Motivated with joy or anxiety: Does approach-avoidance goal framing elicit differential reward-network activation in the brain?

Psychological research on human motivation repeatedly observed that approach goals (i.e., goals to attain success) increase task enjoyment and intrinsic motivation more strongly than avoidance goals (i.e., goals to avoid failure). The present study sought to address how the reward network in the brain-including the striatum and ventromedial prefrontal cortex-is involved when individuals engage in the same task with a focus on approach or avoidance goals. Participants reported stronger positive emotions when they focused on approach goals, but stronger anxiety and disappointment when they focused on avoidance goals. The fMRI analyses revealed that the reward network in the brain showed similar levels of activity to cues predictive of approach and avoidance goals. In contrast, the two goal states were associated with different patterns of activity in the visual cortex, hippocampus, and cerebellum during success and failure outcomes. Representation similarity analysis further revealed shared and different representations within the striatum and vmPFC between the approach and avoidance goal states, suggesting both the similarity and uniqueness of the mechanisms behind the two goal states. In addition, the distinct patterns of activation in the striatum were associated with distinct subjective experiences participants reported between the approach and the avoidance conditions. These results suggest the importance of examining the pattern of striatal activity in understanding the mechanisms behind different motivational states in humans.

Physician-scientist trainees with parenting responsibilities need financial and childcare support

Physician–scientists who become parents during their long period of training need additional funding and support for lactation, childcare and healthcare, to ensure an equitable workforce.

Tissue-Specific Dependence of Th1 Cells on the Amino Acid Transporter SLC38A1 in Inflammation

Amino acid (AA) uptake is essential for T cell metabolism and function, but how tissue sites and inflammation affect CD4+ T cell subset requirements for specific AA remains uncertain. Here we tested CD4+ T cell AA demands with in vitro and multiple in vivo CRISPR screens and identify subset- and tissue-specific dependencies on the AA transporter SLC38A1 (SNAT1). While dispensable for T cell persistence and expansion over time in vitro and in vivo lung inflammation, SLC38A1 was critical for Th1 but not Th17 cell-driven Experimental Autoimmune Encephalomyelitis (EAE) and contributed to Th1 cell-driven inflammatory bowel disease. SLC38A1 deficiency reduced mTORC1 signaling and glycolytic activity in Th1 cells, in part by reducing intracellular glutamine and disrupting hexosamine biosynthesis and redox regulation. Similarly, pharmacological inhibition of SLC38 transporters delayed EAE but did not affect lung inflammation. Subset- and tissue-specific dependencies of CD4+ T cells on AA transporters may guide selective immunotherapies.

Functional Overlap of Inborn Errors of Immunity and Metabolism Genes Define T Cell Immunometabolic Vulnerabilities

Inborn Errors of Metabolism (IEM) and Immunity (IEI) are Mendelian diseases in which complex phenotypes and patient rarity can limit clinical annotations. Few genes are assigned to both IEM and IEI, but immunometabolic demands suggest functional overlap is underestimated. We applied CRISPR screens to test IEM genes for immunologic roles and IEI genes for metabolic effects and found considerable crossover. Analysis of IEM showed N-linked glycosylation and the de novo hexosamine synthesis enzyme, Gfpt1 , are critical for T cell expansion and function. Interestingly, Gfpt1 -deficient T H 1 cells were more affected than T H 17 cells, which had increased Nagk for salvage UDP-GlcNAc synthesis. Screening IEI genes showed the transcription factor Bcl11b promotes CD4 + T cell mitochondrial activity and Mcl1 expression necessary to prevent metabolic stress. These data illustrate a high degree of functional overlap of IEM and IEI genes and point to potential immunometabolic mechanisms for a previously unappreciated set of these disorders.

HIGHLIGHTS

Inborn errors of immunity and metabolism have greater overlap than previously known Gfpt1 deficiency causes an IEM but also selectively regulates T cell subset fate Loss of Bcl11b causes a T cell deficiency IEI but also harms mitochondrial function Many IEM may have immune defects and IEI may be driven by metabolic mechanisms.

Elevated transferrin receptor impairs T cell metabolism and function in systemic lupus erythematosus

T cells in systemic lupus erythematosus (SLE) exhibit multiple metabolic abnormalities. Excess iron can impair mitochondria and may contribute to SLE. To gain insights into this potential role of iron in SLE, we performed a CRISPR screen of iron handling genes on T cells. Transferrin receptor (CD71) was identified as differentially critical for TH1 and inhibitory for induced regulatory T cells (iTregs). Activated T cells induced CD71 and iron uptake, which was exaggerated in SLE-prone T cells. Cell surface CD71 was enhanced in SLE-prone T cells by increased endosomal recycling. Blocking CD71 reduced intracellular iron and mTORC1 signaling, which inhibited TH1 and TH17 cells yet enhanced iTregs. In vivo treatment reduced kidney pathology and increased CD4 T cell production of IL-10 in SLE-prone mice. Disease severity correlated with CD71 expression on TH17 cells from patients with SLE, and blocking CD71 in vitro enhanced IL-10 secretion. T cell iron uptake via CD71 thus contributes to T cell dysfunction and can be targeted to limit SLE-associated pathology.

Acly Deficiency Enhances Myelopoiesis through Acetyl Coenzyme A and Metabolic-Epigenetic Cross-Talk

Hematopoiesis integrates cytokine signaling, metabolism, and epigenetic modifications to regulate blood cell generation. These processes are linked, as metabolites provide essential substrates for epigenetic marks. In this study, we demonstrate that ATP citrate lyase (Acly), which metabolizes citrate to generate cytosolic acetyl-CoA and is of clinical interest, can regulate chromatin accessibility to limit myeloid differentiation. Acly was tested for a role in murine hematopoiesis by small-molecule inhibition or genetic deletion in lineage-depleted, c-Kit-enriched hematopoietic stem and progenitor cells from Mus musculus. Treatments increased the abundance of cell populations that expressed the myeloid integrin CD11b and other markers of myeloid differentiation. When single-cell RNA sequencing was performed, we found that Acly inhibitor-treated hematopoietic stem and progenitor cells exhibited greater gene expression signatures for macrophages and enrichment of these populations. Similarly, the single-cell assay for transposase-accessible chromatin sequencing showed increased chromatin accessibility at genes associated with myeloid differentiation, including CD11b, CD11c, and IRF8. Mechanistically, Acly deficiency altered chromatin accessibility and expression of multiple C/EBP family transcription factors known to regulate myeloid differentiation and cell metabolism, with increased Cebpe and decreased Cebpa and Cebpb. This effect of Acly deficiency was accompanied by altered mitochondrial metabolism with decreased mitochondrial polarization but increased mitochondrial content and production of reactive oxygen species. The bias to myeloid differentiation appeared due to insufficient generation of acetyl-CoA, as exogenous acetate to support alternate compensatory pathways to produce acetyl-CoA reversed this phenotype. Acly inhibition thus can promote myelopoiesis through deprivation of acetyl-CoA and altered histone acetylome to regulate C/EBP transcription factor family activity for myeloid differentiation.

T cells specific for α-myosin drive immunotherapy-related myocarditis

Immune-related adverse events, particularly severe toxicities such as myocarditis, are major challenges to the utility of immune checkpoint inhibitors (ICIs) in anticancer therapy1. The pathogenesis of ICI-associated myocarditis (ICI-MC) is poorly understood. Pdcd1-/-Ctla4+/- mice recapitulate clinicopathological features of ICI-MC, including myocardial T cell infiltration2. Here, using single-cell RNA and T cell receptor (TCR) sequencing of cardiac immune infiltrates from Pdcd1-/-Ctla4+/- mice, we identify clonal effector CD8+ T cells as the dominant cell population. Treatment with anti-CD8-depleting, but not anti-CD4-depleting, antibodies improved the survival of Pdcd1-/-Ctla4+/- mice. Adoptive transfer of immune cells from mice with myocarditis induced fatal myocarditis in recipients, which required CD8+ T cells. The cardiac-specific protein α-myosin, which is absent from the thymus3,4, was identified as the cognate antigen source for three major histocompatibility complex class I-restricted TCRs derived from mice with fulminant myocarditis. Peripheral blood T cells from three patients with ICI-MC were expanded by α-myosin peptides. Moreover, these α-myosin-expanded T cells shared TCR clonotypes with diseased heart and skeletal muscle, which indicates that α-myosin may be a clinically important autoantigen in ICI-MC. These studies underscore the crucial role for cytotoxic CD8+ T cells, identify a candidate autoantigen in ICI-MC and yield new insights into the pathogenesis of ICI toxicity.

