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Background: Disparities exist in the representation of genders in cardiovascular clinical trials. Atrial fibrillation (AF) is associated with significant morbidity and mortality; however, understanding regarding the representation of women in AF-related clinical trials remains limited. Therefore, this systematic review sought to evaluate the representation of women in AF-related clinical trials. Methods: We conducted a systematic review of clinical trials using the PubMed, Scopus, and EMBASE databases from 1996 to January 1st, 2024, focusing on AF-related lifestyle interventions, pharmacological treatments, catheter ablation, and device therapies for AF. Data extraction and analysis encompassed trial characteristics, participant demographics, and funding sources. The primary outcome was the prevalence of female enrollees, quantified through participation-to-prevalence ratios (PPRs). This was estimated overall and stratified by funding source, intervention type, and enrollment region. Results: Of the 103 clinical trials involving 218,322 participants (39.5% female), the PPR ranged from 0.00 to 1.73, with an average PPR of 1.03. Meanwhile, 43% of the trials exhibited female under-representation (PPR, <0.8). University-funded trials showed higher female enrollment (mean PPR, 0.951) compared to industry/government-funded trials (mean PPR, 0.800). No differences were observed in the representation of women when comparing enrollment regions or intervention types. Conclusions: Despite advancements in AF management, gender disparities persist in AF-related clinical trial representation, particularly in industry/government-funded studies compared to university-funded trials. Thus, addressing implicit biases and enforcing sex equality guidelines are critical steps toward more inclusive cardiovascular research.

PURPOSE Allogeneic hematopoietic cell transplantation (HCT) improves outcomes for patients with AML harboring an internal tandem duplication mutation of FLT3 ( FLT3-ITD) AML. These patients are routinely treated with a FLT3 inhibitor after HCT, but there is limited evidence to support this. Accordingly, we conducted a randomized trial of post-HCT maintenance with the FLT3 inhibitor gilteritinib (ClinicalTrials.gov identifier: NCT02997202 ) to determine if all such patients benefit or if detection of measurable residual disease (MRD) could identify those who might benefit. METHODS Adults with FLT3-ITD AML in first remission underwent HCT and were randomly assigned to placebo or 120 mg once daily gilteritinib for 24 months after HCT. The primary end point was relapse-free survival (RFS). Secondary end points included overall survival (OS) and the effect of MRD pre- and post-HCT on RFS and OS. RESULTS Three hundred fifty-six participants were randomly assigned post-HCT to receive gilteritinib or placebo. Although RFS was higher in the gilteritinib arm, the difference was not statistically significant (hazard ratio [HR], 0.679 [95% CI, 0.459 to 1.005]; two-sided P = .0518). However, 50.5% of participants had MRD detectable pre- or post-HCT, and, in a prespecified subgroup analysis, gilteritinib was beneficial in this population (HR, 0.515 [95% CI, 0.316 to 0.838]; P = .0065). Those without detectable MRD showed no benefit (HR, 1.213 [95% CI, 0.616 to 2.387]; P = .575). CONCLUSION Although the overall improvement in RFS was not statistically significant, RFS was higher for participants with detectable FLT3-ITD MRD pre- or post-HCT who received gilteritinib treatment. To our knowledge, these data are among the first to support the effectiveness of MRD-based post-HCT therapy.

Abstract Eosinophils comprise only 1-3% of circulating leukocytes but are often a diagnostic feature associated with a variety of inflammatory and disease states, including parasitic and fungal infections, allergic diseases (e.g., asthma, rhinitis and sensitivities to specific foods), cancer, and transplant rejection. The accurate evaluations of eosinophilia as well as the release of stored eosinophil granule proteins are important for the monitoring disease progression and/or assessing the effectiveness of a given treatment strategy(ies). Despite the availability of detection methods for each of the eosinophil granule proteins logistical difficulties limiting either the assays specificity and/or sensitivity have prevented their extensive use. We have generated unique eosinophil peroxidase specific monoclonal antibodies (EPX-mAb) and a high throughput sandwich ELISA assay as a means of overcoming these difficulties. Our EPX-mAb based ELISA is ~10 times more sensitive than traditional OPD based activity assays and allows detection of EPX in mouse BAL fluid after an acute OVA protocol as well as EPX release from mouse eosinophils stimulated ex vivo. The assay is highly specific and gives no signal in samples from EPX deficient mice even with massive eosinophilia (e.g., EPX deficient IL-5 transgenic mice). More significantly, this assay detects EPX in human tissue extracts and biological fluids and thus represents novel diagnostic assay previously unavailable in clinical settings.

