Eosinophils in the pathogenesis of pancreatic disorders

Pancreatic Eosinophilic Infiltrates of Infants of Diabetic Mothers Revisited

Background: Infants of diabetic mothers (IDM) frequently show eosinophilic infiltrates around the pancreatic islets. We review 2 IDM, describe the pancreatic histology and review the literature. Case reports: Two term IDM died at 1 h and 43 days respectively. Both had eosinophilic infiltrates with frequent Charcot Leyden crystals surrounding the primary islets, had occasional eosinophils in these primary islets, but the infiltrate spared the acini and the intralobular islet tissue. There was no necrosis, fibrosis, or vasculitis. From the literature, this has been described as early as 28 weeks gestation, and occasionally was associated with peri-islet fibrosis. Conclusion: This infiltrate occurs antenatally, surrounds the primary islets, spares intralobular islet cells, persists past the neonatal period, and is not uniformly associated with islet or peri-islet injury. As eosinophils contribute to a variety of pancreatic inflammatory conditions, investigation may lead to further insights into the effect of maternal diabetes on the infant.

Practical concepts and strategies for early diagnosis and management of eosinophilic gastrointestinal disorders in East-Asian children

Eosinophilic gastrointestinal disorders (EGIDs) are emerging as significant concerns in the Korean pediatric population and transitioning from rare to more commonly diagnosed conditions. This review discusses the increasing prevalence of EGID among children and adolescents and highlights the complexities involved in its diagnosis and management. This review begins with a thorough examination of the diverse clinical presentations of EGIDs in Korean children, with a special focus on common gastrointestinal symptoms such as abdominal pain, diarrhea, and bloody stool. Additionally, we explored extraintestinal manifestations, including growth failure, malnutrition, and associated allergic comorbidities, highlighting their importance in the clinical landscape of EGIDs. Because of its subtle and overlapping symptoms with those of other gastrointestinal disorders, EGID is frequently underdiagnosed. Addressing this challenge requires maintaining a high index of suspicion and employing a comprehensive diagnostic approach to differentiating EGID from functional gastrointestinal disorders and other inflammatory or systemic diseases such as inflammatory bowel disease. The optimal management of EGID requires a collaborative multidisciplinary strategy that includes dietary management, regular monitoring, and tailored medical interventions. This review emphasizes the importance of proactive patient and caregiver education and regular follow-ups to improve long-term outcomes in affected children. Enhanced awareness among healthcare providers and better educational resources for families are critical for the early identification and effective management of EGID among pediatric patients.

Review of Peripheral Blood Eosinophilia: Workup and Differential Diagnosis

Eosinophils are a type of granulocyte key to immune system modulation seen in a number of disease processes. Nearly every major organ system can be connected to peripheral eosinophilia through a number of different disease processes, ranging from benign conditions to malignancy. In this paper, we review both common and rare causes of peripheral eosinophilia, their symptoms, and a framework for the workup of peripheral eosinophilia of unknown etiology.

Eosinophils in obesity and obesity-associated disorders

Despite the rising prevalence and costs for the society, obesity etiology, and its precise cellular and molecular mechanisms are still insufficiently understood. The excessive accumulation of fat by adipocytes plays a key role in obesity progression and has many repercussions on total body physiology. In recent years the immune system as a gatekeeper of adipose tissue homeostasis has been evidenced and has become a focal point of research. Herein we focus on eosinophils, an important component of type 2 immunity, assuming fundamental, yet ill-defined, roles in the genesis, and progression of obesity and related metabolic disorders. We summarize eosinophilopoiesis and eosinophils recruitment into adipose tissue and discuss how the adipose tissue environments shape their function and vice versa. Finally, we also detail how obesity transforms the local eosinophil niche. Understanding eosinophil crosstalk with the diverse cell types within the adipose tissue environment will allow us to framework the therapeutic potential of eosinophils in obesity.

