Eosinophils in wound healing and epithelial remodeling: Is coagulation a missing link?

Membrane damage by MBP-1 is mediated by pore formation and amplified by mtDNA

Eosinophils play a crucial role in host defense while also contributing to immunopathology through the release of inflammatory mediators. Characterized by distinctive cytoplasmic granules, eosinophils securely store and rapidly release various proteins exhibiting high toxicity upon extracellular release. Among these, major basic protein 1 (MBP-1) emerges as an important mediator in eosinophil function against pathogens and in eosinophil-associated diseases. While MBP-1 targets both microorganisms and host cells, its precise mechanism remains elusive. We demonstrate that formation of small pores by MBP-1 in lipid bilayers induces membrane permeabilization and disrupts potassium balance. Additionally, we reveal that mitochondrial DNA (mtDNA) present in eosinophil extracellular traps (EETs) amplifies MBP-1 toxic effects, underscoring the pivotal role of mtDNA in EETs. Furthermore, we present evidence indicating that absence of CpG methylation in mtDNA contributes to the regulation of MBP-1-mediated toxicity. Taken together, our data suggest that the mtDNA scaffold within extracellular traps promotes MBP-1 toxicity.

Mind bomb 2 limits inflammatory dermatitis in Sharpin mutant mice independently of cell death

Skin inflammation is a complex process implicated in various dermatological disorders. The chronic proliferative dermatitis (cpd) phenotype driven by the cpd mutation (cpdm) in the Sharpin gene is characterized by dermal inflammation and epidermal abnormalities. Tumour necrosis factor (TNF) and caspase-8-driven cell death causes the pathogenesis of Sharpincpdm mice; however, the role of mind bomb 2 (MIB2), a pro-survival E3 ubiquitin ligase involved in TNF signaling, in skin inflammation remains unknown. Here, we demonstrate that MIB2 antagonizes inflammatory dermatitis in the context of the cpd mutation. Surprisingly, the role of MIB2 in limiting skin inflammation is independent of its known pro-survival function and E3 ligase activity. Instead, MIB2 enhances the production of wound-healing molecules, granulocyte colony-stimulating factor, and Eotaxin, within the skin. This discovery advances our comprehension of inflammatory cytokines and chemokines associated with cpdm pathogenesis and highlights the significance of MIB2 in inflammatory skin disease that is independent of its ability to regulate TNF-induced cell death.

The Impact of Blood Morphological Parameters on Treatment Outcomes in Tennis Elbow Patients Receiving Platelet-Rich Plasma (PRP) Therapy: A Prospective Study

Platelet-rich plasma (PRP) therapy holds substantial promise for the treatment of tennis elbow, a complex and challenging musculoskeletal condition. The aim of the study was to assess whether there are correlations between the levels of individual morphotic elements determined in whole blood and the outcomes of tennis elbow treatment with PRP injection, as measured using patient-reported outcome measures (PROMs) such as the Visual Analog Scale (VAS), Quick Disabilities of the Arm, Shoulder, and Hand (QDASH), and Patient-Rated Tennis Elbow Evaluation (PRTEE). A prospective analysis was conducted on 107 patients (132 elbows) undergoing lateral epicondylitis treatment with (PRP) injections. Patients completed VAS, PRTEE, and QDASH questionnaires on the day of PRP administration and at established checkpoints (2, 4, 8, 12, 24, 52, and 104 weeks). Minimal clinically important difference (MCID) was employed to assess the treatment effects. Then, correlations were measured within each PROM, and the impact of the concentration of individual blood parameters on the MCID outcomes was assessed. Analyzing the relationships between the MCID+ and MCID- groups, significant correlations for the VAS and QDASH scales were observed. The level of individual morphotic elements in the blood may have influenced the treatment outcome, as measured using specific patient-reported outcome measures (PROMs). Regarding the VAS scale, factors favoring a positive treatment outcome included higher values of eosinophils (EOS) and basophils (BASO). For the QDASH scale, these factors were a lower value of mean corpuscular volume (MCV) and a higher mean corpuscular hemoglobin (MCH). The levels of certain blood parameters, such as EOS and BASO, in the current study influenced the classification of patients into MCID+ or MCID- groups, based on the VAS and QDASH scales.

Hypereosinophilia causes progressive cardiac pathologies in mice

Hypereosinophilic syndrome is a progressive disease with extensive eosinophilia that results in organ damage. Cardiac pathologies are the main reason for its high mortality rate. A better understanding of the mechanisms of eosinophil-mediated tissue damage would benefit therapeutic development. Here, we describe the cardiac pathologies that developed in a mouse model of hypereosinophilic syndrome. These IL-5 transgenic mice exhibited decreased left ventricular function at a young age which worsened with age. Mechanistically, we demonstrated infiltration of activated eosinophils into the heart tissue that led to an inflammatory environment. Gene expression signatures showed tissue damage as well as repair and remodeling processes. Cardiomyocytes from IL-5Tg mice exhibited significantly reduced contractility relative to wild type (WT) controls. This impairment may result from the inflammatory stress experienced by the cardiomyocytes and suggest that dysregulation of contractility and Ca2+ reuptake in cardiomyocytes contributes to cardiac dysfunction at the whole organ level in hypereosinophilic mice.