Prognostic impact of acute kidney injury following tricuspid transcatheter edge-to-edge repair

Background

A considerable risk of acute kidney injury (AKI) following transcatheter interventions without iodinated contrast agents has also been recognized; however, little is known about the incidence and clinical relevance of post-procedural AKI in patients undergoing transcatheter edge-to-edge repair (TEER) for tricuspid regurgitation (TR).

Purpose

This study aimed to investigate the prognostic impact and predictors of post-procedural AKI following TEER for TR.

Methods

We retrospectively analyzed 218 consecutive patients who underwent TEER for TR. Post-procedural AKI was defined as an increase in serum creatinine of ≥0.3 mg/dl within 48 hours or of ≥50% within seven days after the procedure, compared to baseline. Procedural success was defined as at least one grade reduction in TR severity upon discharge. We determined the association between post-procedural AKI and the composite outcome consisting of all-cause mortality and re-hospitalization due to heart failure within one year after the procedure.

Results

Overall, the mean age of the patients was 79±7 years, and 46.3% of the patients were male. Post-procedural AKI occurred in 32 patients (14.7%) (Figure 1). Among baseline characteristics, male sex and an estimated glomerular filtration rate of <60 ml/min/m2 were associated with the occurrence of AKI. In addition, patients without procedural success had a higher incidence of post-procedural AKI (30.4% vs. 1.8%; p=0.024).

Patients with AKI had a higher incidence of in-hospital mortality compared to those without AKI (12.5% vs. 1.1%; p=0.005). Moreover, AKI was associated with the incidence of the composite outcome within one year after TEER for TR (adjusted hazard ratio: 2.06; 95% confidence interval: 1.11–3.84; p=0.023). In addition, our restricted cubic spline curve showed that a post-procedural increase in the creatinine level within seven days after the procedure was associated with a linear trend of the risk of the composite outcome after TEER (Figure 2).

Conclusions

Post-procedural AKI occurred in 14.7% of patients undergoing TEER for TR, despite the absence of iodinated contrast agents, which was associated with worse clinical outcomes. Male sex and CKD at baseline were related to the occurrence of AKI, and the procedural success of TEER was associated with a lower incidence of AKI. Our findings highlight the clinical impact of AKI following TEER for TR and should help with identifying patients at high risk of AKI.

Funding Acknowledgement

Type of funding sources: None.

Effectiveness of transcatheter edge-to-edge repair for atrial secondary mitral regurgitation

Background

Atrial secondary mitral regurgitation (ASMR) is a subtype of SMR that is characterized by normal left ventricular (LV) function, an enlarged left atrium and mitral annulus, and flattened leaflets. This anatomical feature is different from ventricular SMR (VSMR) and might therefore impact the procedural results of transcatheter edge-to-edge repair (TEER). The effectiveness and durability of TEER in patients with ASMR has not yet been well-studied.

Purpose

This study aimed to investigate the effectiveness of TEER and anatomical characteristics related to optimal MR reduction in patients with ASMR.

Methods

We retrospectively analyzed consecutive patients who underwent MitraClip at our institution. ASMR was defined as cases that met all of the following criteria: 1) normal mitral leaflets without organic disorder, 2) LV ejection fraction >50%, and 3) absence of LV enlargement and segmental abnormality. The primary outcome measure was MR reduction to ≤1+, and its predictors were explored in a logistic regression analysis. Leaflet-to-annulus index (LAI) was measured using the mid-esophageal long-axis view in the A2-P2 segment as follows: (anterior leaflet length + posterior leaflet length) / anteroposterior length of the mitral annulus.

Results

Among 415 patients with SMR, 118 patients met the criteria for ASMR (mean age: 80±8 years; male: 39.8%) (Figure 1). Patients with ASMR had a larger mitral annulus diameter, shorter mobile posterior leaflet length, and smaller coaptation depth compared to those with VSMR.

The technical success rate was 90.7%, and the MR reduction to ≤1+ after TEER was achieved in 94 (79.7%) patients with ASMR, which was comparable with VSMR. The in-hospital mortality rate was 2.5%. In multivariable logistic analysis, a large left-atrial (LA) volume index and a low LAI were associated with a lower rate of MR reduction to ≤1+ after TEER for ASMR (odds ratio [OR]: 0.98; 95% confidence interval [CI]: 0.97–0.99, and OR per 0.1 increase: 1.98; 95% CI: 1.13–3.45, respectively). The combined assessment of the LA volume index and LAI stratified the risk of residual MR ≥2+ after TEER (Figure 2).

In addition, the use of a newer generation of the MitraClip systems (NTR/XTR or G4 systems) was associated with a higher rate of MR reduction to ≤1+ compared to older generations (OR: 4.65; 95% CI: 1.67–13.00).

Conclusions

TEER with the MitraClip system achieved a high rate of MR reduction to ≤1+ in patients with ASMR. Furthermore, the new generations of the MitraClip system may provide a more effective reduction in ASMR. Although our findings suggest that TEER with the MitraClip system is a safe and feasible approach in patients with ASMR, the combined assessment of the LA volume index and LAI might be useful to refine the device selection for transcatheter mitral valve treatment in this subgroup of SMR patients.

Funding Acknowledgement

Type of funding sources: None.

Right ventricular ejection fraction assessed by computed tomography in patients undergoing transcatheter tricuspid valve intervention

Background

The role of right-ventricular (RV) function in patients with tricuspid regurgitation (TR) undergoing transcatheter tricuspid valve interventions (TTVI) is poorly understood. Although cardiac computed tomography (CCT) provides elaborate three-dimensional (3D) visualization of the entire anatomy of the RV and theoretically allows to assess the global RV systolic function. Nevertheless, the utility of the functional assessments of the RV using CCT remains unclear in patients undergoing TTVI.

Purpose

This study investigated the association of right-ventricular ejection fraction (RVEF) assessed by CCT with clinical outcome in patients undergoing TTVI.

Methods

We retrospectively assessed 3D-RVEF by using pre-procedural CCT images in patients undergoing TTVI with either edge-to-edge repair or annuloplasty device. RV dysfunction (RVD) was defined as a CT-RVEF <45%. The primary outcome was a composite outcome, consisting of all-cause mortality and hospitalization due to heart failure, within one year after TTVI.

Results

Of 157 patients, 58 (36.9%) presented with CT-RVEF <45%. Patients with CT-RVEF <45% were more likely to be male, to have a previous history of coronary artery disease, and had higher EuroSCORE II and a lower LVEF compared to those with CT-RVEF ≥45%, while the severity of TR was comparable between the groups.

Among the patients with CT-RVEF <45%, acute procedural success was achieved in 93.1%, and in-hospital mortality was 1.7%, which were comparable to those with CT-RVEF ≥45%.

Patients with CT-RVEF <45% had an improvement in New York Heart Association functional class at follow-up compared to baseline; however, CT-RVEF <45% was associated with a higher risk of the composite outcome (adjusted hazard ratio: 3.23; 95% confidence interval: 1.52–6.88; p=0.002) (Figure 1). Furthermore, CT-RVEF had an additional value to stratify the risk of the composite outcome beyond two-dimensional transthoracic echocardiographic (TTE) assessments (Figure 2).

In addition, patients with CT-RVEF <45% exhibited an attenuated association between a reduction in TR to <3+ and a lower incidence of the composite outcome after TTVI compared to those with CT-RVEF ≥45%.

Conclusions

TTVI is safe and feasible regardless of baseline RV function, while RVD, defined as 3D-RVEF <45%, is associated with a higher risk of the composite outcomes within one year after TTVI. Furthermore, our findings suggest that the prognostic benefits of TR reduction might be attenuated in patients with RVD. Given the additional prognostic value of CT-RVEF to the conventional echocardiographic assessments, the assessments of 3D-RVEF with CCT may refine the patient selection for TTVI.

Funding Acknowledgement

Type of funding sources: None.

Refining the accuracy of right ventricular-pulmonary arterial coupling in patients undergoing transcatheter tricuspid valve treatment

Background

Assessing right-ventricular (RV) function is paramount for risk stratification but remains challenging in patients with TR. RV-pulmonary artery (PA) coupling seems more feasible for the assessment of RV function.

Methods

We assessed RV-PA coupling by the ratio of TAPSE and PASP at baseline, in which PASP was measured both by echocardiography (ePASP) and invasively using a right-heart catheter (iPASP). We also assessed the RV fractional-area change (RVFAC) as measured by transthoracic echocardiography. Participants for the present study comprised patients undergoing TTVR from June 2015 to July 2021 at the University Hospital of Bonn. Patients lacking either echocardiographic or invasive measurements for the assessment of RV-PA coupling were excluded from the analysis. The outcome was defined as a composite of mortality and rehospitalization due to heart failure within one year after the procedure.

