoral plaque (P < 0.001 for all). A significant comparative excess of CCR2+ macrophages in carotid versus plaque was observed by flow cytometry in a separate validation cohort. B cells were more prevalent and exhibited a comparatively antiinflammatory profile in femoral plaque, whereas cytotoxic CD8+ T cells were more prevalent in carotid plaque. In conclusion, human femoral plaques exhibit distinct macrophage phenotypic and transcriptional profiles as well as diminished CD8+ T cell populations compared with human carotid plaques.

More than neutrophils: Lin(+)Ly6G(+)IL-5Rα(+) multipotent myeloid cells (MMCs) are dominant in normal murine bone marrow and retain capacity to differentiate into eosinophils and monocytes

Bone marrow is a hematopoietic site harboring multiple populations of myeloid cells in different stages of differentiation. Murine bone marrow eosinophils are traditionally identified by Siglec-F(+) staining using flow cytometry, whereas neutrophils are characterized by Ly6G(+) expression. However, using flow cytometry to characterize bone marrow hematopoietic cells in wild-type mice, we found substantial gray areas in identification of these cells. Siglec-F(+) mature eosinophil population constituted only a minority of bone marrow Lin(+)CD45(+) pool (5%). A substantial population of Siglec-F(-) cells was double positive for neutrophil marker Ly6G and eosinophil lineage marker, IL-5Rα. This granulocyte population with mixed neutrophil and eosinophil characteristics is typically attributable to neutrophil pool based on neutral granule staining and expression of Ly6G and myeloid peroxidase. It is distinct from Lineage(-) myeloid progenitors or Siglec-F(+)Ly6G(+) maturing eosinophil precursors, and can be accurately identified by Lineage(+) staining and positive expression of markers IL-5Rα and Ly6G. At 15-50% of all CD45(+) hematopoietic cells in adult mice (percentage varies by sex and age), this is a surprisingly dominant population, which increases with age in both male and female mice. RNA-seq characterization of these cells revealed a complex immune profile and the capacity to secrete constituents of the extracellular matrix. When sorted from bone marrow, these resident cells had neutrophilic phenotype but readily acquired all characteristics of eosinophils when cultured with G-CSF or IL-5, including expression of Siglec-F and granular proteins (Epx, Mbp). Surprisingly, these cells were also able to differentiate into Ly6C(+) monocytes when cultured with M-CSF. Herein described is the discovery of an unexpected hematopoietic flexibility of a dominant population of multipotent myeloid cells, typically categorized as neutrophils, but with the previously unknown plasticity to contribute to mature pools of eosinophils and monocytes.

Beyond Il-5: Metabolic Reprogramming and Stromal Support Are Prerequisite for Generation and Survival of Long-Lived Eosinophil

Eosinophils play surprisingly diverse roles in health and disease. Accordingly, we have now begun to appreciate the scope of the functional and phenotypic heterogeneity and plasticity of these cells. Along with tissue-recruited subsets during inflammation, there are tissue resident eosinophil phenotypes with potentially longer life spans and less dependency on IL-5 for survival. Current models to study murine eosinophils ex vivo rely on IL-5-sustained expansion of eosinophils from bone marrow hematopoietic progenitors. Although it does generate eosinophils (bmEos) in high purity, such systems are short-lived (14 days on average) and depend on IL-5. In this report, we present a novel method of differentiating large numbers of pure bone marrow-derived eosinophils with a long-lived phenotype (llEos) (40 days on average) that require IL-5 for initial differentiation, but not for subsequent survival. We identified two key factors in the development of llEos: metabolic adaptation and reprogramming induced by suppressed nutrient intake during active differentiation (from Day 7 of culture), and interaction with IL-5-primed stromal cells for the remainder of the protocol. This regimen results in a higher yield and viability of mature eosinophils. Phenotypically, llEos develop as Siglec-F(+)Ly6G(+) cells transitioning to Siglec-F(+) only, and exhibit typical eosinophil features with red eosin granular staining, as well as the ability to chemotax to eotaxin Ccl11 and process fibrinogen. This culture system requires less reagent input and allows us to study eosinophils long-term, which is a significant improvement over IL-5-driven differentiation protocols. Moreover, it provides important insights into factors governing eosinophil plasticity and the ability to assume long-lived IL-5-independent phenotypes.

