Long-term clinical outcomes of certolizumab pegol treatment in non-radiographic axial spondyloarthritis stratified by baseline MRI and CRP status.

OBJECTIVE: There is a paucity of data on long-term clinical responses in patients with non-radiographic axial spondyloarthritis (nr-axSpA) based on their baseline objective signs of inflammation such as MRI or C-reactive protein (CRP) levels. This study reports clinical outcomes up to 3 years of the C-axSpAnd trial, including safety follow-up extension (SFE) from Weeks 52 to 156, stratified by patients' baseline MRI and CRP status. METHODS: C-axSpAnd (NCT02552212) was a phase 3, multicentre study that evaluated certolizumab pegol (CZP) in patients with active nr-axSpA who had active sacroiliitis on MRI and/or elevated CRP. In this post hoc analysis, efficacy outcomes are reported to Week 156 of C-axSpAnd for patients stratified according to their MRI and CRP status at Week 0 (MRI+/CRP-, MRI-/CRP+ and MRI+/CRP+). RESULTS: Across all outcome measures, including major improvement in Ankylosing Spondylitis Disease Activity Score (ASDAS-MI) and Assessment of SpondyloArthritis international Society criteria ≥40% response (ASAS40), outcomes were generally sustained in SFE patients from Week 52 to Week 156. MRI+/CRP+ patients showed numerically higher or comparable responses relative to MRI-/CRP+ and MRI+/CRP- patients at Weeks 52 and 156; however, all three subgroups demonstrated substantial improvements from Week 0 (in CZP-randomised patients, ASDAS-MI at Week 156 [observed case]: MRI+/CRP+: 73.1%, MRI-/CRP+: 52.2%, MRI+/CRP-: 30.4%; ASAS40: MRI+/CRP+: 76.9%, MRI-/CRP+: 62.5%, MRI+/CRP-: 65.2%). CONCLUSIONS: In patients with nr-axSpA and objective signs of inflammation, long-term clinical outcomes achieved after 1 year were generally sustained at 3 years across MRI+/CRP+, MRI-/CRP+ and MRI+/CRP- subgroups.

Comparative Efficacy of Biologic Disease-Modifying Anti-Rheumatic Drugs for Non-Radiographic Axial Spondyloarthritis: A Systematic Literature Review and Bucher Indirect Comparisons.

INTRODUCTION: Biologic disease-modifying anti-rheumatic drugs (bDMARDs), including certolizumab pegol (CZP), are effective treatment options for the management of non-radiographic spondyloarthritis (nr-axSpA). In the absence of head-to-head comparisons in nr-axSpA, we conducted a systematic literature review (SLR) and indirect treatment comparison (ITC) to better understand the comparative efficacy of CZP vs. other bDMARDs. METHODS: Literature searches were conducted in October 2020 in MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials to identify randomized controlled trials in patients with nr-axSpA who had failed at least one non-steroidal anti-inflammatory drug and were treated with bDMARDs. Outcomes of interest included the Assessment of Spondyloarthritis international Society (ASAS), Ankylosing Spondylitis Disease Activity Score (ASDAS), Bath Ankylosing Spondylitis Functional Index (BASFI) and Disease Activity Index (BASDAI), and spinal pain score. Comparative efficacy was examined using a series of Bucher ITCs in subgroups matched by prior exposure to bDMARDs, disease duration, baseline C-reactive protein (CRP) levels/magnetic resonance imaging (MRI) status, and timepoints, to ensure comparability between studies. RESULTS: At 12-16 weeks, treatment with CZP was significantly more likely to achieve ASAS20/40 response and ASDAS-inactive disease status vs. etanercept (ETN), ixekizumab (IXE), and secukinumab (SEC). CZP showed statistically significant improvement in BASDAI, BASFI, and total spine pain score over adalimumab (ADA), ETN, and IXE, and in BASFI over SEC. Among patients with objective signs of inflammation (OSI; elevated CRP levels and/or inflammation on MRI at baseline), CZP had a statistically significant advantage over ETN and SEC (with or without loading dose) in achieving ASAS40, whereas the comparisons with other bDMARDs did not show any statistically significant differences. CONCLUSION: In the overall matched population, CZP performed significantly better than most comparators in improving the clinical outcomes. Among patients with OSI, CZP was found to be superior to SEC (in the MRI-/CRP + and MRI + /CRP- subgroups) and ETN (in the MRI + /CRP- subgroup) and it was comparable to golimumab and IXE across the different OSI subgroups.