Results

A total of 206 patients were included in the present analysis. The participants were at an advanced age (78.5±7.1 years), predominantly female (58.3%), and at a high risk for surgery (EuroSCORE II: 7.4±4.8%). Massive/torrential TR was observed in 100 of these patients. With the median follow-up duration of 201 days (interquartile range 98–424 days), the outcome occurred in 57 patients. Compared to TAPSE/ePASP, TAPSE/iPASP showed better predictability for the outcome: the AUCs were 0.582 for TAPSE/ePASP and increased to 0.714 when iPASP was applied to the formula (i.e. TAPSE/iPASP). The trend was also true for RV-PA coupling using RVFAC (AUCs: 0.561 for RVFAC/ePASP, 0.693 for RVFAC/iPASP). There was a significant correlation between ePASP and iPASP, whereas the correlation was attenuated in patients with TR beyond severe (i.e. massive/torrential TR) (interaction p = 0.01). In addition, a semiquantitative echocardiographic estimation of right atrial (RA) pressure was not correlated with the invasive measurement.

Conclusion

The present analysis confirms that RV-PA coupling, measured as TAPSE/PASP, is a powerful predictor of mortality and rehospitalization due to heart failure in patients undergoing TTVR. The predictability is even more improved if PA pressure is measured invasively and applied to the formulas.

Funding Acknowledgement

Type of funding sources: None.

Validation of expert criteria proposed by the “German Cardiac Society” for predicting procedural complexity in transcatheter edge-to-edge mitral valve repair

Background

Following up on the original EVEREST criteria and several years of procedural experience, the German Cardiac Society (GCS) proposed refined criteria indicating morphological complexity in transcatheter edge-to-edge mitral valve repair (TEER) procedures which so far have not been validated.

Methods

In a retrospective analysis of transesophageal echocardiography images of consecutive patients undergoing TEER in two high-volume centres, complexity was classified according to GCS criteria as optimal (neither characteristics of “complex” nor “very complex', see Table 1), complex (any of the “complex” criteria but no “very complex” criteria) and very complex (any of the “very complex” criteria). Associations with the procedural outcome, reintervention, survival, and heart failure rehospitalization were tested.

Results

633 patients (mean age 79 years, range 50 to 96 years, 59% male) were included, with 35% having dominant primary and 65% having dominant secondary mitral regurgitation (MR). 19% of patients were classified as having optimal, 40% as complex, and 41% as very complex morphologies. Successful clip implantation and reduction in MR ≤2 at discharge were achieved in 100% and 97% in the optimal, in 96% and 88% in the complex, and in 95% and 88% in the very complex morphologies, respectively (p for difference 0.13 and 0.42). The rate of successful clip deployment was significantly lower and the rate of reintervention significantly higher in patients with a mitral valve orifice area ≤3 cm2, compared to patients with a mitral valve orifice area >3 cm2. Pathology extent of MR likely requiring >2 clips was significantly associated with a lower rate of MR reduction to grade ≤2. Midterm (median follow-up time 640 days) mortality or hospitalization due to heart failure was significantly higher in patients with a posterior mitral leaflet length of 7–10 mm.

Conclusion

In the setting of experienced heart valve centres only a few of the complexity criteria proposed by the GCS impact on procedural and clinical outcomes. Even in the case of complex or very complex mitral valve morphology, TEER can be performed effectively with reduction of MR to ≤2 in 88% of cases.

Funding Acknowledgement

Type of funding sources: None.

MTHFD2 is a metabolic checkpoint controlling effector and regulatory T cell fate and function

Antigenic stimulation promotes T cell metabolic reprogramming to meet increased biosynthetic, bioenergetic, and signaling demands. We show that the one-carbon (1C) metabolism enzyme methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) regulates de novo purine synthesis and signaling in activated T cells to promote proliferation and inflammatory cytokine production. In pathogenic T helper-17 (Th17) cells, MTHFD2 prevented aberrant upregulation of the transcription factor FoxP3 along with inappropriate gain of suppressive capacity. MTHFD2 deficiency also promoted regulatory T (Treg) cell differentiation. Mechanistically, MTHFD2 inhibition led to depletion of purine pools, accumulation of purine biosynthetic intermediates, and decreased nutrient sensor mTORC1 signaling. MTHFD2 was also critical to regulate DNA and histone methylation in Th17 cells. Importantly, MTHFD2 deficiency reduced disease severity in multiple in vivo inflammatory disease models. MTHFD2 is thus a metabolic checkpoint to integrate purine metabolism with pathogenic effector cell signaling and is a potential therapeutic target within 1C metabolism pathways.

Six-dimensional dynamic tractography atlas of language connectivity in the developing brain

During a verbal conversation, our brain moves through a series of complex linguistic processing stages: sound decoding, semantic comprehension, retrieval of semantically coherent words, and overt production of speech outputs. Each process is thought to be supported by a network consisting of local and long-range connections bridging between major cortical areas. Both temporal and extratemporal lobe regions have functional compartments responsible for distinct language domains, including the perception and production of phonological and semantic components. This study provides quantitative evidence of how directly connected inter-lobar neocortical networks support distinct stages of linguistic processing across brain development. Novel six-dimensional tractography was used to intuitively visualize the strength and temporal dynamics of direct inter-lobar effective connectivity between cortical areas activated during each linguistic processing stage. We analysed 3401 non-epileptic intracranial electrode sites from 37 children with focal epilepsy (aged 5-20 years) who underwent extra-operative electrocorticography recording. Principal component analysis of auditory naming-related high-gamma modulations determined the relative involvement of each cortical area during each linguistic processing stage. To quantify direct effective connectivity, we delivered single-pulse electrical stimulation to 488 temporal and 1581 extratemporal lobe sites and measured the early cortico-cortical spectral responses at distant electrodes. Mixed model analyses determined the effects of naming-related high-gamma co-augmentation between connecting regions, age, and cerebral hemisphere on the strength of effective connectivity independent of epilepsy-related factors. Direct effective connectivity was strongest between extratemporal and temporal lobe site pairs, which were simultaneously activated between sentence offset and verbal response onset (i.e. response preparation period); this connectivity was approximately twice more robust than that with temporal lobe sites activated during stimulus listening or overt response. Conversely, extratemporal lobe sites activated during overt response were equally connected with temporal lobe language sites. Older age was associated with increased strength of inter-lobar effective connectivity especially between those activated during response preparation. The arcuate fasciculus supported approximately two-thirds of the direct effective connectivity pathways from temporal to extratemporal auditory language-related areas but only up to half of those in the opposite direction. The uncinate fasciculus consisted of <2% of those in the temporal-to-extratemporal direction and up to 6% of those in the opposite direction. We, for the first time, provided an atlas which quantifies and animates the strength, dynamics, and direction specificity of inter-lobar neural communications between language areas via the white matter pathways. Language-related effective connectivity may be strengthened in an age-dependent manner even after the age of 5.

Effective method of monitoring cerebral tissue oxygen saturation in cardiac surgery patients by combined use of tNIRS-1 and bispectral index

To continuously and noninvasively monitor the cerebral tissue oxygen saturation (StO₂) and hemoglobin concentration (gasHb) in cardiac surgery patients, a method combining the use of a cerebral tissue oximeter using near infrared time-resolved spectroscopy (tNIRS-1) and the bispectral index (BIS) was developed in this study. Moreover, the correlation between the estimated hemoglobin concentration (estHb), measured via tNIRS-1, and the hemoglobin concentration (gasHb), analyzed using a blood gas analyzer, were compared. The relationship between the BIS and gasHb was also examined. Through the comparison of BIS and StO₂ (r1), and estHb and gasHb (r2), the correlation between the two was clarified with maximum r1 and r2 values of 0.617 and 0.946, respectively. The relationship between BIS and gasHb (r3), showed that there was a favorable correlation with a maximum r3 value of 0.969. There was also a continuous correlation between BIS and StO₂ in patients undergoing cardiac surgery. In addition, a strong correlation was found between estHb and gasHb, and between BIS and gasHb. It was therefore concluded that the combined use of BIS and tNIRS-1 is useful to evaluate cerebral hypoxia, allowing for quick response to cerebral hypoxia and reduction of hemoglobin concentration during the operation.

805 Clonal, activated CD8+ T cells recognizing cardiac alpha-myosin drive immune checkpoint inhibitor associated myocarditis in mice

Background

Nearly half of all U.S. oncology patients meet FDA eligibility criteria to receive treatment with an immune checkpoint inhibitor (ICI). With increasing use of ICIs, preventing, diagnosing and treating immune-related adverse events (irAEs) are urgent clinical challenges. Myocarditis is an uncommon irAE, affecting < 1% of ICI-treated patients, but is highly fatal, with a mortality rate of nearly 50%. Genetically altered Pdcd1-/-Ctla4± mice die prematurely and specifically due to myocarditis. This model recapitulates the clinical and pathological features of ICI-myocarditis, including abundant cardiac infiltrating CD8+ T cells. The potential autoantigen(s) involved in ICI-myocarditis are unknown for both human disease and our murine model.