Comparison between optical frequency domain imaging and intravascular ultrasound in PCI guidance for Biolimus A9 eluting stent implantation

Background

It has been reported that intravascular ultrasound (IVUS) guided PCI reduced a risk of major adverse cardiac event compared to conventional angiography guided PCI, while comparison between IVUS-guided and optical frequency domain imaging (OFDI)-guided PCI specifically in long-term clinical outcomes (&gt;1 year) has been unexplored.

Purpose

We sought to compare imaging surrogates at 8 months and clinical outcomes beyond 1 year after drug-eluting stent implantation between IVUS and OFDI guidance.

Methods

The MISTIC-1 is a prospective, multi-centre, single-blinded, randomised-controlled, non-inferiority trial comparing OFDI-guided and IVUS-guided PCI using Biolimus A9 eluting Nobori stent. We enrolled patients with stable coronary artery disease who have symptoms or clinically relevant myocardial ischemia. Stent landing zones were selected in the most normal looking sites with largest lumen and without percentage plaque area &gt;50% in IVUS group while without lipidic plaque of &gt;2 quadrants or suggestive thin-cap fibroatheroma in OFDI group. Stent sizing was based on external elastic lamina (EEL) in IVUS group, while by taking 10% or 0.25mm larger than mean lumen diameter at reference sites in OFDI group. Stent optimisation with in-stent minimum lumen area ≥80% of the average lumen area at proximal and distal reference sites was encouraged in both groups. Primary efficacy endpoint is in-segment minimum lumen area (MLA) assessed by OFDI at 8 months. Secondary safety endpoint is a composite of cardiovascular death, target vessel myocardial infarction, or target lesion revascularisation. Based on the assumption that mean in-segment MLA at follow-up was 4.5mm2 with a standard deviation of 2.0mm2 in the control (IVUS) group and a non-inferiority limit of 1.2mm2 for OFDI group, sample size was estimated as 48 cases in each group with 5% type I error and 90% statistical power.

Results

Since June-2014 and August-2016, we prospectively enrolled 109 patients (mean age 70 years, male 78%) with 126 lesions. Baseline patient and lesion characteristics were well balanced and average nominal size and length of stent used did not differ between OFDI-guided and IVUS-guided PCI (3.0 and 19.1mm vs. 3.1 and 19.3mm, respectively). Post-procedural minimum stent area was 6.24mm2 in OFDI group and 6.72mm2 in IVUS group (p=0.20). At 8-month follow-up, in-segment MLA was 4.56mm2 in OFDI group and 4.13mm2 in IVUS group (P for non-inferiority &lt;0.001). During the follow-up (median 4.5 years [1654 days]), incidence rates of major adverse cardiac event were comparable between the two groups (7.4% in OFDI group and 7.3% in IVUS group, hazard ratio 0.96, 95% CI 0.24–3.83, p=0.95). No definite or probable stent thrombosis were documented in both groups.

Conclusion

OFDI-guided PCI demonstrated comparable results in achieving satisfactory imaging surrogates as well as long-term clinical outcomes after newer generation DES implantation as compared to IVUS-guided PCI.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Suzuken Memorial Foundation

Epithelial cytokine IL-33 and sub-epithelial matrix protein tenascin C compartmentalize eosinophil phenotype and function

In allergic inflammation, eosinophils interacting with epithelial barriers experience exposure to epithelial cytokines and the extracellular milieu of airway remodeling. To better understand eosinophil activation biology in allergic tissue, we modeled the synergistic and opposing regulation of naïve eosinophils by both sub-epithelial extracellular matrix protein tenascin C (TNC), a key player in epithelial regeneration, and IL-33, an epithelial damage-induced cytokine. IL-5-differentiated bone marrow-derived murine eosinophils were cultured with recombinant TNC (25 ug/ml), IL-33 (100 ng/ml), or both for 24 hours and profiled by flow cytometry, qPCR, and DiffQuick staining. IL-33 alone significantly induced IL-4 and integrin CD11b expression, which was antagonized by co-culture with TNC. Conversely, TNC alone significantly promoted CD34 and intra-epithelial docking integrin CD103 expression, which was suppressed by IL-33 addition. Both treatments synergized in promoting expression of trans-epithelial migration marker CD11c. TNC promoted resident morphology while IL-33 induced an activated phenotype. This illustrates how microenvironmental cues may progressively shape eosinophils trafficking from sub-epithelial space across epithelial barriers.

