Aggregated eosinophils and neutrophils characterize the properties of mucus in chronic rhinosinusitis.

BACKGROUND: Airway obstruction caused by viscous mucus is an important pathophysiologic characteristic of persistent inflammation, which can result in organ damage. OBJECTIVE: We investigated the hypothesis that the biophysical characteristics of accumulating granulocytes affect the clinical properties of mucus. METHODS: Surgically acquired nasal mucus samples from patients with eosinophilic chronic rhinosinusitis and neutrophil-dominant, noneosinophilic chronic rhinosinusitis were evaluated in terms of computed tomography density, viscosity, water content, wettability, and protein composition. Isolated human eosinophils and neutrophils were stimulated to induce the formation of extracellular traps, followed by the formation of aggregates. The biophysical properties of the aggregated cells were also examined. RESULTS: Mucus from patients with eosinophilic chronic rhinosinusitis had significantly higher computed tomography density, viscosity, dry weight, and hydrophobicity compared to mucus from patients with noneosinophilic chronic rhinosinusitis. The levels of eosinophil-specific proteins in mucus correlated with its physical properties. Eosinophil and neutrophil aggregates showed physical and pathologic characteristics resembling those of mucus. Cotreatment with deoxyribonuclease and heparin, which slenderizes the structure of eosinophil extracellular traps, efficiently induced reductions in the viscosity and hydrophobicity of both eosinophil aggregates and eosinophilic mucus. CONCLUSIONS: The present study elucidated the pathogenesis of mucus stasis in infiltrated granulocyte aggregates from a novel perspective. These findings may contribute to the development of treatment strategies for eosinophilic airway diseases.

Improving performance and self-efficacy of novice nurses using hybrid simulation-based mastery learning.

AIM: Acute chest pain is a commonly encountered symptom in hospital medical/surgical units; however, almost half of nurses in their second year of clinical experience in our facility have reported struggling to care for acute chest pain patients. We developed, implemented, and examined the effectiveness of a simulation-based, mastery learning clinical nursing educational program to improve self-efficacy and performance in caring for patients with acute chest pain. METHODS: The study adopted a single-site, single-cohort design using simulation-based performance assessment and self-efficacy surveys on a convenience sample of 37 second-year clinical nurse participants in multi-stage hybrid mastery learning educational intervention using asynchronous e-learning, and hands-on simulation training and assessment with feedback on caring for chest pain patients. Performance assessments and self-efficacy surveys were administered pre-, post-, and 5 months post-intervention. RESULTS: Clinical performance on the post- and 5 months follow-up assessments were significantly higher than those for the pre-test (P < .0001). The self-efficacy scores for the post- and the 5 months follow-up assessments were significantly higher than the pre-course scores (P < .0001). Participants' self-efficacy perceptions were positively correlated with their performances at 5 months post-intervention. CONCLUSION: Performance and self-efficacy of novice nurses in caring for acute chest pain patients improved significantly with the multi-stage hybrid mastery learning educational intervention, with improvements retained 5 months post-intervention. The results suggest the applicability of simulation-based mastery learning in a clinical setting for novice nurses to attain specific skills, and raise their self-perception of competence to care for patients in acute settings.

A Patient Safety Champion Program for Interprofessional Health Care Educators: Implementation and Outcomes.

INTRODUCTION: Health care educators are challenged with helping clinicians develop competencies beyond their foundational training. In health care systems where continuing professional development is not integral to practice, clinicians may have few opportunities. We describe the design, implementation, and evaluation of a professional development program in patient safety for Japanese clinical educators to acquire simulation instructional skills and become Patient Safety Champions at their organizations. METHODS: Mixed methods were used in a longitudinal pre/post study design. The Kirkpatrick evaluation model was used to evaluate outcomes of a workshop, overall program, on-site training experiences, and impact as Patient Safety Champions. Self-assessment data on skills and knowledge of patient safety, simulation instructional methods, interprofessional collaboration, and leadership were collected and analyzed. RESULTS: Eighty-nine percent of participants facilitated on-site patient safety training within 6 months of workshop completion. Skills and knowledge improvement were observed immediately postworkshop in four categories: patient safety, simulation instructional methods, interprofessional collaboration and communication, and leadership as a patient safety champion. Skills and knowledge increased at 6 months after facilitation of on-site safety training. Program mean satisfaction scores ranged from 84% to 92%. Mean Patient Safety Champion in-facility evaluations were 4.2 to 4.7 on a 5-point scale. DISCUSSION: High levels of knowledge, skill retention, and behavior change are attributed to goal setting, outcome-oriented pedagogy, and reflective sessions. The Patient Safety Champion model and experiential learning approach gave Japanese clinical educators in medicine, nursing, and pharmacy an opportunity to learn from each other in simulations reflecting the practice environment.