Methods

We used Pdcd1-/-Ctla4± mice on the C57BL6 background as a model of ICI-myocarditis. Single cell RNA and T cell receptor (TCR) sequencing was performed on sorted CD45+ cardiac immune cells from four affected Pdcd1-/-Ctla4± mice compared to six healthy wild type mice. The most three clonal TCRs (TCR-A, B, C), derived from two independent Pdcd1-/-Ctla4± mice, were reconstructed using stiTChR and transduced into reporter T cell lines for antigen discovery. Alpha-myosin was selected as a candidate autoantigen due to lack of presentation in the thymus. Reporter TCR-A, B, and C cells were screened using a library of overlapping 20 amino acid peptides derived from alpha-myosin in co-culture with bone marrow derived dendritic cells.

Results

Treatment with anti-CD8, but not anti-CD4, depleting antibodies rescues survival of Pdcd1-/-Ctla4± mice. Furthermore, adoptive transfer of splenocytes from Pdcd1-/-Ctla4± mice with myocarditis to Rag1-/- recipient mice was sufficient to induce fatal myocarditis. Single cell RNA/TCR sequencing on the cardiac immune infiltrate of Pdcd1-/-Ctla4± mice identified highly activated, clonal CD8+ T cells as the dominant cell population. The TCR-A cell line, the most clonal TCR identified in single cell TCR sequencing, activates NFAT, NFkB, and AP-1 reporters in response to the alpha-myosin epitope VIQYFASI. The TCR-B and TCR-C cell lines activate their reporters in response to the alpha myosin peptide DALLVIQWNIRAFMGVKNWP, indicating that alpha-myosin is an autoantigen in this mouse model of ICI-myocarditis.

Conclusions

Clonal, activated CD8+ T cells are critical for the development of ICI-myocarditis. Alpha-myosin is an autoantigen recognized by the most clonal cardiac CD8+ T cells. Efforts are currently underway to determine whether human TCRs derived from ICI-myocarditis samples recognize similar antigens. These studies are the first to identify a candidate autoantigen in ICI-myocarditis and may yield new insights into irAE pathogenesis.

Ethics Approval

All animal experiments were in accordance with the VUMC Institutional Animal Care and Use Committee (IACUC), protocol # M2000067

Impact of leaflet-to-annulus index on residual tricuspid regurgitation following transcatheter edge-to-edge tricuspid valve repair

Introduction

Edge-to-edge transcatheter tricuspid valve repair (TTVR) is a promising treatment option for tricuspid regurgitation (TR), and it is required to identify anatomical parameters to predict the procedural success of TTVR.

Purpose

In this study, we assessed leaflet-to-annulus index (LAI), a simple tool to evaluate the remodeling of tricuspid annulus in relation to the leaflets, and investigated the association of the LAI with residual TR after edge-to-edge TTVR.

Methods

Consecutive 140 patients with symptomatic TR who underwent edge-to-edge TTVR from June 2015 to July 2020 were enrolled. The LAI was calculated using preprocedural transesophageal echocardiography and was defined as follows: (anterior leaflet length + septal leaflet length)/anteroseptal tricuspid annulus diameter (Figure 1). Primary outcome was residual TR ≥3+ at discharge, and patients were allocated into two groups as follows: residual TR ≥3+ and &lt;3+. Secondary outcome was the composite outcome, consisting of all-cause mortality and heart failure hospitalization, within one year after TTVR.

Results

Of the 140 patients, 43 patients had residual TR ≥3+ after TTVR. The patients with residual TR ≥3+ had lower LAI compared to those with residual TR &lt;3+ (1.06±0.10 vs. 1.13±0.09; p=0.001). Multivariable analysis revealed that LAI was associated with residual TR ≥3+ (odds ratio [by 0.1 increase]: 0.57; 95% confidence interval [95% CI]: 0.35–0.94; p=0.02), independently of baseline TR severity, location of TR jet, and coaptation gap size (Table 1). Patients with residual TR ≥3+ had a higher incidence of the composite outcome within one year after TTVR (34.9% vs. 18.6%; log-rank p=0.04) and residual TR ≥3+ was an independent predictor of the composite outcome within one year (hazard ratio: 2.04; 95% CI: 1.01–4.11; p=0.04).

Conclusion

Lower LAI is associated with residual TR ≥3+ after edge-to-edge TTVR, which itself was a significant predictor of the one-year composite outcome. Our findings suggest that LAI is a useful tool to identify patients to be successfully treated with edge-to-edge TTVR.

Funding Acknowledgement

Type of funding sources: None. Figure 1Table 1

Risk prediction in patients with classical Low-flow, low-gradient aortic stenosis undergoing TAVI

Background

Patients with classical low-flow, low-gradient aortic stenosis (LFLG AS) undergoing transcatheter aortic valve implantation (TAVI) are known to suffer from poor prognosis. Risk prediction is difficult and predictors of outcome are scarce in this complex patient subset.

Purpose

This study aimed to develop a simple score system for risk prediction in patients with classical LFLG AS scheduled for TAVI including baseline clinical, echocardiographic and computed tomography (CT) parameters.

Methods

Among 9,150 patients undergoing TAVI (2008–2019) at five German centers, patients with classical LFLG AS were screened for availability of sufficient CT data for aortic valve calcification (AVC) quantification. Score variables were defined as all variables included into the best performing multivariable regression model. Score performance was assessed by Kaplan-Meier analysis for the endpoint of 1-year all-cause as well as c-index calculation.

Results

A total of 718 patients were included into the study. Predictors of all-cause mortality were male sex (HR 1.27 [0.98, 1.65], p=0.068), chronic obstructive pulmonary disease (HR 1.59 [1.21,2.08], p&lt;0.001), atrial fibrillation (HR 1.33 [1.03,1.70], p=0.026), stroke volume index (HR 0.96 [0.94, 0.98], p&lt;0.001), non-transfemoral access (HR 1.44 [1.09,1.91], p=0.011), pulmonary hypertension (HR 1.58 [1.20,2.08], p=0.0012) and low AVC density (HR 1.49 [1.16,1.90], p=0.0016). A score system was developed ranging from 0 points to 11 points. Kaplan-Meier analysis for low (0–2 points), moderate (3–6 points) and high score (&gt;6 points) demonstrated 1-year mortality rates of 20.9%, 28.9% and 64.3% (p&lt;0.001), respectively. C-index for prediction of 1-year mortality was 0.69 (95%-CI 0.65–0.84). The RELiEF TAVI score outperformed classical risk prediction models like the logistic euroSCORE (c-index 0.60 [95%-CI 0.51–0.72], p=0.013), the EuroSCORE II (c-index 0.57 [95%-CI 0.45–0.70], p=0.039) and the STS PROM (c-index 0.60 [0.48–0.70], p=0.035).

Conclusions

The RELiEF TAVI score is based on simple clinical, echocardiographic and CT parameters and might serve as a helpful tool for risk prediction in the vulnerable subset of patients with classical LFLG AS scheduled for TAVI.

Funding Acknowledgement

Type of funding sources: None. RELiEF TAVI Score

A guide to interrogating immunometabolism

The metabolic charts memorized in early biochemistry courses, and then later forgotten, have come back to haunt many immunologists with new recognition of the importance of these pathways. Metabolites and the activity of metabolic pathways drive energy production, macromolecule synthesis, intracellular signalling, post-translational modifications and cell survival. Immunologists who identify a metabolic phenotype in their system are often left wondering where to begin and what does it mean? Here, we provide a framework for navigating and selecting the appropriate biochemical techniques to explore immunometabolism. We offer recommendations for initial approaches to develop and test metabolic hypotheses and how to avoid common mistakes. We then discuss how to take things to the next level with metabolomic approaches, such as isotope tracing and genetic approaches. By proposing strategies and evaluating the strengths and weaknesses of different methodologies, we aim to provide insight, note important considerations and discuss ways to avoid common misconceptions. Furthermore, we highlight recent studies demonstrating the power of these metabolic approaches to uncover the role of metabolism in immunology. By following the framework in this Review, neophytes and seasoned investigators alike can venture into the emerging realm of cellular metabolism and immunity with confidence and rigour.