Eosinophils and tissue remodeling: Relevance to airway disease

The ability of human tissue to reorganize and restore its existing structure underlies tissue homeostasis in the healthy airways, but in disease can persist without normal resolution, leading to an altered airway structure. Eosinophils play a cardinal role in airway remodeling both in health and disease, driving epithelial homeostasis and extracellular matrix turnover. Physiological consequences associated with eosinophil-driven remodeling include impaired lung function and reduced bronchodilator reversibility in asthma, and obstructed airflow in chronic rhinosinusitis with nasal polyps. Given the contribution of airway remodeling to the development and persistence of symptoms in airways disease, targeting remodeling is an important therapeutic consideration. Indeed, there is early evidence that eosinophil attenuation may reduce remodeling and disease progression in asthma. This review provides an overview of tissue remodeling in both health and airway disease with a particular focus on eosinophilic asthma and chronic rhinosinusitis with nasal polyps, as well as the role of eosinophils in these processes and the implications for therapeutic interventions. Areas for future research are also noted, to help improve our understanding of the homeostatic and pathological roles of eosinophils in tissue remodeling, which should aid the development of targeted and effective treatments for eosinophilic diseases of the airways.

Preoperative elevated eosinophils in peripheral blood for prediction of postoperative recurrence of chronic subdural hematoma

OBJECTIVE

Chronic subdural hematoma (CSDH) is a common neurological disease with a significant postoperative recurrence rate. There are numerous reported studies of the development of CSDH. In recent years, fibrinolysis, angiogenesis, and inflammation have all been identified as relevant factors in the development of CSDH. While several authors have reported risk factors associated with CSDH recurrence, differential blood count of leukocytes has not yet been discussed. Therefore, in this study the authors aimed to retrospectively investigate the association between differential blood leukocyte count and the rate of CSDH recurrence.

METHODS

The authors retrospectively reviewed 476 patients with 529 CSDHs who underwent surgery at a single institution between January 2011 and December 2021. After exclusion of patients who had not undergone a differential blood test of leukocytes preoperatively, CSDHs in 517 cerebral hemispheres of 466 patients were included in the study. Peripheral blood eosinophil counts ≥ 100/µL were considered eosinophil rich.

RESULTS

CSDHs in 494 cerebral hemispheres of 445 patients were followed up postoperatively for at least 3 months or until resolution indicated by CSDH disappearance. Postoperative recurrence of CSDH was observed in 46 cerebral hemispheres (9.3%). Among the preoperative differential blood counts of all leukocytes, eosinophils alone were significantly associated with CSDH recurrence (median [IQR] 76/µL [30-155/µL] vs 119/µL [39-217/µL]; p = 0.03). Multivariable regression analysis showed thrombocytopenia (adjusted OR [aOR] 5.23, 95% CI 1.85-14.79; p = 0.002), use of anticoagulant drugs (aOR 2.51, 95% CI 1.17-5.38; p = 0.02), hematoma volume (10 mL per increase) (aOR 1.08, 95% CI 1.00-1.16; p = 0.04), and eosinophil-rich peripheral blood (aOR 2.22, 95% CI 1.17-4.23; p = 0.02) were all independent predictors for CSDH recurrence.

CONCLUSIONS

This study showed that preoperative peripheral blood eosinophil count was an independent risk factor for CSDH recurrence. Therefore, patients with CSDH who have elevated eosinophils preoperatively in peripheral blood require careful follow-up.

Eosinophils in the tumor microenvironment: implications for cancer immunotherapy

Despite being an integral part of the immune response in the tumor microenvironment (TME), few studies have mechanistically elucidated eosinophil functions in cancer outcomes. Eosinophils are a minor population of granulocytes that are mostly explored in asthma and allergic disorders. Their influence on primary and metastatic tumors, however, has recently come to light. Eosinophils' diverse armamentarium of mediators and receptors allows them to participate in innate and adaptive immunity, such as type 1 and type 2 immunity, and shape TME and tumor outcomes. Based on TME cells and cytokines, activated eosinophils drive other immune cells to ultimately promote or suppress tumor growth. Discovering exactly what conditions determine the pro-tumorigenic or anti-tumorigenic role of eosinophils allows us to take advantage of these signals and devise novel strategies to target cancer cells. Here, we first revisit eosinophil biology and differentiation as recognizing eosinophil mediators is crucial to their function in homeostatic and pathological conditions as well as tumor outcome. The bulk of our paper discusses eosinophil interactions with tumor cells, immune cells-including T cells, plasma cells, natural killer (NK) cells-and gut microbiota. Eosinophil mediators, such as IL-5, IL-33, granulocyte-macrophage colony-stimulating factor (GM-CSF), thymic stromal lymphopoietin (TSLP), and CCL11 also determine eosinophil behavior toward tumor cells. We then examine the implications of these findings for cancer immunotherapy approaches, including immune checkpoint blockade (ICB) therapy using immune checkpoint inhibitors (ICIs) and chimeric antigen receptor (CAR) T cell therapy. Eosinophils synergize with CAR T cells and ICB therapy to augment immunotherapies.