Hyperglycemia impairs tolerance and promotes allergic inflammation in mouse models of asthma

Glucose is a key source of energy in systemic and cellular metabolism and has known pro-inflammatory properties. Metabolic disorders (diabetes, insulin resistance) associate with asthma and other allergic diseases. This study sought to understand the role of hyperglycemia in the allergic response. First, we injected fasted Balbc/J mice intraperitoneally (i.p.) with 2g/kg dextrose to test whether hyperglycemia promotes antigen sensitization. Within one hour of injection, we detected a rapid increase in blood glucose levels followed by an increase in expression of inflammatory markers Il1β, Tslp, and Cxcl9 in peritoneal tissue. Concurrently, MHCII+ cells infiltrated the peritoneum. Control experiments showed that inflammatory responses were not due to hyperosmotic effects. To determine whether glucose promotes allergic response, we sensitized mice to chicken egg ovalbumin (OVA) using either alum (standard adjuvant), dextrose, or a vehicle control. Both alum/OVA and dextrose/OVA treated mice mounted lung allergic inflammation in response to inhaled OVA antigen. Dextrose/OVA mice had OVA-specific IgE production similar to alum/OVA group, demonstrating glucose’s ability to promote sensitization. Total cellular infiltrates, bronchoalveolar lavage (BAL) eosinophils, and lung expression of IL-4, IL-13 and IL-33 in dextrose-sensitized mice were equal to or surpassing allergic inflammatory responses in mice given standard adjuvant. Finally, in a separate mouse tolerance model we demonstrated that hyperglycemia impairs development of tolerogenic response to innocuous OVA antigen. These results demonstrate a potentially critical role for glucose dysregulation in loss of tolerance and promotion of allergy.

Siglec-F-negative resident eosinophils represent an unexpectedly dominant population in homeostatic murine bone marrow

Bone marrow, while known to be a hematopoietic site for eosinophils, also harbors resident populations of these cells. Identification of such resident eosinophils typically requires flow cytometry-assisted sorting, with Siglec-F as a key marker for identification of murine eosinophils. At baseline, we found that bone marrow resident eosinophils described as Siglec-F(+) constitute about 5% of CD45 cells. Although this identifies mature eosinophils, it may not be sufficient to represent all resident phenotypes. Using sequencing and FACS sorting approaches, we found that the Siglec-F(+) population represented only a minority of the resident eosinophil pool. Rather, we identified a lineage-positive population of IL-5Ra(+)Ly6G(+) but Siglec-F(−) cells distinct from lineage-negative EoPs (eosinophil progenitors). At 40% of all CD45(+) hematopoietic cells in adult mice, this bone marrow resident population dwarfs the Siglec-F(+) eosinophil pool. When sorted from bone marrow homogenates and treated with IL-5, these resident cells acquired all characteristics of mature eosinophils, including expression of Siglec-F and granular proteins (EPX, MPO). These tissue residents may play critical homeostatic roles in normal murine bone marrow and should be accounted for in studies of eosinophil biology.

P1901Use of direct thrombin inhibitor on the day of atrial fibrillation ablation decreases incidence of silent cerebral ischemia detected by magnetic resonance imaging

Background

There is increasing evidence to use direct oral anticoagulants (DOACs) in atrial fibrillation (AF) ablation. Uninterrupted use of DOACs is recommended for peri-procedural anticoagulation; the ways of choosing and/or using DOACs depend on physicians' decisions and preferences. Uninterrupted dabigatran (DAB), a direct thrombin inhibitor, reportedly decreased the risk of major bleeding (MB) in AF ablation, compared to uninterrupted warfarin (NEJM 2017; 376:1627). Among DOACs, only regular-dose of DAB (150 mg b.i.d.), showed superiority to warfarin for preventing ischemic thromboembolism (TE) in patients with non-valvular AF, implicating the powerful anti-thrombotic agent. DAB may decrease the potential risk of procedure-related TE.

Purpose

To evaluate whether use of DAB on the day of AF ablation decreases the prevalence of silent cerebral ischemia (SCI) detected by magnetic resonance imaging (MRI).

Methods

414 AF patients on DOACs were enrolled and admitted on the day before AF ablation. Among 354 patients on factor Xa inhibitors (rivaroxaban, apixaban, and edoxaban), the original DOACs were switched to DAB (150 mg b.i.d.) on the day of the procedure in 172 patients (Group D); the treatment remained unchanged in 182 patients (Group non-D). In both groups, DOACs were continuously used throughout the procedure. After propensity-score matching, procedure-related parameters/events and the incidence of MRI-detected SCI were compared between Group D (n=134) and Group non-D (n=134). These parameters in patients originally taking DAB, used without interruption during the procedure (uninterrupted DAB, n=55), were also compared to Group D (n=55) after propensity-score matching.