Eosinophil-mediated inflammation in the absence of eosinophilia.

The increase of eosinophil levels is a hallmark of type-2 inflammation. Blood eosinophil counts act as a convenient biomarker for asthma phenotyping and the selection of biologics, and they are even used as a prognostic factor for severe coronavirus disease 2019. However, the circulating eosinophil count does not always reflect tissue eosinophilia and vice versa. The mismatch of blood and tissue eosinophilia can be seen in various clinical settings. For example, blood eosinophil levels in patients with acute eosinophilic pneumonia are often within normal range despite the marked symptoms and increased number of eosinophils in bronchoalveolar lavage fluid. Histological studies using immunostaining for eosinophil granule proteins have revealed the extracellular deposition of granule proteins coincident with pathological conditions, even in the absence of a significant eosinophil infiltrate. The marked deposition of eosinophil granule proteins in tissue is often associated with cytolytic degranulation. Recent studies have indicated that extracellular trap cell death (ETosis) is a major mechanism of cytolysis. Cytolytic ETosis is a total cell degranulation in which cytoplasmic and nuclear contents, including DNA and histones that act as alarmins, are also released. In the present review, eosinophil-mediated inflammation in such mismatch conditions is discussed.

The Curcumin Analog GO-Y030 Controls the Generation and Stability of Regulatory T Cells.

Regulatory T cells (Tregs) play a crucial role in preventing antitumor immune responses in cancer tissues. Cancer tissues produce large amounts of transforming growth factor beta (TGF-ß), which promotes the generation of Foxp3+ Tregs from naïve CD4+ T cells in the local tumor microenvironment. TGF-ß activates nuclear factor kappa B (NF-κB)/p300 and SMAD signaling, which increases the number of acetylated histones at the Foxp3 locus and induces Foxp3 gene expression. TGF-ß also helps stabilize Foxp3 expression. The curcumin analog and antitumor agent, GO-Y030, prevented the TGF-ß-induced generation of Tregs by preventing p300 from accelerating NF-κB-induced Foxp3 expression. Moreover, the addition of GO-Y030 resulted in a significant reduction in the number of acetylated histones at the Foxp3 promoter and at the conserved noncoding sequence 1 regions that are generated in response to TGF-ß. In vivo tumor models demonstrated that GO-Y030-treatment prevented tumor growth and reduced the Foxp3+ Tregs population in tumor-infiltrating lymphocytes. Therefore, GO-Y030 exerts a potent anticancer effect by controlling Treg generation and stability.

Clonal hematopoiesis in adult pure red cell aplasia.

Idiopathic pure red cell aplasia (PRCA) and secondary PRCA associated with thymoma and large granular lymphocyte leukemia are generally considered to be immune-mediated. The PRCA2004/2006 study showed that poor responses to immunosuppression and anemia relapse were associated with death. PRCA may represent the prodrome to MDS. Thus, clonal hematopoiesis may be responsible for treatment failure. We investigated gene mutations in myeloid neoplasm-associated genes in acquired PRCA. We identified 21 mutations affecting amino acid sequences in 11 of the 38 adult PRCA patients (28.9%) using stringent filtering of the error-prone sequences and SNPs. Four PRCA patients showed 7 driver mutations in TET2, DNMT3A and KDM6A, and 2 PRCA patients carried multiple mutations in TET2. Five PRCA patients had mutations with high VAFs exceeding 0.3. These results suggest that clonal hematopoiesis by stem/progenitor cells might be related to the pathophysiology of chronic PRCA in certain adult patients.

How to detect eosinophil ETosis (EETosis) and extracellular traps.