Certolizumab Pegol Treatment in Patients with Axial-Spondyloarthritis-Associated Acute Anterior Uveitis: a Narrative Review.

BACKGROUND: Acute anterior uveitis (AAU) affects up to 40% of patients with axial spondyloarthritis (axSpA). An effective treatment for patients with axSpA that reduces the risk of AAU flares while also targeting axial symptoms is therefore highly desirable. Tumor necrosis factor inhibitors (TNFis) have been shown effective for treatment of axSpA and AAU occurrence, with guidelines conditionally recommending treating patients with axSpA and associated AAU with TNFi monoclonal antibodies. To date, most available data on the impact of TNFis on AAU in axSpA are from observational, open-label studies without parallel comparator arms. However, there is a growing body of evidence describing the impact of the TNFi certolizumab pegol (CZP) on the incidence of axSpA-associated AAU. OBJECTIVE: Our objective was to collate data pertaining to the impact of CZP in axSpA-associated AAU in patients across the full axSpA spectrum. METHODS: Data were obtained from four industry-supported phase 3 and 4 clinical trials (C-VIEW, C-axSpAnd, C-OPTIMISE, and RAPID-axSpA). To supplement these data, a targeted literature review was performed through searches of MEDLINE, Embase, and reference lists. RESULTS: Available data from 1467 patients from the C-VIEW, C-axSpAnd, C-OPTIMISE, and RAPID-axSpA trials show CZP to be effective in AAU in patients across the full axSpA spectrum, reducing AAU flares when compared with placebo or pretreatment period. No differences in AAU outcomes were reported when stratified by axSpA subgroup age or sex. The targeted literature review identified six further studies of CZP in spondyloarthritis-associated AAU, only one of which was specific to axSpA. CONCLUSION: CZP was effective in reducing AAU incidence in clinical trials with patients with axSpA. The targeted literature review, however, highlighted that there remains a paucity of data beyond these trials. Data from comparative studies would further enhance the body of evidence on the effects of CZP in patients with axSpA who develop AAU.

Balanced control of thermogenesis by nuclear receptor corepressors in brown adipose tissue.

Brown adipose tissue (BAT) is a key thermogenic organ whose expression of uncoupling protein 1 (UCP1) and ability to maintain body temperature in response to acute cold exposure require histone deacetylase 3 (HDAC3). HDAC3 exists in tight association with nuclear receptor corepressors (NCoRs) NCoR1 and NCoR2 (also known as silencing mediator of retinoid and thyroid receptors [SMRT]), but the functions of NCoR1/2 in BAT have not been established. Here we report that as expected, genetic loss of NCoR1/2 in BAT (NCoR1/2 BAT-dKO) leads to loss of HDAC3 activity. In addition, HDAC3 is no longer bound at its physiological genomic sites in the absence of NCoR1/2, leading to a shared deregulation of BAT lipid metabolism between NCoR1/2 BAT-dKO and HDAC3 BAT-KO mice. Despite these commonalities, loss of NCoR1/2 in BAT does not phenocopy the cold sensitivity observed in HDAC3 BAT-KO, nor does loss of either corepressor alone. Instead, BAT lacking NCoR1/2 is inflamed, particularly with respect to the interleukin-17 axis that increases thermogenic capacity by enhancing innervation. Integration of BAT RNA sequencing and chromatin immunoprecipitation sequencing data revealed that NCoR1/2 directly regulate Mmp9, which integrates extracellular matrix remodeling and inflammation. These findings reveal pleiotropic functions of the NCoR/HDAC3 corepressor complex in BAT, such that HDAC3-independent suppression of BAT inflammation counterbalances stimulation of HDAC3 activity in the control of thermogenesis.

Certolizumab Pegol Efficacy in Patients With Non-Radiographic Axial Spondyloarthritis Stratified by Baseline MRI and C-Reactive Protein Status: An Analysis From the C-axSpAnd Study.