Effect of Benralizumab on Mucus Plugs in Severe Eosinophilic Asthma

INTRODUCTION

Mucus plugs are associated with airway obstruction in severe asthma and are involved in the formation of activated eosinophils. Benralizumab, an anti-interleukin-5 receptor antibody, markedly reduces not only peripheral blood eosinophils but also airway eosinophils; however, its effects on mucus plugs have not been clarified. In this study, we examined the efficacy of benralizumab on mucus plugs using computed tomography (CT) imaging.

METHODS

Twelve patients who were administered benralizumab and underwent CT before and approximately 4 months after the introduction of benralizumab were included in this study, and the number of mucus plugs before and after benralizumab administration was compared. The correlation between the clinical background and treatment effect was also examined.

RESULTS

The number of mucus plugs significantly decreased after the introduction of benralizumab. The number of mucus plugs was correlated with sputum eosinophil percentage and eosinophil cationic protein in the sputum supernatants and inversely correlated with forced expiratory volume in 1 s (FEV1). Benralizumab induction resulted in a marked decrease in blood and sputum eosinophil levels and a significant improvement in asthma symptoms, quality of life scores, FEV1, and exacerbation frequency. Furthermore, there was a significant correlation between the reduction in mucus plugs and changes in the symptom score or FEV1.

DISCUSSION/CONCLUSION

These data suggest that benralizumab may have the potential to improve symptoms and respiratory function in patients with severe eosinophilic asthma by reducing mucus plugs.

Eosinophil: A New Circulating Biomarker for Risk of Poor Outcome in Stroke Patients Undergoing Mechanical Thrombectomy

Objective

Acute ischemic stroke (AIS), caused by occlusion of large vessel, is a serious life-threatening disease. This study aimed to comprehensively investigate the association of 14 common and readily available circulating biomarkers with the 90-day modified Rankin Scale (mRS) score in patients undergoing mechanical thrombectomy (MT).

Methods

This study included patients with anterior circulation large vessel occlusive stroke treated with MT from 05/2017 to 12/2021. Baseline comparisons of poor outcome were performed among enrolled patients. Factors that may be associated with the mRS score were assessed using correlation analysis. Univariate and multivariate logistic regression analyses were used to evaluate the predictive value of circulating biomarkers and poor outcome.

Results

The mRS score has a strong correlation with neutrophil to lymphocyte ratio (NLR) and eosinophil levels (all r_s>0.4 in absolute value and all P<0.001) in addition to a high correlation with National Institute of Health Stroke Scale (NIHSS) score (r_s=0.40, P<0.001). There was also a high correlation between NLR and eosinophil (r_s=-0.58, P<0.001). In the multivariate regression analysis, only neutrophil (adjusted OR=1.301, 95% CI: 1.155-1.465, P<0.001), eosinophil (adjusted OR<0.001, 95% CI: <0.001-0.016, P<0.001), and NLR (adjusted OR=1.158, 95% CI: 1.082-1.241, P<0.001) were independently associated with poor outcome.

Conclusion

This study evaluated a series of circulating biomarkers and found that neutrophil, eosinophil, and NLR independently predicted poor outcome after MT in AIS patients. There was a significant negative correlation between eosinophil and NLR levels.

Combinational System of Lipid-Based Nanocarriers and Biodegradable Polymers for Wound Healing: An Updated Review

Skin wounds have imposed serious socioeconomic burdens on healthcare providers and patients. There are just more than 25,000 burn injury-related deaths reported each year. Conventional treatments do not often allow the re-establishment of the function of affected regions and structures, resulting in dehydration and wound infections. Many nanocarriers, such as lipid-based systems or biobased and biodegradable polymers and their associated platforms, are favorable in wound healing due to their ability to promote cell adhesion and migration, thus improving wound healing and reducing scarring. Hence, many researchers have focused on developing new wound dressings based on such compounds with desirable effects. However, when applied in wound healing, some problems occur, such as the high cost of public health, novel treatments emphasizing reduced healthcare costs, and increasing quality of treatment outcomes. The integrated hybrid systems of lipid-based nanocarriers (LNCs) and polymer-based systems can be promising as the solution for the above problems in the wound healing process. Furthermore, novel drug delivery systems showed more effective release of therapeutic agents, suitable mimicking of the physiological environment, and improvement in the function of the single system. This review highlights recent advances in lipid-based systems and the role of lipid-based carriers and biodegradable polymers in wound healing.