Results

Baseline activated clotting time (ACT) before initial heparin injection was increased in Group D vs. Group-non-D (179±25* vs. 146±23 sec, *p<0.05 vs. Group non-D). The time to achieve optimal ACT (>300 sec) was shorter in Group D (34±29* vs. 43±32 min). The amounts of heparin needed to achieve optimal ACT and the total amount of heparin used during the procedure were unchanged between Group D and Group non-D. The incidence of SCI decreased in Group D (13.1%* vs. 21.9%), suggesting the potential anti-thrombotic efficacy of DAB. No MB or symptomatic TE events were observed in either group. Baseline ACT, the time to achieve ACT >300 sec, and the incidence of SCI in Group D were comparable to those in uninterrupted DAB (183±38 vs. 181±32 sec, 39±31 vs. 42±28 min, and 14.5% vs. 16.4%, respectively). No MB or symptomatic TE events were observed either in Group D or uninterrupted DAB.

Conclusions

Temporarily switching to DAB from the other DOACs and using it on the day of procedure enable us to achieve optimal ACT quickly and decrease the incidence of SCI, showing similar potential anti-thrombotic efficacy to uninterrupted DAB. Use of DAB on the day of AF ablation also benefits from the availability of its antidote in the case of MB during the procedure.

P3388Five year outcomes of patients with lipid rich plaque detected three-dimensional Integrated-Backscatter intravascular ultrasound (IB-IVUS) in target lesion after second generation DES implantation

Background

Elective percutaneous coronary intervention (PCI) using second generation drug-eluting stent (DES) has been dramatically reduced restenosis rate. Recently, it has been reported that plaque characterization in nontarget lesion is associated with cardio-vascular events in ischemic heart disease patients undergoing elective PCI. However, it is unclear whether plaque characterization in target lesion is predictor of MACEs (major adverse cardiac events) after elective PCI.

Purposes

The aim of this study is whether plaque characterization detected integrated-backscatter intravascular ultrasound (IB-IVUS) in the target lesion is associated with MACEs in patients with PCI after second generation DES implantation.

Methods and results

Of 700 patients with ischemic heart disease, 552 patients were excluded for chronic totally occlusion, severe calcification hindering precise intracoronary imaging, tortuous lesions, ostial or left main stem lesions and ST-elevated myocardial infarction patients. Finally, 148 consecutive patients who consented to repeated IB-IVUS prior to undergoing elective PCI were recruited in the study.Plaque characterization in target lesion was identified for three-dimensional IB-IVUS technology using the mechanical IVUS catheter (ViewIT, 40 MHz, 2.5 Fr; Terumo, Tokyo, Japan). The median of percentage lipid volume in all target lesions was 47.6%. Furthermore, lipid rich plaque (LRP) group was defined as the lesions consisting of percentage lipid volume greater than the median. And, non-lipid rich plaque (non-LRP) group was defined as the lesions consisting of percentage lipid volume less than the median. MACEs were defined as cardiovascular death, target vessel myocardial infarction, target lesion revascularization and stent thrombosis. The median of follow up period was 60 months. Of the 148 patients, 106 patients had stable angina pectoris. The remaining 42 patients are acute coronary syndrome (NSTE-ACS). 74 patients were classified LRP groups and 74 patients were non-LRP groups. No significant differences were observed between the two groups with respect to age, sex and coronary risk factors. While plaque and vessel volume were greater in the LRP group (216.9±116.3mm3, p<0.001) than non-LRP group (322.5±144.0mm3, p p<0.001). Remodeling index was greater in LRP group (1.02±0.18) than non-LRP group (0.93±0.18, p<0.003). Although MACEs were no significant differences between the two groups, the number of MACEs tend to be more in patients with LRP group (8.1±27.4%) than small lipid group (2.7±16.3, p<0.147). Especially, cardiac death tend to be more in LRP group (6.7±25.2% than non-LRP group (1.3±11.6, p<0.096).

Conclusions

In conclusion, lipid rich plaque detected by three dimensional IB-IVUS system in target lesion with patients undergoing elective PCI may be associated with clinical outcomes for five years after second generation DES implantation.