Allergen-induced NLRP3/caspase1/IL-18 signaling initiate eosinophilic esophagitis and respective inhibitors protect disease pathogenesis

The current report describes a stepwise mechanistic pathway of NLRP3/caspase1/IL-18-regulated immune responses operational in eosinophilic esophagitis (EoE). We show that esophageal epithelial cells and macrophage-derived NLRP3 regulated IL-18 initiate the disease and induced IL-5 facilitates eosinophil growth and survival. We also found that A. fumigatus-exposed IL-18-/- mice or IL-18-neutralized mice are protected from EoE induction. Most importantly, we present that intravascular rIL-18 delivery to ΔdblGATA mice and CD2-IL-5 mice show the development of EoE characteristics feature like degranulated and intraepithelial eosinophils, basal cell hyperplasia, remodeling and fibrosis. Similarly, we show an induced NLRP3-caspase1-regulated IL-18 pathway is also operational in human EoE. Lastly, we present the evidence that inhibitors of NLRP3 and caspase-1 (MCC950, BHB, and VX-765) protect A. fumigatus- and corn-extract-induced EoE pathogenesis. In conclusion, the current study provides a new understanding by implicating NLRP3/caspase1-regulated IL-18 pathway in EoE pathogenesis. The study has the clinical significance and novel therapeutic strategy, which depletes only IL-18-responsive pathogenic eosinophils, not naïve IL-5-generated eosinophils critical for maintaining innate immunity.

Fluorescent molecular probes for imaging and detection of oxidases and peroxidases in biological samples

Oxidases and peroxidases are two subclasses of oxidoreductases. The abnormal expression of oxidases (such as tyrosinase, cytochrome P450 oxidases, and monoamine oxidases) and peroxidases (such as glutathione peroxidase, myeloperoxidase, and eosinophil peroxidase) is relative with some diseases. Therefore, the analysis of oxidases and peroxidases is great important for disease diagnosis and treatment. Fluorescent probes present simple protocol, high sensitivity and good stability in sensing field. Molecule fluorescent probes are constructed with chemical groups that tunes their fluorescence emission in response to binding events, chemical reactions, and the surrounding environment. A fluorescent probe is an efficient tool for visualizing the activity of enzymes in living organisms on the basis of its high specificity, sensitivity, and noninvasiveness characteristics. In this review, we focus on the sensing of oxidases and peroxidases by molecule fluorescent probes, and hope to bring new insight to wide researchers about oxidases and peroxidases in biological samples.

Pediatric Autoimmune Pancreatitis: A Single-Center Retrospective Case Series

OBJECTIVES

Autoimmune pancreatitis (AIP) is a rare form of a chronic, immune-mediated, inflammatory pancreatic condition. There is limited data regarding presentation and outcome in the pediatric population. We described a single-center case series of 4 pediatric patients with AIP to better understand the presentation, symptoms, and outcomes of this rare condition.

METHODS

Data collected included demographics, serology markers, symptoms at presentation, imaging, additional organ involvement, histology, treatment methods, and outcomes. The diagnosis of AIP was made by a combination of serology, pancreatic imaging, histology, extrapancreatic manifestations, and steroid response.

RESULTS

All patients were diagnosed with type 2 AIP. Abdominal pain, emesis, and obstructive jaundice were the most common symptoms at presentation. Autoimmune markers were negative. Cross-sectional abdominal imaging showed diffuse/focal pancreatic gland enlargement and common bile duct stricture universally and main pancreatic duct irregularity in half of the patients. Biopsies showed lymphoplasmacytic infiltration with associated pancreatic fibrosis and atrophy. Treatment with an 8-week tapering course of prednisone showed prompt response with resolution of symptoms and normalization of laboratory test results.

CONCLUSIONS

Our case series shows that AIP in children is a rare entity with a distinct clinical presentation, classical radiographic and histological features with good long-term prognosis.

Expression of DEL-1 in alveolar epithelial cells prevents lipopolysaccharide-induced inflammation, oxidative stress, and eosinophil recruitment in acute lung injury