Diagnosis and Rationale for Action against Cow's Milk Allergy (DRACMA) Guidelines update - III - Cow's milk allergens and mechanisms triggering immune activation

Background

The immunopathogenesis of cow's milk protein allergy (CMPA) is based on different mechanisms related to immune recognition of protein epitopes, which are affected by industrial processing.

Purpose

The purpose of this WAO DRACMA paper is to: (i) give a comprehensive overview of milk protein allergens, (ii) to review their immunogenicity and allergenicity in the context of industrial processing, and (iii) to review the milk-related immune mechanisms triggering IgE-mediated immediate type hypersensitivity reactions, mixed reactions and non-IgE mediated hypersensitivities.

Results

The main cow’s milk allergens – α-lactalbumin, β-lactoglobulin, serum albumin, caseins, bovine serum albumins, and others – may determine allergic reactions through a range of mechanisms. All marketed milk and milk products have undergone industrial processing that involves heating, filtration, and defatting. Milk processing results in structural changes of immunomodulatory proteins, leads to a loss of lipophilic compounds in the matrix, and hence to a higher allergenicity of industrially processed milk products. Thereby, the tolerogenic capacity of raw farm milk, associated with the whey proteins α-lactalbumin and β-lactoglobulin and their lipophilic ligands, is lost.

Conclusion

The spectrum of immunopathogenic mechanisms underlying cow's milk allergy (CMA) is wide. Unprocessed, fresh cow's milk, like human breast milk, contains various tolerogenic factors that are impaired by industrial processing. Further studies focusing on the immunological consequences of milk processing are warranted to understand on a molecular basis to what extent processing procedures make single milk compounds into allergens.

T cell activation and bacterial infection in skin wounds of recessive dystrophic epidermolysis bullosa patients

Recessive dystrophic epidermolysis bullosa (RDEB) patients develop poorly healing skin wounds that are frequently colonized with microbiota. Because T cells play an important role in clearing such pathogens, we aimed to define the status of adaptive T cell‐mediated immunity in RDEB wounds. Using a non‐invasive approach for sampling of wound‐associated constituents, we evaluated microbial contaminants in cellular fraction and exudates obtained from RDED wounds. Infectivity and intracellular trafficking of inactivated Staphylococcus aureus was accessed in RDEB keratinocytes. S. aureus and microbial antigen‐specific activation of RDEB wound‐derived T cells were investigated by fluorescence‐activated cell sorting‐based immune‐phenotyping and T‐cell functional assays. We found that RDEB wounds and epithelial cells are most frequently infected with Staphylococcus sp. and Pseudomonas sp. and that S. aureus essentially infects more RDEB keratinocytes and RDEB‐derived squamous cell carcinoma cells than keratinocytes from healthy donors. The RDEB wound‐associated T cells contain populations of CD4⁺ and CD8⁺ peripheral memory T cells that respond to soluble microbial antigens by proliferating and secreting interferon gamma (IFNγ). Moreover, CD8⁺ cytotoxic T lymphocytes recognize S. aureus‐infected RDEB keratinocytes and respond by producing interleukin‐2 (IL‐2) and IFNγ and degranulating and cytotoxically killing infected cells. Prolonged exposure of RDEB‐derived T cells to microbial antigens in vitro does not trigger PD‐1‐mediated T‐cell exhaustion but induces differentiation of the CD4^high population into CD4^highCD25⁺FoxP3⁺ regulatory T cells. Our data demonstrated that adaptive T cell‐mediated immunity could clear infected cells from wound sites, but these effects might be inhibited by PD‐1/Treg‐mediated immuno‐suppression in RDEB.

Dietary L-Carnitine Affects Leukocyte Count and Function in Dairy Cows Around Parturition

In early lactation, an energy deficit leading to a negative energy balance (NEB) is associated with increased susceptibility to disease and has been shown to be an important factor during transition in dairy cows. L-carnitine as a key factor in the mitochondrial transport of fatty acids and subsequently for β-oxidation and energy release is known to modulate mitochondrial biogenesis and thus influence metabolism and immune system. In the current study, we characterized hematological changes around parturition and investigated the potential effects of dietary L-carnitine supplementation on immune cell functions. For this approach, dairy cows were assigned either to a control (CON, n = 30) or an L-carnitine group [CAR, n = 29, 25 g rumen-protected L-carnitine per cow and day (d)]. Blood samples were taken from d 42 ante partum (ap) until d 110 post-partum (pp), with special focus and frequent sampling from 0.5 to72 h post-calving to clarify the impact of L-carnitine supplementation on leukocyte count, formation of reactive oxygen species (ROS) in polymorphonuclear cells (PMN) and peripheral mononuclear cells (PBMC) and their phagocytosis activity. Blood cortisol concentration and the capacity of PBMC proliferation was also investigated. All populations of leukocytes were changed during the peripartal period, especially granulocytes showed a characteristic increase up to 4 h pp. L-carnitine supplementation resulted in increased levels of eosinophils which was particularly pronounced one day before to 4 h pp, indicating a possible enhanced support for tissue repair and recovery. Non-supplemented cows showed a higher phagocytic activity in PBMC as well as a higher phagocytic capacity of PMN during the most demanding period around parturition, which may relate to a decrease in plasma levels of non-esterified fatty acids reported previously. L-carnitine, on the other hand, led to an increased efficiency to form ROS in stimulated PMN. Finally, a short period around calving proved to be a sensitive period in which L-carnitine administration was effective.