Cell-programmed nutrient partitioning in the tumour microenvironment

Cancer cells characteristically consume glucose through Warburg metabolism1, a process that forms the basis of tumour imaging by positron emission tomography (PET). Tumour-infiltrating immune cells also rely on glucose, and impaired immune cell metabolism in the tumour microenvironment (TME) contributes to immune evasion by tumour cells2-4. However, whether the metabolism of immune cells is dysregulated in the TME by cell-intrinsic programs or by competition with cancer cells for limited nutrients remains unclear. Here we used PET tracers to measure the access to and uptake of glucose and glutamine by specific cell subsets in the TME. Notably, myeloid cells had the greatest capacity to take up intratumoral glucose, followed by T cells and cancer cells, across a range of cancer models. By contrast, cancer cells showed the highest uptake of glutamine. This distinct nutrient partitioning was programmed in a cell-intrinsic manner through mTORC1 signalling and the expression of genes related to the metabolism of glucose and glutamine. Inhibiting glutamine uptake enhanced glucose uptake across tumour-resident cell types, showing that glutamine metabolism suppresses glucose uptake without glucose being a limiting factor in the TME. Thus, cell-intrinsic programs drive the preferential acquisition of glucose and glutamine by immune and cancer cells, respectively. Cell-selective partitioning of these nutrients could be exploited to develop therapies and imaging strategies to enhance or monitor the metabolic programs and activities of specific cell populations in the TME.

One-year outcome of transcatheter repair of tricuspid regurgitation: comparison edge-to-edge repair versus anuloplasty

 

Tricuspid regurgitation (TR) is found to be associated with increased mortality, morbidity, and impaired quality of life. The interventional tricuspid valve repair techniques are being increasingly performed. We aimed to compare the mid-term outcomes of both methods (Clipping and Banding) in our patient cohort. F

We retrospectively included 60 patients who underwent between January 2016 to March 2018 the transcatheter tricuspid valve edge-to-edge repair or annuloplasty in our center. Follow up (FU) examinations were done 12.6±7.6 months. Comprehensive transthoracic echocardiography inclusively 3D acquisitions were performed before and at FU in all patients. The 3D data were used for strain analysis of left and right ventricles and atriums through a dedicated automated offline program (TomTec).

We retrospectively included 60 patients (75±6.1 years, 40% female) with symptomatic (65% ascites, 95% edema, 100% NYHA&gt;II, 75% liver congestion) severe TR (TR&gt;II, 90% functional) at surgical high risk (EuroSCORE II: 5.2±3.2%). Forty patients underwent transcatheter TV edge-to-edge repair (TTVR, MitraClip, PASCAL), and twenty patients were treated by interventional annuloplasty (Cardioband).

At baseline, the patients underwent edge-to-edge (E2E) repair showed more comorbidities with higher EuroScore II and more decreased functional capacity. Echocardiographical, patients who underwent annuloplasty, presented a more significant coaptation gap with more impaired RV function and more dilated right atrium. In contrast, the E2E group showed to have higher right ventricular systolic pressure. Left ventricular dimensions and functions were comparable between the groups.

Left atrial volume and right atrial pressure were found to be statistically significantly reduced in both groups at FU. RV and RA fractional area change were found to be relevantly improved solely after interventional annuloplasty at FU. Left ventricular end-diastolic pressure significantly increased in the E2E group with relevant reduction of outflow/inflow ratio. Moreover, interventional annuloplasty, as expected, reduces SL diameter more significantly.

Patients showed lower symptoms and better functional capacity 12 months after interventional E2E therapy. Of note, improvement in walking distance was found to be significantly higher in patients who underwent annuloplasty. However, patients were hospitalized significantly more frequently after interventional annuloplasty.

In conclusion, both interventional techniques are safe, feasible, and effective for treatment of tricuspid regurgitation in patients at surgical high risk. Interventional annuloplasty significantly impacts on RV function and geometry, and reduces SL diameter significantly. Patients were found to have decreased symptoms, better functional capacity, as well as fewer rehospitalization 12 months after interventional E2E therapy, although they showed more comorbidities at baseline compared to interventional annuloplasty.

Funding Acknowledgement

Type of funding source: None

Risk factors and etiology of recurrent mitral regurgitation after edge-to-edge mitral valve repair

Background

Recurrent MR has been associated with poor prognosis after transcatheter mitral valve repair (TMVR) with the MitraClip system. However, little is known about risk factors and etiology of recurrent mitral regurgitation (MR) after transcatheter edge-to-edge mitral repair with the MitraClip system.

Methods

Among consecutive patients who underwent MitraClip for MR from January 2011 to March 2019, we identified 240 patients who had MR ≤2+ at discharge and follow-up echocardiography within three years after the procedure. Recurrent MR was defined as MR ≥3+ during the follow-up period. To investigate the risk factors for recurrent MR, we conducted a Cox proportional hazard model.

Results

During the follow-up period (median 491 days), 38 patients (15.8%) had recurrent MR (≥3+). The most frequent etiology of recurrent MR was degenerative (n=20, 52.6%), including single leaflet detachment (n=2, 5.3%), loss of leaflet insertion (n=11, 28.9%), and leaflet tear or prolapse (n=7, 18.4%), followed by functional MR (n=18, 47.4%). The risk factors for recurrent MR were greater LV end-diastolic volume (adjusted-HR 1.01, 95% CI 1.00–1.02, p=0.03), higher LV ejection fraction (LVEF) (adjusted-HR 1.05, 95% CI 1.01–1.08, p=0.005), and moderate MR upon discharge (adjusted-HR 2.98, 95% CI 1.50–5.95, p=0.002).After stratification according to the etiology of MR, the association of LVEF was more pronounced in patients with degenerative MR (adjusted-HR 1.07, 95% CI 1.02–1.12, p=0.003), while the association of moderate MR upon discharge was more pronounced in patients with functional MR (adjusted-HR 5.02, 95% CI 1.95–12.8, p&lt;0.001). Furthermore, patients with recurrent MR had an increased antero-posterior annulus diameter regardless of the baseline etiology of the MR.

Conclusions

Greater LV volume, higher LVEF, and moderate MR at discharge were associated with an increased risk of recurrent MR after the MitraClip procedure. A significant increase of the annulus diameter was observed regardless of the baseline etiology of the MR.

Etiology of recurrent MR

Funding Acknowledgement

Type of funding source: None

Acute response of right ventricular function following transcatheter mitral valve repair

Background

Little is known about early right ventricular (RV) response to transcatheter mitral valve repair (TMVR) and its association with clinical outcomes. We assessed the early effect of TMVR on the RV function (RVF) and sought to investigated the prognostic impact of post-procedural RV dysfunction.

Methods

From January 2011 through April 2019, consecutive patients who underwent MitraClip for severe mitral regurgitation were analyzed. We excluded patients in which the evaluation of RVF were un available. RV dysfunction was defined by an RV fractional area change (RVFAC) &lt;35% or tricuspid annular planar systolic excursion (TAPSE) &lt;16 mm. A Cox proportional regression analysis was conducted to investigate the association of post-procedural RV dysfunction with adverse outcomes (all-cause mortality and rehospitalization due to heart failure [HF]).

Results

A total of 403 patients were analyzed.Overall, the mean age was 78 years old and 59% of patients were male. The median left-ventricular ejection fraction (LVEF) was 46.1% [IQR 33.1–59.4], RVFAC was 41.9% [IQR 32.9–49.5], and TAPSE was 17 mm [IQR 14–22]. While 68 patients showed an acute improvement of RVF (35% of patients with baseline RV dysfunction), 51 patients (25% of patients with baseline normal RVF) showed an acute worsening of RVF. In patients with baseline normal RVF, atrial fibrillation (OR 4.57, 95% CI 1.56–13.40, p=0.006, HF duration &gt;18 months (OR 2.95, 95% CI 1.32–6.60, p=0.009), LVEF &lt;50% (OR 3.09, 95% CI 1.32–7.25, p=0.009), and tricuspid regurgitation≥3+ (OR 5.62, 2.28–13.90, p&lt;0.001)were associated with an increased risk of acute worsening of RVF. By contrast, in patients with baseline RV dysfunction, HF duration &gt;18 months (OR 0.43, 95% CI 0.22–0.85, p=0.01) and larger RV volume (OR 0.98, 95% CI 0.97–0.99, p&lt;0.001) were associated with less probability of acute RVF improvement. The event-free survival was significantly different according to the subgroup of variation of RVF (p=0.003). Furthermore, post-procedural RV dysfunction was associated with an increased risk of outcomes (adjusted-HR 2.38, 95% CI 1.28–4.43, p=0.006).

Conclusion

Both acute improvement and worsening of RVF can be observed after TMVR. Post-procedural RV dysfunction is an independent predictor of adverse outcomes.