Bacterial infection is a major cause of acute lung injury (ALI). Developmental endothelial locus-1 (DEL-1) is an immunomodulatory mediator secreted by the endothelial cells. This study aimed to investigate the role of DEL-1 in lipopolysaccharide (LPS)-induced ALI in mouse models and its ability to regulate on eosinophil recruitment. Male C57BL/6 mice were administered an adeno-associated virus (AAV)-mediated DEL-1 overexpression vector via intratracheal injection. Twenty-one days after vector instillation, mice were challenged with LPS (5 mg/kg body weight). Lung injury was evaluated using haematoxylin-eosin staining, flow cytometry, enzyme-linked immunosorbnent assay, quantitative real-time polymerase chain reaction, western blotting, immunohistochemistry and immunofluorescence analyses. DEL-1 was expressed in alveolar epithelial cells of mice. Compared with that in the control group, DEL-1 was expressed at low levels in the lungs of LPS-challenged mice. LPS injured the lungs in mice, as evidenced by an increase in alveolar wall thickness, inflammatory cell infiltration in the stroma, and alveolar collapse. AAV-mediated DEL-1 overexpression attenuated LPS-induced lung injury and inhibited the release of TNF-α, IL-6, and IL-1β. DEL-1 overexpression also attenuated LPS-induced oxidative stress by decreasing lactic dehydrogenase (LDH), myeloperoxidase (MPO), malondialdehyde (MDA), and reactive oxygen species (ROS) activities and increasing superoxide dismutase (SOD) activity. In addition, DEL-1 prevented eosinophil recruitment into lung tissues and inhibited eotaxin production. This study revealed the beneficial role of DEL-1 in preventing LPS-induced ALI in mice. Therefore, DEL-1 can protect lung tissues against LPS-induced inflammation, oxidative stress, and eosinophil recruitment.

Emerging Evidence for Pleiotropism of Eosinophils

Eosinophils are complex granulocytes with the capacity to react upon diverse stimuli due to their numerous and variable surface receptors, which allows them to respond in very different manners. Traditionally believed to be only part of parasitic and allergic/asthmatic immune responses, as scientific studies arise, the paradigm about these cells is continuously changing, adding layers of complexity to their roles in homeostasis and disease. Developing principally in the bone marrow by the action of IL-5 and granulocyte macrophage colony-stimulating factor GM-CSF, eosinophils migrate from the blood to very different organs, performing multiple functions in tissue homeostasis as in the gastrointestinal tract, thymus, uterus, mammary glands, liver, and skeletal muscle. In organs such as the lungs and gastrointestinal tract, eosinophils are able to act as immune regulatory cells and also to perform direct actions against parasites, and bacteria, where novel mechanisms of immune defense as extracellular DNA traps are key factors. Besides, eosinophils, are of importance in an effective response against viral pathogens by their nuclease enzymatic activity and have been lately described as involved in severe acute respiratory syndrome coronavirus SARS-CoV-2 immunity. The pleiotropic role of eosinophils is sustained because eosinophils can be also detrimental to human physiology, for example, in diseases like allergies, asthma, and eosinophilic esophagitis, where exosomes can be significant pathophysiologic units. These eosinophilic pathologies, require specific treatments by eosinophils control, such as new monoclonal antibodies like mepolizumab, reslizumab, and benralizumab. In this review, we describe the roles of eosinophils as effectors and regulatory cells and their involvement in pathological disorders and treatment.

Macrophages-induced IL-18-mediated eosinophilia promotes characteristics of pancreatic malignancy

The current study presents first CP murine model that show IL-18–induced eosinophil inflammation-mediated induction of oncogenic proteins and several pathological malignant characteristics.

Reports indicate that accumulated macrophages in the pancreas are responsible for promoting the pathogenesis of chronic pancreatitis (CP). Recently, macrophage-secreted cytokines have been implicated in promoting pancreatic acinar-to-ductal metaplasia (ADM). This study aims to establish the role of accumulated macrophage-activated NLRP3-IL-18-eosinophil mechanistic pathway in promoting several characteristics of pancreatic malignancy in CP. We report that in a murine model of pancreatic cancer (PC), accumulated macrophages are the source of NLRP3-regulated IL-18, which promotes eosinophilic inflammation-mediated accumulation to periductal mucin and collagen, including the formation of ADM, pancreatic intraepithelial neoplasia (PanINs), and intraductal papillary mucinous neoplasm. Most importantly, we show improved malignant characteristics with reduced levels of oncogenes in an anti–IL-18 neutralized and IL-18 gene deficient murine model of CP. Last, human biopsies validated that NLRP3-IL-18–induced eosinophils accumulate near the ducts, showing PanINs formation in PC. Taken together, we present the evidence on the role of IL-18–induced eosinophilia in the development of PC phenotype like ADM, PanINs, and ductal cell differentiation in inflammation-induced CP.