The aryl hydrocarbon receptor contributes to tissue adaptation of intestinal eosinophils in mice

Eosinophils are potent sources of inflammatory and toxic mediators, yet they reside in large numbers in the healthy intestine without causing tissue damage. We show here that intestinal eosinophils were specifically adapted to their environment and underwent substantial transcriptomic changes. Intestinal eosinophils upregulated genes relating to the immune response, cell-cell communication, extracellular matrix remodeling, and the aryl hydrocarbon receptor (AHR), a ligand-activated transcription factor with broad functions in intestinal homeostasis. Eosinophils from AHR-deficient mice failed to fully express the intestinal gene expression program, including extracellular matrix organization and cell junction pathways. AHR-deficient eosinophils were functionally impaired in the adhesion to and degradation of extracellular matrix, were more prone to degranulation, and had an extended life span. Lack of AHR in eosinophils had wider effects on the intestinal immune system, affecting the T cell compartment in nave and helminth-infected mice. Our study demonstrates that the response to environmental triggers via AHR partially shapes tissue adaptation of eosinophils in the small intestine.

Eosinophilic airway diseases: basic science, clinical manifestations and future challenges

Eosinophils have a broad range of functions, both homeostatic and pathological, mediated through an array of cell surface receptors and specific secretory granules that promote interactions with their microenvironment. Eosinophil development, differentiation, activation, survival and recruitment are closely regulated by a number of type 2 cytokines, including interleukin (IL)-5, the key driver of eosinophilopoiesis. Evidence shows that type 2 inflammation, driven mainly by interleukin (IL)-4, IL-5 and IL-13, plays an important role in the pathophysiology of eosinophilic airway diseases, including asthma, chronic rhinosinusitis with nasal polyps, eosinophilic granulomatosis with polyangiitis and hypereosinophilic syndrome. Several biologic therapies have been developed to suppress type 2 inflammation, namely mepolizumab, reslizumab, benralizumab, dupilumab, omalizumab and tezepelumab. While these therapies have been associated with clinical benefits in a range of eosinophilic diseases, their development has highlighted several challenges and directions for future research. These include the need for further information on disease progression and identification of treatable traits, including clinical characteristics or biomarkers that will improve the prediction of treatment response. The Nordic countries have a long tradition of collaboration using patient registries and Nordic asthma registries provide unique opportunities to address these research questions. One example of such a registry is the NORdic Dataset for aSThmA Research (NORDSTAR), a longitudinal population-based dataset containing all 3.3 million individuals with asthma from four Nordic countries (Denmark, Finland, Norway and Sweden). Large-scale, real-world registry data such as those from Nordic countries may provide important information regarding the progression of eosinophilic asthma, in addition to clinical characteristics or biomarkers that could allow targeted treatment and ensure optimal patient outcomes.

Coiled Coil Crosslinked Alginate Hydrogels Dampen Macrophage-Driven Inflammation

Alginate hydrogels are widely used for tissue engineering and regenerative medicine due to their excellent biocompatibility. A facile and commonly used strategy to crosslink alginate is the addition of Ca²⁺ that leads to hydrogelation. However, extracellular Ca²⁺ is a secondary messenger in activating inflammasome pathways following physical injury or pathogenic insult, which carries the risk of persistent inflammation and scaffold rejection. Here, we present graft copolymers of charge complementary heterodimeric coiled coil (CC) peptides and alginate that undergo supramolecular self-assembly to form Ca²⁺ free alginate hydrogels. The formation of heterodimeric CCs was confirmed using circular dichroism spectroscopy, and scanning electron microscopy revealed a significant difference in crosslink density and homogeneity between Ca²⁺ and CC crosslinked gels. The resulting hydrogels were self-supporting and display shear-thinning and shear-recovery properties. In response to lipopolysaccharide (LPS) stimulation, peritoneal macrophages and bone marrow-derived dendritic cells cultured in the CC crosslinked gels exhibited a 10-fold reduction in secretion of the proinflammatory cytokine IL-1β compared to Ca²⁺ crosslinked gels. A similar response was also observed in vivo upon peritoneal delivery of Ca²⁺ or CC crosslinked gels. Analysis of peritoneal lavage showed that macrophages in mice injected with Ca²⁺ crosslinked gels display a more inflammatory phenotype compared to macrophages from mice injected with CC crosslinked gels. These results suggest that CC peptides by virtue of their tunable sequence-structure-function relationship and mild gelation conditions are promising alternative crosslinkers for alginate and other biopolymer scaffolds used in tissue engineering.