Acknowledgement/Funding

None

Induced hyperglycemia promotes sensitization and exacerbates allergic inflammation in a mouse model of asthma

Glucose is a key source of energy in systemic and cellular metabolism and has known pro-inflammatory properties. It has recently been acknowledged that associations exist between metabolic disorders (diabetes, insulin resistance, obesity), asthma and other allergic diseases. As the prevalence of both metabolic and allergic disorders increases, it is important to understand how metabolism can influence the development of allergy. First, we injected fasted wild type Balbc/J mice intraperitoneally (i.p.) with 2g/kg dextrose (standard hyperglycemic challenge) to test whether hyperglycemia promotes inflammation favoring antigen sensitization. Within one hour of injection, we detected a rapid increase in blood glucose levels (up to 130 mg/dL) followed by an increase in Il1β, Tslp, Cxcl9, and Siglec5 gene expression in the peritoneal tissue compared to vehicle controls. Within 2 hours post injection, IL-1β protein was detected in peritoneal cellular infiltrate. In order to determine whether glucose-induced inflammation promotes allergic response, we sensitized mice by i.p. to chicken egg ovalbumin (OVA) using either alum (standard adjuvant), dextrose or vehicle control. Both alum/OVA and dextrose/OVA mounted lung allergic inflammation in response to inhaled OVA antigen. Dextrose/OVA mice had OVA-specific IgE production similar to alum/OVA group, demonstrating ability to promote sensitization. Remarkably, total cellular infiltrates, bronchoalveolar lavage eosinophils, lung expression of IL-4, IL-13 and IL-33 in dextrose-sensitized mice were equal or surpassing allergic inflammatory responses in mice given standard adjuvant. These results demonstrate a potentially critical role for glucose in promotion of allergy.

Cycloartenyl ferulate, a component of rice bran oil-derived gamma-oryzanol, attenuates mast cell degranulation

IgE-targeting therapy could provide significant progress in the treatment of allergic inflammation. In this study, we examined the effect of cycloartenyl ferulate (cycloartenol ferulic acid ester; CAF), a natural product from rice bran oil-derived gamma-oryzanol, on allergic reaction. When CAF and gamma-oryzanol were injected intradermally with anti-DNP IgE into the dorsal skin of rats, the passive cutaneous anaphylaxis reaction induced by DNP-HSA was attenuated. CAF and gamma-oryzanol also inhibited the degranulation of DNP-IgE sensitized RBL-2H3 mast cells stimulated with anti-DNP-HSA. IgE conjugated with CAF could not be detected by anti-IgE antibody in the ELISA analysis. Although incubation of IgE with CAF did not decrease the amount of IgE, it was possible to precipitate IgE by centrifugation. These results demonstrate that CAF captures IgE, prevents it from binding to FcepsilonRI, and attenuates mast cell degranulation.

Anti-inflammatory effects of phytosteryl ferulates in colitis induced by dextran sulphate sodium in mice

BACKGROUND AND PURPOSE

We have recently reported that phytosteryl ferulates isolated from rice bran inhibit nuclear factor-kappaB (NF-kappaB) activity in macrophages. In the present study, we investigated the effect of gamma-oryzanol (gamma-ORZ), a mixture of phytosteryl ferulates, cycloartenyl ferulate (CAF), one of the components of gamma-ORZ, and ferulic acid (FA), a possible metabolite of gamma-ORZ in vivo, on a model of colitis in mice.

EXPERIMENTAL APPROACH

We induced colitis with dextran sulphate sodium (DSS) in mice and monitored disease activity index (DAI), histopathology score, tissue myeloperoxidase (MPO) activity, mRNA expressions of cytokines and COX-2, colon length, antioxidant potency and NF-kappaB activity in colitis tissue.

KEY RESULTS

Both DAI and histopathology score revealed that DSS induced a severe mucosal colitis, with a marked increase in the thickness of the muscle layer, distortion and loss of crypts, depletion of goblet cells and infiltration of macrophages, granulocytes and lymphocytes. MPO activity, pro-inflammatory cytokines and COX-2 levels, NF-kappaB p65 nuclear translocation and inhibitory protein of nuclear factor-kappaB-alpha degradation levels were significantly increased in DSS-induced colitis tissues. gamma-ORZ (50 mg kg(-1) day(-1) p.o.) markedly inhibited these inflammatory reactions and CAF had a similar potency. In vitro assay demonstrated that gamma-ORZ and CAF had strong antioxidant effects comparable to those of alpha-tocopherol.

CONCLUSIONS AND IMPLICATIONS

Phytosteryl ferulates could be new potential therapeutic and/or preventive agents for gastrointestinal inflammatory diseases. Their anti-inflammatory effect could be mediated by inhibition of NF-kappaB activity, which was at least partly due to the antioxidant effect of the FA moiety in the structure of phytosteryl ferulates.