Event-free survival curve

Funding Acknowledgement

Type of funding source: None

Targeted CRISPR/Cas9-based in vitro and in vivo screening of metabolic pathways in primary T cells

Chronic inflammation and immunosuppression are characterized by a dysregulation in the balance between pro-inflammatory effector T (Teff) cells and anti-inflammatory regulatory T (Treg) cells. While many currently available therapies broadly target the immune compartment, selectively targeting the specific T cell subsets that contribute to disease may provide a new avenue for development of improved immunotherapies. We have previously shown that Teff and Treg cells can be distinguished by their reliance on distinct metabolic programs, and that this exposes a way to preferentially target specific T cell subsets. We have developed in vitro and in vivo approaches to CRISPR/Cas9-based genetic screening in primary T cells to interrogate metabolic pathways. In this method, we design small-scale targeted guide RNA libraries, which are transduced into primary T cells. For the in vitro assays, these cells can be cultured under selective pressures, such as with differentiation cytokines, and sorted for populations of interest. For the in vivo assays, the transduced cells are adoptively transferred into host mice of inflammatory or cancer models, such as airway inflammation or melanoma. We have constructed and tested a library targeting the solute carrier (SLC) family of transporters, which import and export essential nutrients required to fuel the metabolic programs. Preliminary results show the glutamine transporter, SLC38a2 (SNAT2), in addition to the previously identified transporter SLC7a5 (LAT1), to be critical for primary T cell proliferative capacity. This approach provides a powerful tool for identifying critical nodes within metabolic pathways of interest in primary T cells that can potentially serve as therapeutic targets.

Dynamic tractography: Integrating cortico-cortical evoked potentials and diffusion imaging

INTRODUCTION

Cortico-cortical evoked potentials (CCEPs) are utilized to identify effective networks in the human brain. Following single-pulse electrical stimulation of cortical electrodes, evoked responses are recorded from distant cortical areas. A negative deflection (N1) which occurs 10-50 ​ms post-stimulus is considered to be a marker for direct cortico-cortical connectivity. However, with CCEPs alone it is not possible to observe the white matter pathways that conduct the signal or accurately predict N1 amplitude and latency at downstream recoding sites. Here, we develop a new approach, termed "dynamic tractography," which integrates CCEP data with diffusion-weighted imaging (DWI) data collected from the same patients. This innovative method allows greater insights into cortico-cortical networks than provided by each method alone and may improve the understanding of large-scale networks that support cognitive functions. The dynamic tractography model produces several fundamental hypotheses which we investigate: 1) DWI-based pathlength predicts N1 latency; 2) DWI-based pathlength negatively predicts N1 voltage; and 3) fractional anisotropy (FA) along the white matter path predicts N1 propagation velocity.

METHODS

Twenty-three neurosurgical patients with drug-resistant epilepsy underwent both extraoperative CCEP recordings and preoperative DWI scans. Subdural grids of 3 ​mm diameter electrodes were used for stimulation and recording, with 98-128 eligible electrodes per patient. CCEPs were elicited by trains of 1 ​Hz stimuli with an intensity of 5 ​mA and recorded at a sample rate of 1 ​kHz. N1 peak and latency were defined as the maximum of a negative deflection within 10-50 ​ms post-stimulus with a z-score > 5 relative to baseline. Electrodes and DWI were coregistered to construct electrode connectomes for white matter quantification.

RESULTS

Clinical variables (age, sex, number of anti-epileptic drugs, handedness, and stimulated hemisphere) did not correlate with the key outcome measures (N1 peak amplitude, latency, velocity, or DWI pathlength). All subjects and electrodes were therefore pooled into a group-level analysis to determine overall patterns. As hypothesized, DWI path length positively predicted N1 latency (R² ​= ​0.81, β ​= ​1.51, p ​= ​4.76e-16) and negatively predicted N1 voltage (R² ​= ​0.79, β ​= ​-0.094, p ​= ​9.30e-15), while FA predicted N1 propagation velocity (R² ​= ​0.35, β ​= ​48.0, p ​= ​0.001).

CONCLUSION

We have demonstrated that the strength and timing of the CCEP N1 is dependent on the properties of the underlying white matter network. Integrated CCEP and DWI visualization allows robust localization of intact axonal pathways which effectively interconnect eloquent cortex.

Four-dimensional map of direct effective connectivity from posterior visual areas

Lower- and higher-order visual cortices in the posterior brain, ranging from the medial- and lateral-occipital to fusiform regions, are suggested to support visual object recognition, whereas the frontal eye field (FEF) plays a role in saccadic eye movements which optimize visual processing. Previous studies using electrophysiology and functional MRI techniques have reported that tasks requiring visual object recognition elicited cortical activation sequentially in the aforementioned posterior visual regions and FEFs. The present study aims to provide unique evidence of direct effective connectivity outgoing from the posterior visual regions by measuring the early component (10-50 ​ms) of cortico-cortical spectral responses (CCSRs) elicited by weak single-pulse direct cortical electrical stimulation. We studied 22 patients who underwent extraoperative intracranial EEG recording for clinical localization of seizure foci and functionally-important brain regions. We used animations to visualize the spatiotemporal dynamics of gamma band CCSRs elicited by stimulation of three different posterior visual regions. We quantified the strength of CCSR-defined effective connectivity between the lower- and higher-order posterior visual regions as well as from the posterior visual regions to the FEFs. We found that effective connectivity within the posterior visual regions was larger in the feedforward (i.e., lower-to higher-order) direction compared to the opposite direction. Specifically, connectivity from the medial-occipital region was largest to the lateral-occipital region, whereas that from the lateral-occipital region was largest to the fusiform region. Among the posterior visual regions, connectivity to the FEF was largest from the lateral-occipital region and the mean peak latency of CCSR propagation from the lateral-occipital region to FEF was 26 ​ms. Our invasive study of the human brain using a stimulation-based intervention supports the model that the posterior visual regions have direct cortico-cortical connectivity pathways in which neural activity is transferred preferentially from the lower-to higher-order areas. The human brain has direct cortico-cortical connectivity allowing a rapid transfer of neural activity from the lateral-occipital region to the FEF.

Quantitative analysis of intracranial electrocorticography signals using the concept of statistical parametric mapping

Statistical parametric mapping (SPM) is a technique with which one can delineate brain activity statistically deviated from the normative mean, and has been commonly employed in noninvasive neuroimaging and EEG studies. Using the concept of SPM, we developed a novel technique for quantification of the statistical deviation of an intracranial electrocorticography (ECoG) measure from the nonepileptic mean. We validated this technique using data previously collected from 123 patients with drug-resistant epilepsy who underwent resective epilepsy surgery. We determined how the measurement of statistical deviation of modulation index (MI) from the non-epileptic mean (rated by z-score) improved the performance of seizure outcome classification model solely based on conventional clinical, seizure onset zone (SOZ), and neuroimaging variables. Here, MI is a summary measure quantifying the strength of in-situ coupling between high-frequency activity at >150 Hz and slow wave at 3-4 Hz. We initially generated a normative MI atlas showing the mean and standard deviation of slow-wave sleep MI of neighboring non-epileptic channels of 47 patients, whose ECoG sampling involved all four lobes. We then calculated 'MI z-score' at each electrode site. SOZ had a greater 'MI z-score' compared to non-SOZ in the remaining 76 patients. Subsequent multivariate logistic regression analysis and receiver operating characteristic analysis to the combined data of all patients revealed that the full regression model incorporating all predictor variables, including SOZ and 'MI z-score', best classified the seizure outcome with sensitivity/specificity of 0.86/0.76. The model excluding 'MI z-score' worsened its sensitivity/specificity to 0.86/0.48. Furthermore, the leave-one-out analysis successfully cross-validated the full regression model. Measurement of statistical deviation of MI from the non-epileptic mean on invasive recording is technically feasible. Our analytical technique can be used to evaluate the utility of ECoG biomarkers in epilepsy presurgical evaluation.

P4715Association of heart failure duration with clinical prognosis after transcatheter mitral valve repair

Background/Introduction

Transcatheter mitral valve repair (TMVR) in patients with heart failure (HF) and severe mitral regurgitation (MR) entails better clinical and symptomatic status. While emerging evidence indicate that HF duration is linked to adverse outcomes in patients with HF, it is not known whether the HF duration before TMVR has an effect on adverse outcomes.

Purpose

We aimed to assess the association between duration of HF before TMVR and clinical prognosis after the procedure.

Methods

We retrospectively enrolled a total of 345 patients who underwent TMVR procedure with MitraClip or Cardioband system for the treatment of symptomatic MR after guideline recommended therapy. The patients were divided into 2 groups according to the duration of HF (>18 months:, n=161, ≤18 months: shorter HF group, n=184). Cox proportional hazards analysis was performed to assess the association between duration and two-year composite endpoint (all-cause mortality, unexpected hospitalization due to HF, and repeat mitral valve therapy).