Epithelial-Cell-Derived Extracellular Vesicles in Pathophysiology of Epithelial Injury and Repair in Chronic Rhinosinusitis: Connecting Immunology in Research Lab to Biomarkers in Clinics

Epithelial barrier disruption and failure of epithelial repair by aberrant epithelial-mesenchymal transition (EMT)-induced basal cells observed in nasal mucosa of chronic rhinosinusitis (CRS) are speculated to play important roles in disease pathophysiology. Microparticles (MPs) are a type of extracellular vesicle (EV) released by budding or shedding from the plasma membrane of activated or apoptotic cells. MPs are detected in nasal lavage fluids (NLFs) and are now receiving attention as potential biomarkers to evaluate the degree of activation of immune cells and injury of structural cells in nasal mucosa of subjects with sinus disease. There are three types of epithelial-cell-derived MPs, which are defined by the expression of different epithelial specific markers on their surface: EpCAM, E-cadherin, and integrin β6 (ITGB6). When these markers are on MPs that are also carrying canonical EMT/mesenchymal markers (Snail (SNAI1); Slug (SNAI2); alpha-smooth muscle actin (αSMA, ACTA2)) or pro- and anti-coagulant molecules (tissue factor (TF); tissue plasminogen activator (tPA); plasminogen activator inhibitor-1 (PAI-1)), they provide insight as to the roles of epithelial activation for EMT or regulation of coagulation in the underlying disease. In this review, we discuss the potential of epithelial MPs as research tools to evaluate status of nasal mucosae of CRS patients in the lab, as well as biomarkers for management and treatment of CRS in the clinic.

Finding Solutions for Fibrosis: Understanding the Innate Mechanisms Used by Super-Regenerator Vertebrates to Combat Scarring

Soft tissue fibrosis and cutaneous scarring represent massive clinical burdens to millions of patients per year and the therapeutic options available are currently quite limited. Despite what is known about the process of fibrosis in mammals, novel approaches for combating fibrosis and scarring are necessary. It is hypothesized that scarring has evolved as a solution to maximize healing speed to reduce fluid loss and infection. This hypothesis, however, is complicated by regenerative animals, which have arguably the most remarkable healing abilities and are capable of scar-free healing. This review explores the differences observed between adult mammalian healing that typically results in fibrosis versus healing in regenerative animals that heal scarlessly. Each stage of wound healing is surveyed in depth from the perspective of many regenerative and fibrotic healers so as to identify the most important molecular and physiological variances along the way to disparate injury repair outcomes. Understanding how these powerful model systems accomplish the feat of scar-free healing may provide critical therapeutic approaches to the treatment or prevention of fibrosis.

Reparative and Maladaptive Inflammation in Tendon Healing

Tendon injuries are common and debilitating, with non-regenerative healing often resulting in chronic disease. While there has been considerable progress in identifying the cellular and molecular regulators of tendon healing, the role of inflammation in tendon healing is less well understood. While inflammation underlies chronic tendinopathy, it also aids debris clearance and signals tissue repair. Here, we highlight recent findings in this area, focusing on the cells and cytokines involved in reparative inflammation. We also discuss findings from other model systems when research in tendon is minimal, and explore recent studies in the treatment of human tendinopathy to glean further insights into the immunobiology of tendon healing.

Eosinophil-to-Neutrophil Ratio Predicts Poor Prognosis of Acute Ischemic Stroke Patients Treated With Intravenous Thrombolysis

Background and Purpose: The eosinophil-to-neutrophil ratio (ENR) was recently reported as a novel inflammatory marker in acute ischemic stroke (AIS). However, few studies reported the predictive value of ENR in AIS patients, especially for those with intravenous thrombolysis.

Methods: Two hundred sixty-six AIS patients receiving intravenous thrombolysis were retrospectively recruited in this study and followed up for 3 months and 1 year. The Modified Rankin Scale (mRS) and the time of death were recorded. Poor outcome was defined as mRS 3–6. After excluding patients who were lost to follow-up, the remaining 250 patients were included in the 3-month prognosis analysis and the remaining 223 patients were included in the 1-year prognosis analysis.