Abstract Chronic asthma is characterized by pulmonary remodeling and sustained lung dysfunction. The expression of IL-13 has been demonstrated as sufficient and necessary to induce these pathologies. Despite the common assumption that T cells are the primary source of IL-13 in the lung following allergen provocation, the mechanistic events leading to IL-13 expression are unclear, including the potential importance of other cells (i.e., non-T cells). Methods: Co-expression of IL-5 and eotaxin-2 induces pulmonary histopathologies and lung dysfunction that are eosinophil-dependent (i.e., they are absent in triple transgenic I5/hE2/PHIL) animals. IL-13 knockout and CD4 knockout mice were crossed with I5/hE2 mice to assess the effects of these deficiencies on the induced pathologies occurring in this double transgenic model. Conclusions: The Th2 pulmonary pathologies associated with I5/hE2 mice included recruitment of pulmonary effector T cells and increased brochoalveolar Th2 cytokine levels. Conversely, I5/hE2/CD4-/- had only a ~50% reduction in IL-13 levels as compared to I5/hE2 mice, suggesting that a significant portion of IL-13 is non-T cell derived in these mice. I5/hE2/IL-13-/- mice are improved in lung dysfunction and mucus production as compared to I5/hE2 mice. All mice had similar levels of eosinophil degranulation. These results demonstrate a role for non-T cell derived IL-13 that contributes to mucus production and lung dysfunction in a mouse model of chronic severe asthma.

Abstract Eosinophil infiltration into tumors has been associated with positive and negative growth human cancers and in mouse models of tumorigenesis. Our previous studies have shown that eosinophils infiltrate tumors and differentially accumulate in the necrotic and capsule regions of tumors. Using various eosinophil-deficient mouse models, we demonstrate that in the absence of eosinophils tumor growth is attenuated. Methods: Tumor growth kinetics were assessed using a B16F10 melanoma subcutaneous cell injection model. Eosinophil chemotaxis was assessed using an ex vivo transwell insert assay system. We compared tumor growth in wild type animals vs. various eosinophil-deficient mouse models that are transgenic line of mice (PHIL) and MBP-/-/EPO-/- double knockout mice that are deficient in eosinophil-specific proteins (major basic protein (MBP) and eosinophil peroxide (EPO)) resulting in a blockade of eosinophilpoiesis. Conclusions: The migration of eosinophils was inhibited through blocking the sphingosine-1-phosphate pathway, suggesting recruitment and accumulation is primarily an inflammatory response. Tumor growth was decreased by ~40-60% in PHIL and in MBP-/-/EPO-/- double knockout mice relative to tumors in wild type animals. In addition, EPO-/- mice, and not MBP-/-mice, replicate this ~40% reduction in tumor size implicating a significant role for EPO in tumor growth kinetics. These data suggest eosinophils respond to inflammatory mediators and mediate augment tumor growth.

Abstract Products of the 5-lipoxygenase (5-LO) pathway (i.e., cys-leukotrienes and LTB4), are contributors to lung inflammation, airway remodeling, and hyperresponsiveness associated with allergic respiratory inflammation. Eosinophils are capable of leukotriene synthesis/secretion and chemotactically respond to these compounds. However, the in vivo role of eosinophils in leukotriene mediated events during asthmatic airway inflammation is not defined. To study the link between eosinophils and leukotrienes we used the I5/E2 double transgenic mouse model of severe asthma, over-expressing IL-5 systemically and eotaxin-2 in airways, in which lung pathologies are entirely dependent on the presence of eosinophils. We show that airway levels of cysteinyl leukotrienes and LTB4 are significantly elevated in I5/E2 mice. Crosses of I5E2 mice with 5-LO knockout animals abolished AHR in the I5/E2 parental model without significant effects on lung histopathology. Administration of a cys-leukotriene receptor antagonist (Montelukast®) to I5/E2 mice replicates the effects of the total leukotriene loss in I5/E2/5-LO-/- animals. In contrast, I5/E2 mice crossed with BLT-1-/- mice which are deficient of the LTB4 receptor fail to display effects on the pulmonary pathologies occurring in the I5/E2 parental model. These data demonstrate a unique role for cys-leukotrienes in the development of AHR independent of lung remodeling events occurring in this transgenic model of severe asthma.

Abstract Atopic dermatitis and allergic contact dermatitis are two of the most common skin diseases. In both diseases, eosinophils have been suggested as potential contributors of the pathologies linked with these skin conditions. Our goal was to establish a causative relationship between the inflammatory response of chemically induced contact hypersensitivity and eosinophil-mediated activities. Wild type and eosinophil-less PHIL mice were sensitized and challenged with 2,4-dinitrochlorobenzene (DNFB) or alternatively trimellitic anhydride (TMA). Time lapsed videography was used to capture the number of itching events associated with treatment. Immunohistochemistry for eosinophils and nerves was performed to correlate the effect of dermatitis on innervation and eosinophil accumulation in these mice. Our studies showed that in both the DNFB and TMA models a robust eosinophil infiltrate occurred that was accompanied by copious levels of eosinophil degranulation. More importantly, these studies demonstrated that metrics of inflammation (e.g., induced ear swelling (i.e., thickness)) was reduced in PHIL mice relative to wild type. Our observations were also directly correlative with a loss of nerve growth and branching in PHIL mice. These data implicate eosinophils as contributors to the pathologies linked with chemically-induced contact hypersensitivity, including the induced itch responses associated with these models.