Results

Patients with longer duration of HF were more likely to be male, had greater incidence of coronary artery disease (77.0% vs. 51.6%, p<0.001), had received more frequently implantable cardioverter defibrillator or cardiac resynchronization therapy (41.0% vs. 10.3%, p<0.001), and had more decreased left ventricular ejection fraction (41.1±14.5% vs. 49.3±16.0%, p<0.001) compared to patients with shorter duration of HF. Two-year event-free survival rate was significantly lower in patients with longer duration of HF (66.3% vs. 83.8%, Log-rank p=0.01) compared to whose with shorter duration of HF. Similar trends were observed for all-cause mortality (84.8% vs. 95.9%, p=0.06) and repeat mitral valve therapy (93.4% vs. 100%, p=0.02). In the Cox proportional hazard analysis, longer duration of HF was independently associated with increased risk of adverse outcomes (Hazard ratio, 2.26; 95% confidence interval, 1.11–4.62; p=0.02) compared with shorter duration of HF.

Conclusion

Patients with the longer duration of HF before TMVR is independently associated with increased risk of adverse outcomes after the procedure. It is, however, accompanied by higher prevalence of cardiac co-morbidities in these patients. Our findings suggest that a longer duration of HF is a risk indicator and should be considered into in future clinical trials of TMVR.

Spatiotemporal dynamics of auditory and picture naming-related high-gamma modulations: A study of Japanese-speaking patients

OBJECTIVE

To characterize the spatiotemporal dynamics of auditory and picture naming-related cortical activation in Japanese-speaking patients.

METHODS

Ten patients were assigned auditory naming and picture naming tasks during extraoperative intracranial EEG recording in a tertiary epilepsy center. Time-frequency analysis determined at what electrode sites and at what time windows during each task the amplitude of high-gamma activity (65-95 Hz) was modulated.

RESULTS

The superior-temporal gyrus on each hemisphere showed high-gamma augmentation during sentence listening, whereas the left middle-temporal and inferior-frontal gyri showed high-gamma augmentation peaking around stimulus offset. Auditory naming-specific high-gamma augmentation was noted in the bilateral superior-temporal gyri as well as left frontal-parietal-temporal perisylvian network regions, whereas picture naming-specific augmentation was noted in the occipital-fusiform regions, bilaterally. The inferior pre- and postcentral gyri on each hemisphere showed modality-common high-gamma augmentation time-locked to overt responses.

CONCLUSIONS

The spatiotemporal dynamics of auditory and picture naming-related high-gamma augmentation in Japanese-speaking patients were qualitatively similar to those previously reported in studies of English-speaking patients.

SIGNIFICANCE

The cortical dynamics for auditory sentence recognition are at least partly shared by cohorts speaking two distinct languages. Multicenter studies regarding the clinical utility of high-gamma language mapping across Eastern and Western hemispheres may be feasible.

Four-dimensional functional cortical maps of visual and auditory language: Intracranial recording

OBJECTIVE

The strength of presurgical language mapping using electrocorticography (ECoG) is its outstanding signal fidelity and temporal resolution, but the weakness includes limited spatial sampling at an individual patient level. By averaging naming-related high-gamma activity at nonepileptic regions across a large number of patients, we provided the functional cortical atlases animating the neural dynamics supporting visual-object and auditory-description naming at the whole brain level.

METHODS

We studied 79 patients who underwent extraoperative ECoG recording as epilepsy presurgical evaluation, and generated time-frequency plots and animation videos delineating the dynamics of naming-related high-gamma activity at 70-110 Hz.

RESULTS

Naming task performance elicited high-gamma augmentation in domain-specific lower-order sensory areas and inferior-precentral gyri immediately after stimulus onset. High-gamma augmentation subsequently involved widespread neocortical networks with left hemisphere dominance. Left posterior temporal high-gamma augmentation at several hundred milliseconds before response onset exhibited a double dissociation; picture naming elicited high-gamma augmentation preferentially in regions medial to the inferior-temporal gyrus, whereas auditory naming elicited high-gamma augmentation more laterally. The left lateral prefrontal regions including Broca's area initially exhibited high-gamma suppression subsequently followed by high-gamma augmentation at several hundred milliseconds before response onset during both naming tasks. Early high-gamma suppression within Broca's area was more intense during picture compared to auditory naming. Subsequent lateral-prefrontal high-gamma augmentation was more intense during auditory compared to picture naming.

SIGNIFICANCE

This study revealed contrasting characteristics in the spatiotemporal dynamics of naming-related neural modulations between tasks. The dynamic atlases of visual and auditory language might be useful for planning of epilepsy surgery. Differential neural activation well explains some of the previously reported observations of domain-specific language impairments following resective epilepsy surgery. Video materials might be beneficial for the education of lay people about how the brain functions differentially during visual and auditory naming.

Distinct Regulation of Th17 and Th1 Cell Differentiation by Glutaminase-Dependent Metabolism

Activated T cells differentiate into functional subsets with distinct metabolic programs. Glutaminase (GLS) converts glutamine to glutamate to support the tricarboxylic acid cycle and redox and epigenetic reactions. Here, we identify a key role for GLS in T cell activation and specification. Though GLS deficiency diminished initial T cell activation and proliferation and impaired differentiation of Th17 cells, loss of GLS also increased Tbet to promote differentiation and effector function of CD4 Th1 and CD8 CTL cells. This was associated with altered chromatin accessibility and gene expression, including decreased PIK3IP1 in Th1 cells that sensitized to IL-2-mediated mTORC1 signaling. In vivo, GLS null T cells failed to drive Th17-inflammatory diseases, and Th1 cells had initially elevated function but exhausted over time. Transient GLS inhibition, however, led to increased Th1 and CTL T cell numbers. Glutamine metabolism thus has distinct roles to promote Th17 but constrain Th1 and CTL effector cell differentiation.

Metabolic Barriers to T Cell Function in Tumors

The metabolic programs that drive T cell functions are exquisitely sensitive to cell intrinsic and extrinsic factors, allowing T cells to respond in a fine-tuned manner to a variety of immune challenges and conditions. However, many of the factors essential for effector T cell function are perturbed in the tumor microenvironment, where oncogenic mutations drive unrestrained cancer cell growth that leads to excess nutrient consumption, excess waste excretion, and insufficient oxygen delivery. This imposes metabolic constraints on infiltrating cells that result in dysfunction and loss of potential antitumor activity in both naturally occurring as well as tailored T cells introduced as part of immunotherapy. In this review, we highlight the metabolic properties that characterize tumor-infiltrating T cells, the barriers within the metabolic landscape of the tumor microenvironment, and the opportunities and challenges they present in development of new cancer therapeutics.

Phase-amplitude coupling between interictal high-frequency activity and slow waves in epilepsy surgery

OBJECTIVE

We hypothesized that the modulation index (MI), a summary measure of the strength of phase-amplitude coupling between high-frequency activity (>150 Hz) and the phase of slow waves (3-4 Hz), would serve as a useful interictal biomarker for epilepsy presurgical evaluation.

METHODS

We investigated 123 patients who underwent focal cortical resection following extraoperative electrocorticography recording and had at least 1 year of postoperative follow-up. We examined whether consideration of MI would improve the prediction of postoperative seizure outcome. MI was measured at each intracranial electrode site during interictal slow-wave sleep. We compared the accuracy of prediction of patients achieving International League Against Epilepsy class 1 outcome between the full multivariate logistic regression model incorporating MI in addition to conventional clinical, seizure onset zone (SOZ), and neuroimaging variables, and the reduced logistic regression model incorporating all variables other than MI.

RESULTS

Ninety patients had class 1 outcome at the time of most recent follow-up (mean follow-up = 5.7 years). The full model had a noteworthy outcome predictive ability, as reflected by regression model fit R² of 0.409 and area under the curve (AUC) of receiver operating characteristic plot of 0.838. Incomplete resection of SOZ (P < 0.001), larger number of antiepileptic drugs at the time of surgery (P = 0.007), and larger MI in nonresected tissues relative to that in resected tissue (P = 0.020) were independently associated with a reduced probability of class 1 outcome. The reduced model had a lower predictive ability as reflected by R² of 0.266 and AUC of 0.767. Anatomical variability in MI existed among nonepileptic electrode sites, defined as those unaffected by magnetic resonance imaging lesion, SOZ, or interictal spike discharges. With MI adjusted for anatomical variability, the full model yielded the outcome predictive ability of R² of 0.422, AUC of 0.844, and sensitivity/specificity of 0.86/0.76.

SIGNIFICANCE

MI during interictal recording may provide useful information for the prediction of postoperative seizure outcome.