Results: ENR levels in the patients were lower than those in the healthy controls. The optimal cutoff values for the ability of ENR × 10² to predict 3-month poor outcome were 0.74 with 67.8% sensitivity and 77.3% specificity. Patients with ENR × 10² ≥ 0.74 have a lower baseline National Institutes of Health Stroke Scale (NIHSS) score (median: 7 vs. 11, p < 0.001). After multivariate adjustment, patients with ENR × 10² ≥ 0.74 were more likely to come to a better 3-month outcome (OR = 0.163; 95% CI, 0.076–0.348, p < 0.001). At the 1-year follow-up, the patients with ENR × 10² ≥ 0.74 showed a lower risk of mortality (HR = 0.314; 95% CI, 0.135–0.731; p = 0.007).

Conclusions: A lower ENR is independently associated with a 3-month poor outcome and a 3-month and 1-year mortality in AIS patients treated with intravenous thrombolysis.

Dynamic Decrease in Eosinophil After Intravenous Thrombolysis Predicts Poor Prognosis of Acute Ischemic Stroke: A Longitudinal Study

Background and Purpose

Blood eosinophil counts are thought to be associated with atherosclerosis in acute ischemic stroke (AIS) and AIS severity. We aimed to investigate 1): the temporal profile of eosinophil in AIS patients treated with recombinant tissue plasminogen activator (r-tPA); 2): The association between dynamic eosinophil and 3-month outcomes in different AIS etiologies; 3): incremental predictive ability of dynamic eosinophil adding to conventional model; and 4): the longitudinal change of neutrophil-to-lymphocyte ratio (NLR) and compared its prognostic value with eosinophils.

Methods

A total of 623 AIS patients with intravenous thrombolysis in two hospitals were included. Blood samples were obtained on admission, within 24 h after an intravenous thrombolysis and on the seventh day. A multivariate logistic regression model with restricted cubic spline was performed to explore the association between dynamic eosinophil and a 3-month poor outcome. C-statistic, net reclassification improvement (NRI) and integrated discrimination improvement (IDI) were adopted to explore the incremental predictive ability.

Results

Percent change in eosinophil counts after intravenous thrombolysis was median -25.00% (IQR -68.25%-+14.29%). Decrease in eosinophil >75% after intravenous thrombolysis was associated with 2.585 times risk for poor outcome and 13.836 times risk for death. However, the association were weak for patients outside of cardioembolic stroke. Adding eosinophil changes to a conventional model improved the discriminatory ability of poor outcome (NRI = 53.3%; IDI = 2.2%) and death (NRI = 101.0%; IDI = 6.9%).

Conclusions

Dynamic decrease in eosinophil after intravenous thrombolysis predicts a 3-month poor outcome and death in AIS patients with r-tPA treatment and improved the predictive ability of conventional model. However, this result needs to be interpreted carefully in non-cardioembolic AIS patients.

The Effect of a Triple Combination of Bevacizumab, Sodium Hyaluronate and a Collagen Matrix Implant in a Trabeculectomy Animal Model

Currently available anti-scarring treatments for glaucoma filtration surgery (GFS) have potentially blinding complications, so there is a need for alternative and safer agents. The effects of the intrableb administration of a new combination of the anti-VEGF bevacizumab, sodium hyaluronate and a collagen matrix implant were investigated in a rabbit model of GFS, with the purpose of modulating inflammation, angiogenesis, fibroblast migration and fibrogenesis in the wound healing process. A comparative-effectiveness study was performed with twenty-four rabbits, randomly assigned to the following treatments: (a) biodegradable collagen matrix implant (Olo), (b) bevacizumab-loaded collagen matrix implant (Olo-BVZ), (c) bevacizumab-loaded collagen matrix implant combined with sodium hyaluronate (Olo-BVZ-H5) and (d) sham-operated animals (control). Rabbits underwent a conventional trabeculectomy and were studied over 30 days in terms of intraocular pressure and bleb characterization (height, area and vascularity in central, peripheral and non-bleb zones). Histologic differences among groups were further evaluated at day 30 (inflammation, total cellularity and degree of fibrosis in the area of surgery). Local delivery of bevacizumab (Olo-BVZ and Olo-BVZ-H5) increased the survival of the filtering bleb by 21% and 31%, respectively, and generated a significant decrease in inflammation and cell infiltration histologically 30 days after surgery, without exhibiting any local toxic effects. Olo-BVZ-H5 showed less lymphocyte infiltration and inflammation than the rest of the treatments. Intraoperative intrableb implantation of bevacizumab, sodium hyaluronate and a collagen matrix may provide an improved trabeculectomy outcome in this model of intense wound healing. This study showed an effective procedure with few surgical complications and a novel combination of active compounds that offer new possibilities to improve the efficacy of filtration surgery.

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

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

High Eosinophil Rates in Patients With Right-to-Left Shunts: An Expected Role, or an Unexpected Risk?