Eosinophils are short-lived and comprise only a small population of circulating leukocytes; however, they play surprisingly multifunctional roles in homeostasis and various diseases including allergy and infection. Recent research has shed light on active cytolytic eosinophil cell death that releases eosinophil extracellular traps (EETs) and total cellular contents, namely eosinophil extracellular trap cell death (EETosis). The pathological contribution of EETosis was made more cogent by recent findings that a classical pathological finding of eosinophilic inflammation, that of Charcot-Leyden crystals, is closely associated with EETosis. Currently no gold standard methods to identify EETosis exist, but "an active eosinophil lysis that releases cell-free granules and net-like chromatin structure" appears to be a common feature of EETosis. In this review, we describe several approaches that visualize EETs/EETosis in clinical samples and in vitro studies using isolated human eosinophils. EETs/EETosis can be observed using simple chemical or fluorescence staining, immunostaining, and electron microscopy, although it is noteworthy that visualization of EETs is greatly changed by sample preparation including the extracellular space of EETotic cells and shear flow. Considering the multiple aspects of biological significance, further study into EETs/EETosis is warranted to give a detailed understanding of the roles played in homeostasis and disease pathogenesis.

Distinguishing coagulase-negative Staphylococcus bacteremia from contamination using blood-culture positive bottle detection pattern and time to positivity.

AIM: Detection of coagulase-negative Staphylococcus in blood culture may be a result of either bacteremia or contamination. This often leads to diagnostic uncertainly. Our objective was to develop a method for differentiating whether a coagulase-negative Staphylococcus sp. positive blood culture represents bacteremia or contamination based on positive bottle detection pattern and time to positivity (TTP). METHODS: This study included 155 and 51 adults with positive blood cultures for Staphylococcus epidermidis and Staphylococcus hominis, respectively, over a three-year period from 2016 to 2018. Positive blood culture cases were categorized as either bacteremia or contamination based on the clinically available information, and the detection pattern and TTP in each category were investigated. RESULTS: A total of 57, 92, and 6 S. epidermidis positive blood cultures were categorized as bacteremia, contamination, and undetermined, respectively, whereas 15 and 36 S. hominis positive blood cultures were categorized as bacteremia and contamination, respectively. For positive blood cultures categorized as bacteremia, all four bottles in two sets of blood cultures were positive in 47/47 S. epidermidis and 14/14 S. hominis, respectively, whereas either one bottle in each of two sets or three bottles in two sets were positive in 10/19 S. epidermidis and 1/4 S. hominis, respectively; most of those TTPs were <48 h. Among them, the TTP in catheter-related blood stream infection was <24 h. CONCLUSION: Although clinical assessment is crucial to differentiate between bacteremia and contamination, a combination of positive bottle detection pattern and TTP is a valuable diagnostic auxiliary tool.

Fructo-oligosaccharides ameliorate steatohepatitis, visceral adiposity, and associated chronic inflammation via increased production of short-chain fatty acids in a mouse model of non-alcoholic steatohepatitis.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is a hepatic manifestation of metabolic syndrome. Within the spectrum of NAFLD, non-alcoholic steatohepatitis (NASH) in combination with hepatic inflammation and fibrosis can lead to liver cirrhosis and hepatocellular carcinoma. Dysbiosis was reported to contribute to NASH pathogenesis. This study aimed to determine the effects of fructo-oligosaccharides (FOS) on steatohepatitis and visceral adiposity in an obese mouse model of NASH. METHODS: Twelve newborn C57BL/6 J male mice were subcutaneously injected with monosodium glutamate (MSG) to induce obesity on a conventional diet. Six mice were also administered 5% FOS via drinking water from 10 weeks of age. At 18 weeks, histological characteristics of the liver and epididymal fat were compared between the groups. Hepatic mRNA expression of lipid metabolism enzymes and SCFA in feces and sera were measured. RESULTS: Hepatic steatosis, inflammatory cell infiltration, and hepatocyte ballooning in the liver and increased hepatic mRNA expression of fatty acid synthase and glycerol-3-phosphate acyltransferase were observed in the MSG-treated mice. FOS treatment improved the liver pathology and blunted the increases in the mRNA expression levels of lipid metabolism enzymes. In addition, FOS inhibited adipocyte enlargement and formation of crown-like structures and reduced the M1 macrophage frequency in the epididymal fat of the MSG mice (39.4% ± 3.0% vs. 22.8% ± 0.7%; P = 0.001). FOS increased not only the fecal concentrations of n-butyric acid (0.04 ± 0.01 vs. 0.38 ± 0.14 mg/g, P = 0.02), propionic acid (0.09 ± 0.03 vs. 0.42 ± 0.16 mg/g, P = 0.02), and acetic acid (0.65 ± 0.16 vs. 1.48 ± 0.29 mg/g, P = 0.03) but also the serum concentration of propionic acid (3.9 ± 0.5 vs. 8.2 ± 0.5 µmol/L, P = 0.001). CONCLUSIONS: FOS ameliorates steatohepatitis, visceral adiposity, and chronic inflammation by increasing SCFA production.