Abstract Eosinophil effector functions have been hypothesized to be mediated in part by the release of proteins stored in the secondary granules of mature cells of this leukocyte lineage. Major basic protein-1 (MBP-1) and eosinophil peroxidase (EPO) comprise the majority of protein in these granules. No role has been speculated for these proteins in eosinophilopoiesis and/or the accumulation of mature cells in circulation. Methods: Eosinophilopoiesis and eosinophil accumulation in the periphery were assessed in single and double knockout (MBP-1-/- and/or EPO-/-) mice. Bone marrow and peripheral blood leukocytes were assessed by IHC, FACS and in vitro cell culture assays. Mice were subjected to an acute OVA protocol assessing induced pulmonary pathologies in each of the strains of granule protein knockout mice. Results: We demonstrate that, unlike the single deficiency of MBP-1 or EPO, the absence of both granule proteins resulted in the loss of peripheral blood eosinophils. IHC assessments of bone marrow and spleen demonstrate that eosinophil lineage commitment occurs in these mice. However, these assessments and FACS studies demonstrated a blockade in the maturation of eosinophil-lineage committed cells. This blockade is not rescued by ex vivo culture or by bone marrow engraftment into wild type recipient mice. Similar to other eosinophil-less mouse models, MBP-1-/-/EPO-/- mice also fail to develop pulmonary inflammation in an OVA protocol.

Abstract Eosinophils and the release of cationic granule proteins have long been implicated in the development of the type 2–induced pathologies linked with respiratory inflammation. Paradoxically, the ablation of the two genes encoding the most abundant of these granule proteins, major basic protein-1 (MBP-1) and eosinophil peroxidase (EPX), results in a near collapse of eosinophilopoiesis. The specificity of this lineage ablation and the magnitude of the induced eosinopenia provide a unique opportunity to clarify the importance of eosinophils in acute and chronic inflammatory settings, as well as to identify potential mechanism(s) of action linked with pulmonary eosinophils in those settings. Specifically, we examined these issues by assessing the induced immune responses and pathologies occurring in MBP-1−/−/EPX−/− mice after 1) ovalbumin sensitization/provocation in an acute allergen-challenge protocol, and 2) crossing MBP-1−/−/EPX−/− mice with a double-transgenic model of chronic type 2 inflammation (i.e., I5/hE2). Acute allergen challenge and constitutive cytokine/chemokine expression each induced the accumulation of pulmonary eosinophils in wild-type controls that was abolished in the absence of MBP-1 and EPX (i.e., MBP-1−/−/EPX−/− mice). The expression of MBP-1 and EPX was also required for induced lung expression of IL-4/IL-13 in each setting and, in turn, the induced pulmonary remodeling events and lung dysfunction. In summary, MBP-1−/−/EPX−/− mice provide yet another definitive example of the immunoregulatory role of pulmonary eosinophils. These results highlight the utility of this unique strain of eosinophil-deficient mice as part of in vivo model studies investigating the roles of eosinophils in health and disease settings.

Abstract Rationale The release of eosinophil granule proteins in the lungs of patients with asthma has been dogmatically linked with lung remodeling and airway hyperresponsiveness. However, the demonstrated inability of established mouse models to display the eosinophil degranulation occurring in human subjects has prevented a definitive in vivo test of this hypothesis. Objectives To demonstrate in vivo causative links between induced pulmonary histopathologies/lung dysfunction and eosinophil degranulation. Methods A transgenic mouse model of chronic T-helper cell type 2–driven inflammation overexpressing IL-5 from T cells and human eotaxin 2 in the lung (I5/hE2) was used to test the hypothesis that chronic histopathologies and the development of airway hyperresponsiveness occur as a consequence of extensive eosinophil degranulation in the lung parenchyma. Measurement and Main Results Studies targeting specific inflammatory pathways in I5/hE2 mice surprisingly showed that eosinophil-dependent immunoregulative events and not the release of individual secondary granule proteins are the central contributors to T-helper cell type 2–induced pulmonary remodeling and lung dysfunction. Specifically, our studies highlighted a significant role for eosinophil-dependent IL-13 expression. In contrast, extensive degranulation leading to the release of major basic protein-1 or eosinophil peroxidase was not causatively linked to many of the induced pulmonary histopathologies. However, these studies did define a previously unappreciated link between the release of eosinophil peroxidase (but not major basic protein-1) and observed levels of induced airway mucin. Conclusions These data suggest that improvements observed in patients with asthma responding to therapeutic strategies ablating eosinophils may occur as a consequence of targeting immunoregulatory mechanisms and not by simply eliminating the destructive activities of these purportedly end-stage effector cells.