Background and objective Eosinophils are associated with thromboembolic events. Since eosinophils are eliminated in the pulmonary vasculature, right-to-left shunt (RLS) through patent foramen ovale may increase eosinophils in the peripheral blood. In this report, we evaluated the eosinophils of patients with regard to the presence of RLS and its quantity. Patients and methods In this retrospective observational study, we analyzed the complete blood cell count (CBC) of patients with RLS (n=47) and without RLS (n=31) diagnosed by contrast echocardiography (CE). RLS was identified as mild (5-10 bubbles) and moderate shunt (10-25 bubbles). Results Age and CBC were not significantly different between the groups, with the exception of eosinophils. Patients with RLS had higher eosinophils percentage compared to patients without RLS (3.1 ±1.5 vs. 1.7 ±0.7, p=0.001). Additionally, eosinophils percentage was significantly higher in the mild RLS group (2.4 ±0.9 vs. 1.7 ±0.7, p=0.016) and the moderate RLS group (4.3 ±1.6 vs. 1.7 ±0.7, p=0.001) compared to normal subjects. Also, it was significantly higher in the moderate RLS group compared to the mild group (4.3 ±1.6 vs. 2.4 ±0.9, p=0.001). Conclusions Eosinophils percentage was higher in patients with mild and moderate RLS compared to normal individuals. Moreover, the eosinophil rate was higher in patients with moderate RLS than in patients with mild RLS.

Injection site vaccinology of a recombinant vaccinia-based vector reveals diverse innate immune signatures

Poxvirus systems have been extensively used as vaccine vectors. Herein a RNA-Seq analysis of intramuscular injection sites provided detailed insights into host innate immune responses, as well as expression of vector and recombinant immunogen genes, after vaccination with a new multiplication defective, vaccinia-based vector, Sementis Copenhagen Vector. Chikungunya and Zika virus immunogen mRNA and protein expression was associated with necrosing skeletal muscle cells surrounded by mixed cellular infiltrates. The multiple adjuvant signatures at 12 hours post-vaccination were dominated by TLR3, 4 and 9, STING, MAVS, PKR and the inflammasome. Th1 cytokine signatures were dominated by IFNγ, TNF and IL1β, and chemokine signatures by CCL5 and CXCL12. Multiple signatures associated with dendritic cell stimulation were evident. By day seven, vaccine transcripts were absent, and cell death, neutrophil, macrophage and inflammation annotations had abated. No compelling arthritis signatures were identified. Such injection site vaccinology approaches should inform refinements in poxvirus-based vector design.

Poxvirus vector systems have been widely developed for vaccine applications. Despite considerable progress, so far only one recombinant poxvirus vectored vaccine has to date been licensed for human use, with ongoing efforts seeking to enhance immunogenicity whilst minimizing reactogenicity. The latter two characteristics are often determined by early post-vaccination events at the injection site. We therefore undertook an injection site vaccinology approach to analyzing gene expression at the vaccination site after intramuscular inoculation with a recombinant, multiplication defective, vaccinia-based vaccine. This provided detailed insights into inter alia expression of vector-encoded immunoregulatory genes, as well as host innate and adaptive immune responses. We propose that such injection site vaccinology can inform rational vaccine vector design, and we discuss how the information and approach elucidated herein might be used to improve immunogenicity and limit reactogenicity of poxvirus-based vaccine vector systems.

The multiple functions and subpopulations of eosinophils in tissues under steady-state and pathological conditions

Eosinophils not only play a critical role in the pathogenesis of eosinophil-associated diseases, but they also have multiple important biological functions, including the maintenance of homeostasis, host defense against infections, immune regulation through canonical Th1/Th2 balance modulation, and anti-inflammatory and anti-tumorigenic activities. Recent studies have elucidated some emerging roles of eosinophils in steady-state conditions; for example, eosinophils contribute to adipose tissue metabolism and metabolic health through alternatively activated macrophages and the maintenance of plasma cells in intestinal tissue and bone marrow. Moreover, eosinophils exert tissue damage through eosinophil-derived cytotoxic mediators that are involved in eosinophilic airway inflammation, leading to diseases including asthma and chronic rhinosinusitis with nasal polyps characterized by fibrin deposition through excessive response by eosinophils-induced. Thus, eosinophils possessing these various effects reflect the heterogenous features of these cells, which suggests the existence of distinct different subpopulations of eosinophils between steady-state and pathological conditions. Indeed, a recent study demonstrated that instead of dividing eosinophils by classical morphological changes into normodense and hypodense eosinophils, murine eosinophils from lung tissue can be phenotypically divided into two distinct subtypes: resident eosinophils and inducible eosinophils gated by Siglec-F^int CD62L⁺ CD101^low and Siglec-F^high CD62L^- CD101^high, respectively. However, it is difficult to explain every function of eosinophils by rEos and iEos, and the relationship between the functions and subpopulations of eosinophils remains controversial. Here, we overview the multiple roles of eosinophils in the tissue and their biological behavior in steady-state and pathological conditions. We also discuss eosinophil subpopulations.