High-throughput sequencing of IgG B-cell receptors reveals frequent usage of the rearranged IGHV4-28/IGHJ4 gene in primary immune thrombocytopenia.

Primary immune thrombocytopenia (ITP) is an acquired form of thrombocytopenia caused by IgG anti-platelet autoantibodies and represents an organ-specific autoimmune disorder. Although the glycoprotein (GP)IIb/IIIa and GPIb/IX have been shown to be targets for autoantibodies, the antigen specificity of autoantibodies is not fully elucidated. To identify the characteristics of IgG B-cell receptor (BCR) repertoires in ITP, we took advantage of adaptor-ligation PCR and high-throughput DNA sequencing methods for analyzing the clone-based repertoires of IgG-expressing peripheral blood B cells. A total of 2,009,943 in-frame and 315,469 unique reads for IGH (immunoglobulin heavy) were obtained from twenty blood samples. Comparison of the IGHV repertoires between patients and controls revealed an increased usage of IGHV4-28 in ITP patients. One hundred eighty-six distinct IGHV4-28-carrying sequences were identified in ITP patients and the majority of these clones used an IGHJ4 segment. The IGHV4-28/IGHJ4-carrying B-cell clones were found in all ITP patients. Oligoclonal expansions of IGHV4-28/IGHJ4-carrying B cells were accompanied by multiple related clones with single amino substitution in the CDR3 region suggesting somatic hypermutation. Taken together, the expansion of IGHV4-28/IGHJ4-carrying IgG-expressing B cells in ITP may be the result of certain antigenic pressure and may provide a clue for the immune pathophysiology of ITP.

Umbilical catheterization training: Tissue hybrid versus synthetic trainer.

BACKGROUND: This study of umbilical catheterization deliberate practice training compared skill and knowledge outcomes of umbilical catheterization using a tissue-hybrid simulator (REAL) versus a synthetic simulated umbilical cord task trainer (ART). METHODS: This was a prospective randomized control study. Pediatric residents were randomized to REAL or ART umbilical catheterization deliberate practice training. Pre-post-training changes in skill performance and knowledge scores for REAL and ART groups were compared. Fidelity of REAL and ART were compared by neonatologists. RESULTS: Twenty-seven pediatric residents completed training. Post-training mean skill scores were improved compared to pre-test scores (REAL, P < 0.001; ART, P < 0.0001). Post-training skill, knowledge, and self-efficacy scores were not different between the REAL and ART groups. Fidelity of REAL was higher than ART for neonatologists (P < 0.01). CONCLUSIONS: The face validity of REAL was superior to ART, but resident umbilical cord deliberate practice training demonstrated no difference in skill, knowledge, and self-efficacy improvements between REAL and ART. Further studies on real patients are needed to evaluate the impact of using real or simulated umbilical cords for umbilical venous catheter/umbilical arterial catheter training.

Anti-drug Antibodies Against a Novel Humanized Anti-CD20 Antibody Impair Its Therapeutic Effect on Primary Biliary Cholangitis in Human CD20- and FcγR-Expressing Mice.