OBJECTIVE: Tumor necrosis factor inhibitors (TNFi) are an effective treatment for non-radiographic axial spondyloarthritis (nr-axSpA). To be eligible, however, many authorities require patients with nr-axSpA to show active sacroiliitis on magnetic resonance imaging (MRI) and/or an elevated C-reactive protein (CRP) level, possibly resulting in a perception that patients with nr-axSpA without both factors have only low responses to TNFi treatment. We evaluated clinical responses to certolizumab pegol (CZP) in patients with nr-axSpA stratified by baseline MRI/CRP status. METHODS: C-axSpAnd was a phase 3, multicenter study on CZP in adult patients with active nr-axSpA and objective signs of inflammation. This analysis assessed efficacy of CZP over the 52-week randomized, double-blind, placebo-controlled period in patients stratified into subgroups based on the presence of active sacroiliitis on MRI and CRP level at baseline. RESULTS: CZP-treated patients across all MRI/CRP subgroups achieved clinical responses greater than placebo. Across outcome measures, CZP-treated MRI+/CRP+ patients demonstrated the greatest clinical responses, but substantial improvements were also observed in CZP-treated MRI+/CRP- and MRI-/CRP+ patients. Ankylosing Spondylitis Disease Activity Score Major Improvement response rates at week 52 among CZP-treated patients (75.6% MRI+/CRP+; 47.5% MRI-/CRP+; and 29.7% MRI+/CRP-) were higher than rates in placebo groups (range: 3.9%-12.5%). Assessment of SpondyloArthritis international Society 40% response, Bath Ankylosing Spondylitis Disease Activity Index, and Bath Ankylosing Spondyloarthritis Functional Index had similar response patterns, although differences between the CZP-treated MRI/CRP subgroups were smaller. Clinical responses among CZP-treated patients were also observed in additional subgroups, including those with low Spondyloarthritis Research Consortium of Canada MRI sacroiliac joint inflammation scores and those with normal baseline CRP levels. CONCLUSION: Our findings indicate that CZP treatment benefits patients with nr-axSpA across MRI+/CRP+, MRI-/CRP+, and MRI+/CRP- subgroups.

Stressors and Information-Seeking by Dialysis and Transplant Patients During COVID-19, Reported on a Telephone Hotline: A Mixed-Methods Study.

Rationale & Objective: In early 2020, we activated a telephone hotline, the coronavirus disease 2019 (COVID-19) Kidney or Transplant Listening and Resource Center, to learn more about the impact of the COVID-19 pandemic on the stress and information-seeking behaviors of dialysis and transplant patients. Study Design: A mixed-methods study including semi-structured, qualitative interviews probing about emotional, health, and financial challenges experienced and quantitative surveys assessing depression and anxiety levels and information-seeking behaviors. Setting & Participants: 99 participants (28 dialysis patients; 71 transplant patients), varying by race and ethnicity (Hispanic, 25.3%; White, 23.2%; Asian, 24.2%; Black, 24.2%), shared their COVID-19 pandemic experiences and information-seeking behaviors by telephone. Interviews and surveys were conducted from June 17, 2020, to November 24, 2020. Analytical Approach: Qualitative themes were identified using thematic analysis. Frequencies were calculated to assess levels of depression and anxiety using the Patient Health Questionnaire for Depression and Anxiety and types of information-seeking behaviors. Results: 7 themes and 16 subthemes emerged. Themes of commonly reported stressors include postponing medical visits; decreased accessibility of getting medication; difficulty in receiving up-to-date, patient-focused health information and dialysis supplies; and delays in medical appointments. Other stressors include losses of health insurance and income, and increased vigilance in behaviors to avoid contracting COVID-19. 15 participants had moderate to severe anxiety and depression symptoms and reported more frequent and severe panic attacks after the COVID-19 pandemic. Participants sought emotional support from family, friends, and faith communities. They also commonly obtained information from news media and reported needing more transplant-specific updates about COVID-19, and frequent communication from their kidney and transplant specialists. Limitations: This convenience sample of individuals willing to share their experiences through a telephone hotline may not generalize to all dialysis and transplant patients; stressors related to the COVID-19 pandemic for these patients continue to change. Conclusions: As the impact of the pandemic continues, needs-based interventions tailored for the kidney and transplant community, including access to mental health resources, education, and support for care transitions, should continue.

Long-term safety and clinical outcomes of certolizumab pegol treatment in patients with active non-radiographic axial spondyloarthritis: 3-year results from the phase 3 C-axSpAnd study.