Therapeutic potential of DNA methyltransferase inhibitors with immune checkpoint inhibitor therapy in breast cancer

However, ICI therapy has thus far demonstrated limited efficacy in breast cancers, where tumor mutation rates are intermediate. Nonetheless, because of limited but positive signals in early trials, combinations of therapies to enhance anti-tumor immunity, and thus response to ICIs in breast cancer, are actively being sought. Our laboratory recently found that guadecitabine, a next-generation DNA methyltransferase inhibitor (DMTi), potentiated cytotoxic CD8⁺ T cell responses in breast cancer, which appeared to occur by the following mechanisms: (1) DMTi treatment hypomethylated and up-regulated both baseline and IFN-γ-induced MHC-I expression, thereby enhancing antigen presentation capacity, (2) DMTi treatment increased Cxcr3 ligands/chemokines (i.e., Cxcl9, Cxcl10, and Cxcl11) expression and recruited cytotoxic CD8⁺ T cells into the tumors and (3) DMTi treatment activated NFκB signaling, presumably through the expression of endogenous retroviral (ERV) sequences in tumor cells, initiating an innate response observed in other solid tumor types [Luo et al., Nat Commun 9(1):248]. Most importantly, DMTi treatment primed breast cancer and improved responses to anti-PD-L1 therapy.

Four-dimensional map of the human early visual system

OBJECTIVE

We generated a large-scale, four-dimensional map of neuronal modulations elicited by full-field flash stimulation.

METHODS

We analyzed electrocorticography (ECoG) recordings from 63 patients with focal epilepsy, and delineated the spatial-temporal dynamics of visually-elicited high-gamma_{70-110 Hz} amplitudes on a standard brain template. We then clarified the neuronal events underlying visual evoked potential (VEP) components, by correlating with high-gamma amplitude measures.

RESULTS

The medial-occipital cortex initially revealed rapid neural activation followed by prolonged suppression, reflected by augmentation of high-gamma activity lasting up to 100 ms followed by attenuation lasting up to 1000 ms, respectively. With a number of covariate factors incorporated into a prediction model, the eccentricity representation independently predicted the magnitude of post-activation suppression, which was more intense in regions representing more parafoveal visual fields compared to those of more peripheral fields. The initial negative component on VEP was sharply contoured and co-occurred with early high-gamma augmentation, whose offset then co-occurred with a large positive VEP peak. A delayed negative VEP peak was blunt and co-occurred with prolonged high-gamma attenuation.

CONCLUSIONS

Eccentricity-dependent gradient in neural suppression in the medial-occipital region may explain the functional difference between peripheral and parafoveal/central vision. Early negative and positive VEP components may reflect neural activation, whereas a delayed negative VEP peak reflecting neural suppression.

SIGNIFICANCE

Our observation provides the mechanistic rationale for transient scotoma or mild flash-blindness, characterized by physiological afterimage preferentially formed in central vision following intense but non-injurious light exposure.

Status of a compact electron cyclotron resonance ion source for National Institute of Radiological Sciences-930 cyclotron

The Kei-source is a compact electron cyclotron resonance ion source using only permanent magnets and a frequency of 10 GHz. It was developed at the National Institute of Radiological Sciences (NIRS) for producing C(4+) ions oriented for high-energy carbon therapy. It has also been used as an ion source for the NIRS-930 cyclotron. Its microwave band region for the traveling-wave-tube amplifier and maximum output power are 8-10 GHz and 350 W, respectively. Since 2006, it has provided various ion beams such as proton, deuteron, carbon, oxygen, and neon with sufficient intensity (200 μA for proton and deuteron, 50 μA for C(4+), for example) and good stability for radioisotope production, tests of radiation damage, and basic research experiments. Its horizontal and vertical emittances were measured using a screen monitor and waist-scan. The present paper reports the current status of the Kei-source.

How self-determined choice facilitates performance: a key role of the ventromedial prefrontal cortex

Recent studies have documented that self-determined choice does indeed enhance performance. However, the precise neural mechanisms underlying this effect are not well understood. We examined the neural correlates of the facilitative effects of self-determined choice using functional magnetic resonance imaging (fMRI). Participants played a game-like task involving a stopwatch with either a stopwatch they selected (self-determined-choice condition) or one they were assigned without choice (forced-choice condition). Our results showed that self-determined choice enhanced performance on the stopwatch task, despite the fact that the choices were clearly irrelevant to task difficulty. Neuroimaging results showed that failure feedback, compared with success feedback, elicited a drop in the vmPFC activation in the forced-choice condition, but not in the self-determined-choice condition, indicating that negative reward value associated with the failure feedback vanished in the self-determined-choice condition. Moreover, the vmPFC resilience to failure in the self-determined-choice condition was significantly correlated with the increased performance. Striatal responses to failure and success feedback were not modulated by the choice condition, indicating the dissociation between the vmPFC and striatal activation pattern. These findings suggest that the vmPFC plays a unique and critical role in the facilitative effects of self-determined choice on performance.

Fearful faces grab attention in the absence of late affective cortical responses

Previous studies utilizing the N2pc, an ERP correlate of attentional focusing, demonstrated that fearful faces grab attention regardless of their relevance to the current task. We tested whether this apparent automaticity was susceptible to high concurrent task demand, which is known to suppress other cortical and subcortical emotional evaluations. Our data revealed that the affective attentional capture occurred even under high task load, by which the late cortical affective activity (the LPP modulation) was entirely suppressed. We also confirmed that this effect did not occur to inverted faces and therefore required a holistic perception of facial expression. These results show that, given an intact processing of facial expression, attention is attracted by fearful faces in a relatively automatic fashion as compared to other cortical affective processes.

Decreasing adrenergic or sympathetic hyperactivity after severe traumatic brain injury using propranolol and clonidine (DASH After TBI Study): study protocol for a randomized controlled trial

Background

Severe TBI, defined as a Glasgow Coma Scale ≤ 8, increases intracranial pressure and activates the sympathetic nervous system. Sympathetic hyperactivity after TBI manifests as catecholamine excess, hypertension, abnormal heart rate variability, and agitation, and is associated with poor neuropsychological outcome. Propranolol and clonidine are centrally acting drugs that may decrease sympathetic outflow, brain edema, and agitation. However, there is no prospective randomized evidence available demonstrating the feasibility, outcome benefits, and safety for adrenergic blockade after TBI.

Methods/Design

The DASH after TBI study is an actively accruing, single-center, randomized, double-blinded, placebo-controlled, two-arm trial, where one group receives centrally acting sympatholytic drugs, propranolol (1 mg intravenously every 6 h for 7 days) and clonidine (0.1 mg per tube every 12 h for 7 days), and the other group, double placebo, within 48 h of severe TBI. The study uses a weighted adaptive minimization randomization with categories of age and Marshall head CT classification. Feasibility will be assessed by ability to provide a neuroradiology read for randomization, by treatment contamination, and by treatment compliance. The primary endpoint is reduction in plasma norepinephrine level as measured on day 8. Secondary endpoints include comprehensive plasma and urine catecholamine levels, heart rate variability, arrhythmia occurrence, infections, agitation measures using the Richmond Agitation-Sedation Scale and Agitated Behavior scale, medication use (anti-hypertensive, sedative, analgesic, and antipsychotic), coma-free days, ventilator-free days, length of stay, and mortality. Neuropsychological outcomes will be measured at hospital discharge and at 3 and 12 months. The domains tested will include global executive function, memory, processing speed, visual-spatial, and behavior. Other assessments include the Extended Glasgow Outcome Scale and Quality of Life after Brain Injury scale. Safety parameters evaluated will include cardiac complications.

Discussion

The DASH After TBI Study is the first randomized, double-blinded, placebo-controlled trial powered to determine feasibility and investigate safety and outcomes associated with adrenergic blockade in patients with severe TBI. If the study results in positive trends, this could provide pilot evidence for a larger multicenter randomized clinical trial. If there is no effect of therapy, this trial would still provide a robust prospective description of sympathetic hyperactivity after TBI.

Trial registration

ClinicalTrials.gov NCT01322048

Status of ion sources at National Institute of Radiological Sciences

The National Institute of Radiological Sciences (NIRS) maintains various ion accelerators in order to study the effects of radiation of the human body and medical uses of radiation. Two electrostatic tandem accelerators and three cyclotrons delivered by commercial companies have offered various life science tools; these include proton-induced x-ray emission analysis (PIXE), micro beam irradiation, neutron exposure, and radioisotope tracers and probes. A duoplasmatron, a multicusp ion source, a penning ion source (PIG), and an electron cyclotron resonance ion source (ECRIS) are in operation for these purposes. The Heavy-Ion Medical Accelerator in Chiba (HIMAC) is an accelerator complex for heavy-ion radiotherapy, fully developed by NIRS. HIMAC is utilized not only for daily treatment with the carbon beam but also for fundamental experiments. Several ECRISs and a PIG at HIMAC satisfy various research and clinical requirements.