There is considerable interest in expanding B cell-targeted therapies in human autoimmune diseases. However, clinical trials in human primary biliary cholangitis (PBC) using a chimeric antibody against human CD20 (hCD20) have showed limited efficacy. Two potential explanations for these disappointing results are the appearance of anti-drug antibodies (ADAs) and the high frequency of patients with moderate PBC or patients who had failed ursodeoxycholic acid treatment. Here, we studied a novel humanized IgG1 antibody against hCD20 and explored its efficacy in early stage PBC using a well-defined murine model. We developed a unique murine model consisting of dnTGF-ßRII mice expressing hCD20 and human Fcγ receptors (hFcγRs). Beginning at 4-6 weeks of age, equivalent to stage I/II human PBC, female mice were given weekly injections of an anti-hCD20 antibody (TKM-011) or vehicle control, and monitored for liver histology as well as a broad panel of immunological readouts. After 16 weeks' treatment, we observed a significant reduction in portal inflammation, a decrease in liver-infiltrating mononuclear cells as well as a reduction in liver CD8+ T cells. Importantly, direct correlations between numbers of liver non-B cells and B cells (r = 0.7426, p = 0.0006) and between numbers of liver memory CD8+ T cells and B cells (r = 0.6423, p = 0.0054) were apparent. Accompanying these changes was a dramatic reduction in anti-mitochondrial antibodies (AMAs), interleukin (IL)-12p40 and IL-5, and elevated levels of the anti-inflammatory chemokine CXCL1/KC. In mice that developed ADAs, clinical improvements were less pronounced. Sustained treatment with B cell-targeted therapies may broadly inhibit effector pathways in PBC, but may need to be administered early in the natural history of PBC.

ICAM-1 upregulation is not required for retinoic acid-induced human eosinophil survival.

Active metabolites of vitamin A, retinoic acids (RAs), are known to play critical roles in mucosal immune responses and dramatically inhibit human eosinophil apoptosis, but the detailed mechanisms have not been elucidated. We previously screened for ICAM-1 (CD54) upregulation in RA-stimulated human eosinophils by gene microarray analysis. As ICAM-1 induction and activation were observed to have a role in maintenance of eosinophil survival, we tested the hypothesis that RAs prolong eosinophil survival through ICAM-1 outside-in signaling. Blood-derived isolated eosinophils cultured with 9-cis RA and all-trans RA showed significant upregulation of ICAM-1 mRNA and cell surface expression. TTNPB, a retinoic acid receptor agonist, also induced ICAM-1 expression, while HX630, a retinoid X receptor agonist, did not. Furthermore, an RAR antagonist, HX531, completely inhibited the effect of RAs. Upregulated ICAM-1 was associated with altered kinetics of Akt, ERK, and p38 MAP kinase phosphorylation through ICAM-1 cross-linking, but an ICAM-1-blocking antibody did not affect RA-mediated cell survival. These findings indicate that RAs induce functional ICAM-1 expression through RARs, but the induced ICAM-1 does not contribute to prolongation of eosinophil survival.

Fructo-oligosaccharides and intestinal barrier function in a methionine-choline-deficient mouse model of nonalcoholic steatohepatitis.

Impairments in intestinal barrier function, epithelial mucins, and tight junction proteins have been reported to be associated with nonalcoholic steatohepatitis. Prebiotic fructo-oligosaccharides restore balance in the gastrointestinal microbiome. This study was conducted to determine the effects of dietary fructo-oligosaccharides on intestinal barrier function and steatohepatitis in methionine-choline-deficient mice. Three groups of 12-week-old male C57BL/6J mice were studied for 3 weeks; specifically, mice were fed a methionine-choline-deficient diet, a methionine-choline-deficient diet plus 5% fructo-oligosaccharides in water, or a normal control diet. Fecal bacteria, short-chain fatty acids, and immunoglobulin A (IgA) levels were investigated. Histological and immunohistochemical examinations were performed using mice livers for CD14 and Toll-like receptor-4 (TLR4) expression and intestinal tissue samples for IgA and zonula occludens-1 expression in epithelial tight junctions. The methionine-choline-deficient mice administered 5% fructo-oligosaccharides maintained a normal gastrointestinal microbiome, whereas methionine-choline-deficient mice without prebiotic supplementation displayed increases in Clostridium cluster XI and subcluster XIVa populations and a reduction in Lactobacillales spp. counts. Methionine-choline-deficient mice given 5% fructo-oligosaccharides exhibited significantly decreased hepatic steatosis (p = 0.003), decreased liver inflammation (p = 0.005), a decreased proportion of CD14-positive Kupffer cells (p = 0.01), decreased expression of TLR4 (p = 0.04), and increases in fecal short-chain fatty acid and IgA concentrations (p < 0.04) compared with the findings in methionine-choline-deficient mice that were not administered this prebiotic. This study illustrated that in the methionine-choline-deficient mouse model, dietary fructo-oligosaccharides can restore normal gastrointestinal microflora and normal intestinal epithelial barrier function, and decrease steatohepatitis. The findings support the role of prebiotics, such as fructo-oligosaccharides, in maintaining a normal gastrointestinal microbiome; they also support the need for further studies on preventing or treating nonalcoholic steatohepatitis using dietary fructo-oligosaccharides.