BACKGROUND: 52-week results from C-axSpAnd demonstrated the safety and efficacy of certolizumab pegol (CZP) in patients with active non-radiographic axial spondyloarthritis (nr-axSpA) and objective signs of inflammation (sacroiliitis on MRI and/or elevated C-reactive protein levels). Long-term safety and clinical outcomes, including MRI assessments, are evaluated up to 3 years for CZP-treated patients with nr-axSpA. METHODS: C-axSpAnd was a phase 3 study comprising a 1-year double-blind, placebo-controlled period and 2-year open-label safety follow-up extension (SFE). At baseline, 317 patients were randomised 1:1 to placebo or CZP 200 mg every 2 weeks. Patients completing the double-blind phase who enrolled into the SFE received open-label CZP for an additional 104 weeks. Long-term safety and clinical outcomes are reported to Week 156. Continuous outcomes are presented as observed case (OC) and dichotomous outcomes as OC and with non-responder imputation. RESULTS: 243/317 (76.7%) patients entered the SFE, during which 149 (61.3%) experienced ≥1 treatment-emergent adverse event (TEAE); 15 (3.3/100 patient-years) experienced serious TEAEs. Continuous outcome scores (including Ankylosing Spondylitis Disease Activity Score [ASDAS]: 1.8; Bath Ankylosing Spondylitis Disease Activity Index [BASDAI]: 2.7) at Week 52 were maintained at Week 156 (ASDAS: 1.8; BASDAI: 2.6) for the initial CZP-randomised group. Mean SPARCC MRI sacroiliac joint inflammation scores for these patients decreased at Week 52 (baseline: 7.6; Week 52: 1.7), remaining low at Week 156 (2.4). CONCLUSIONS: CZP treatment was well tolerated up to 3 years, with no new safety signals versus previous reports. Clinical outcomes achieved after 1 year were sustained to 3 years. TRIAL REGISTRATION NUMBER: NCT02552212.

Isoform-specific functions of PPARγ in gene regulation and metabolism.

Peroxisome proliferator-activated receptor γ (PPARγ) is a nuclear receptor that is a vital regulator of adipogenesis, insulin sensitivity, and lipid metabolism. Activation of PPARγ by antidiabetic thiazolidinediones (TZD) reverses insulin resistance but also leads to weight gain that limits the use of these drugs. There are two main PPARγ isoforms, but the specific functions of each are not established. Here we generated mouse lines in which endogenous PPARγ1 and PPARγ2 were epitope-tagged to interrogate isoform-specific genomic binding, and mice deficient in either PPARγ1 or PPARγ2 to assess isoform-specific gene regulation. Strikingly, although PPARγ1 and PPARγ2 contain identical DNA binding domains, we uncovered isoform-specific genomic binding sites in addition to shared sites. Moreover, PPARγ1 and PPARγ2 regulated a different set of genes in adipose tissue depots, suggesting distinct roles in adipocyte biology. Indeed, mice with selective deficiency of PPARγ1 maintained body temperature better than wild-type or PPARγ2-deficient mice. Most remarkably, although TZD treatment improved glucose tolerance in mice lacking either PPARγ1 or PPARγ2, the PPARγ1-deficient mice were protected from TZD-induced body weight gain compared with PPARγ2-deficient mice. Thus, PPARγ isoforms have specific and separable metabolic functions that may be targeted to improve therapy for insulin resistance and diabetes.

The Importance of Monitoring the Postpartum Period in Moderate to Severe Crohn's Disease.

BACKGROUND: Prior research demonstrates Crohn's disease patients often do well in pregnancy; however, less is known about the risk of flare in the postpartum period. METHODS: A retrospective chart review was conducted at a tertiary care inflammatory bowel disease center. All pregnant women with Crohn's disease who were followed in the postpartum period, defined as 6 months after delivery, were included. Statistical analysis included χ 2 analysis, Wilcoxon rank sum test, and logistic regression analysis. The primary outcome of interest was rate of flare in the postpartum period. RESULTS: There were 105 patients included in the study, with a majority (68%) on biologic medication during pregnancy. Thirty-one patients (30%) had a postpartum flare at a median of 9 weeks (range 2-24 weeks). Twenty-five patients (81%) had their postpartum flare managed in the outpatient setting with medications (only 4 of these patients required prednisone). 6 of 31 patients (19%) were hospitalized at a median of 4 weeks (range 2-26 weeks) after delivery, requiring intravenous corticosteroids or surgery. In multivariable regression, there was no significant increase in risk of postpartum flare with increasing maternal age, flare during pregnancy, or steroid or biologic use during pregnancy. Smoking during pregnancy increased risk of postpartum flare (odds ratio, 16.2 [1.72-152.94], P < 0.05). CONCLUSION: In a cohort of Crohn's disease patients, 30% experienced a postpartum flare despite being on medical therapy, but most were able to be managed in the outpatient setting.

Neuropilin 1 regulates bone marrow vascular regeneration and hematopoietic reconstitution.

Ionizing radiation and chemotherapy deplete hematopoietic stem cells and damage the vascular niche wherein hematopoietic stem cells reside. Hematopoietic stem cell regeneration requires signaling from an intact bone marrow (BM) vascular niche, but the mechanisms that control BM vascular niche regeneration are poorly understood. We report that BM vascular endothelial cells secrete semaphorin 3 A (SEMA3A) in response to myeloablation and SEMA3A induces p53 - mediated apoptosis in BM endothelial cells via signaling through its receptor, Neuropilin 1 (NRP1), and activation of cyclin dependent kinase 5. Endothelial cell - specific deletion of Nrp1 or Sema3a or administration of anti-NRP1 antibody suppresses BM endothelial cell apoptosis, accelerates BM vascular regeneration and concordantly drives hematopoietic reconstitution in irradiated mice. In response to NRP1 inhibition, BM endothelial cells increase expression and secretion of the Wnt signal amplifying protein, R spondin 2. Systemic administration of anti - R spondin 2 blocks HSC regeneration and hematopoietic reconstitution which otherwise occurrs in response to NRP1 inhibition. SEMA3A - NRP1 signaling promotes BM vascular regression following myelosuppression and therapeutic blockade of SEMA3A - NRP1 signaling in BM endothelial cells accelerates vascular and hematopoietic regeneration in vivo.

Individual-specific functional epigenomics reveals genetic determinants of adverse metabolic effects of glucocorticoids.

Glucocorticoids (GCs) are widely used as anti-inflammatory drugs, but their long-term use has severe metabolic side effects. Here, by treating multiple individual adipose stem cell-derived adipocytes and induced pluripotent stem cell-derived hepatocytes with the potent GC dexamethasone (Dex), we uncovered cell-type-specific and individual-specific GC-dependent transcriptomes and glucocorticoid receptor (GR) cistromes. Individual-specific GR binding could be traced to single-nucleotide polymorphisms (SNPs) that altered the binding motifs of GR or its cooperating factors. We also discovered another set of genetic variants that modulated Dex response through affecting chromatin accessibility or chromatin architecture. Several SNPs that altered Dex-regulated GR binding and gene expression controlled Dex-driven metabolic perturbations. Remarkably, these genetic variations were highly associated with increases in serum glucose, lipids, and body mass in subjects on GC therapy. Knowledge of the genetic variants that predispose individuals to metabolic side effects allows for a precision medicine approach to the use of clinically relevant GCs.

Nuclear receptors and transcriptional regulation in non-alcoholic fatty liver disease.

BACKGROUND: As a result of a sedentary lifestyle and excess food consumption in modern society, non-alcoholic fatty liver disease (NAFLD) characterized by fat accumulation in the liver is becoming a major disease burden. Non-alcoholic steatohepatitis (NASH) is an advanced form of NAFLD characterized by inflammation and fibrosis that can lead to hepatocellular carcinoma and liver failure. Nuclear receptors (NRs) are a family of ligand-regulated transcription factors that closely control multiple aspects of metabolism. Their transcriptional activity is modulated by various ligands, including hormones and lipids. NRs serve as potential pharmacological targets for NAFLD/NASH and other metabolic diseases. SCOPE OF REVIEW: In this review, we provide a comprehensive overview of NRs that have been studied in the context of NAFLD/NASH with a focus on their transcriptional regulation, function in preclinical models, and studies of their clinical utility. MAJOR CONCLUSIONS: The transcriptional regulation of NRs is context-dependent. During the dynamic progression of NAFLD/NASH, NRs play diverse roles in multiple organs and different cell types in the liver, which highlights the necessity of targeting NRs in a stage-specific and cell-type-specific manner to enhance the efficacy and safety of treatment methods.

Chronic myeloid leukemia stem cells require cell-autonomous pleiotrophin signaling.

Tyrosine kinase inhibitors (TKIs) induce molecular remission in the majority of patients with chronic myelogenous leukemia (CML), but the persistence of CML stem cells hinders cure and necessitates indefinite TKI therapy. We report that CML stem cells upregulate the expression of pleiotrophin (PTN) and require cell-autonomous PTN signaling for CML pathogenesis in BCR/ABL+ mice. Constitutive PTN deletion substantially reduced the numbers of CML stem cells capable of initiating CML in vivo. Hematopoietic cell-specific deletion of PTN suppressed CML development in BCR/ABL+ mice, suggesting that cell-autonomous PTN signaling was necessary for CML disease evolution. Mechanistically, PTN promoted CML stem cell survival and TKI resistance via induction of Jun and the unfolded protein response. Human CML cells were also dependent on cell-autonomous PTN signaling, and anti-PTN antibody suppressed human CML colony formation and CML repopulation in vivo. Our results suggest that targeted inhibition of PTN has therapeutic potential to eradicate CML stem cells.

Dickkopf-1 Treatment Stimulates Hematopoietic Regenerative Function in Infused Endothelial Progenitor Cells.

Acute high-dose radiation injury damages the bone marrow hematopoietic stem and progenitor cell compartment. This damage compromises the functional ability of the bone marrow to produce mature blood cells and results in an increased risk of death due to hematopoietic complications. Past work has shown that the bone marrow endothelium provides critical cues, which promote hematopoietic stem cell regeneration after injury. Additionally, transfusion of endothelial cells after radiation injury has been shown to promote recovery of both the bone marrow vasculature and hematopoietic systems. In this work, we examined the regenerative capacity of intravenous infusion of umbilical cord-blood derived endothelial progenitor cells (EPCs) since this is a cell source which is easy to obtain, expand and cryopreserve. We show that pre-treatment with the Wnt-antagonist Dickkopf1 (Dkk1) augments EPC regenerative function in an allogeneic mouse transplant model. Here, hematopoietic recovery was assessed in Balb/c mice after 5 Gy total-body irradiation and transplantation with C57/BL6-derived EPCs either with or without Dkk1 pre-treatment. The Dkk1-treated EPC group had significantly faster recovery of peripheral white blood cells, total bone marrow cellularity, bone marrow progenitors and BM endothelial cells compared to EPC treatment alone or saline controls. Importantly, after an LD50/30 dose of 8 Gy in the Balb/c mouse, Dkk1-treated EPCs were able to rescue 100% of irradiated mice versus 80% in the EPC control group and only 33% in the saline-treated group. To understand how Dkk1 induces regenerative function in the EPCs, we screened for pro-regenerative factors secreted by the EPC in response to Dkk1. Dkk1-treated EPCs were observed to secrete high levels of the anti-fibrotic protein follistatin as well as several proteins known to promote regeneration including EGF, VEGF and G-CSF. This work demonstrates the potential for Dkk1-treated EPCs as a rescue therapeutic for victims of acute radiation injury.

Emotional Underarousal and Overarousal and Engagement in Relational Aggression: Interactions between Relational Victimization, Physiological Reactivity, and Emotional Sensitivity.

The present study examined if overarousal (i.e., dysregulation and high emotional sensitivity) and underarousal (i.e., fearlessness and emotional insensitivity) to peer stress, reflected in physiological reactivity and subjective emotional sensitivity, exacerbated risk for relational aggression in relationally victimized children. Participants were a community sample of 125 children (10-12 years, M = 11.34 years, SD = 0.89; 45% female). Teachers provided ratings of children's relational victimization and relational aggression. Children's physiological reactivity was assessed based on skin conductance level (SCL) reactivity and respiratory sinus arrhythmia (RSA) reactivity to a standardized peer rejection task. Children's subjective emotional sensitivity was assessed using self-reported ratings of distress to hypothetical relational provocation vignettes. Results indicated that relational victimization was significantly associated with relational aggression only for children with high SCL reactivity and high emotional sensitivity (i.e., physiological and subjective overarousal) and for children with low SCL reactivity and low emotional sensitivity (i.e., physiological and subjective underarousal); relational victimization did not predict relational aggression among children with high SCL reactivity but low emotional sensitivity or among children with low SCL reactivity but high emotional sensitivity. Relational victimization was also marginally more strongly associated with relational aggression for children displaying RSA augmentation. Results suggest emotional overarousal and underarousal may both serve as vulnerabilities for relational aggression among relationally victimized youth, and underscore the importance of including physiological and subjective indices of emotional reactivity in studies of aggression. Implications for theory and intervention are discussed.