The effect of hepatocyte growth factor on secretory functions in human eosinophils.

Hepatocyte growth factor (HGF), originally identified as a potent mitogen for mature hepatocytes, is now recognized as a humoral mediator in inflammatory and immune responses. Previous studies indicated that HGF negatively regulated allergic airway inflammation. In view of eosinophils playing a role in the pathogenesis of asthma, especially in airway remodeling as a rich source of pro-fibrogenic mediators, the effects of HGF on the different types of eosinophil secretory functions were examined in this study. We found that HGF significantly inhibited IL-5-induced secretion of TGF-ß and VEGF from human eosinophils. The inhibitory effect is not associated with TGF-ß transcription; rather, it is associated with ultrastructural granule emptying and loss of intracellular TGF-ß contents, indicating HGF inhibits the process of piecemeal degranulation. The effect of HGF on extracellular trap cell death (ETosis) that mediates cytolytic degranulation was also investigated; however, immobilized IgG- or phorbol myristate acetate-induced ETosis was only minimally attenuated by HGF. These results reveal the effect of HGF on the distinct pathways of eosinophil secretory functions and also provide novel insights into the role of HGF in the pathogenesis of allergic inflammation.

Correction: Functional Analysis of Free Fatty Acid Receptor GPR120 in Human Eosinophils: Implications in Metabolic Homeostasis.

[This corrects the article DOI: 10.1371/journal.pone.0120386.].

Eosinophil extracellular trap cell death-derived DNA traps: Their presence in secretions and functional attributes.

BACKGROUND: Activated human eosinophils, as well as neutrophils, can release extracellular chromatin to form DNA traps through cytolytic extracellular trap cell death (ETosis). Although formations of neutrophil DNA traps are recognized in patients with various inflammatory conditions, neither the presence of ETosis-derived eosinophil DNA traps in human allergic diseases nor the characteristics of these DNA traps have been studied. OBJECTIVE: We investigated the presence of ETosis-derived DNA traps in eosinophil-rich sinus and ear secretions and the functional attributes of ETosis DNA traps. METHODS: Eosinophil-rich secretions obtained from patients with eosinophilic chronic rhinosinusitis and eosinophilic otitis media were studied microscopically. In vitro studies of ETosis and DNA trap formation used blood-derived eosinophils and neutrophils, and studies of the binding capacities of DNA traps used labeled bacteria and fluorescent microbeads. Stabilities of DNA traps were evaluated by using fluorescence microscopy. RESULTS: Abundant nuclear histone H1-bearing DNA traps formed in vivo in the eosinophilic secretions and contributed to their increased viscosity. In vitro, after brief shear flow, eosinophil ETosis-elicited DNA traps assembled to form stable aggregates. Eosinophil DNA traps entrapped bacteria and fungi and, through hydrophobic interactions, microbeads. In comparison with neutrophil-derived DNA traps, eosinophil DNA traps ultrastructurally exhibited thicker fibers with globular structures and were less susceptible to leukocyte-derived proteolytic degradation, likely because of the lesser protease activities of eosinophils. CONCLUSIONS: In human allergic diseases local cytolysis of eosinophils not only releases free eosinophil granules but also generates nuclear-derived DNA traps that are major extracellular structural components within eosinophil-rich secretions.

Accumulated myeloid-derived suppressor cells demonstrate distinct phenotypes and functions in two non-alcoholic steatohepatitis mouse models.

BACKGROUND: To examine the steady state of hepatic myeloid-derived suppressor cells (MDSCs) and the lipid accumulation and inflammation-related changes in these cells, we analyzed the presence and functions of hepatic MDSCs in the following two non-alcoholic steatohepatitis (NASH) mouse models. METHODS: Monosodium glutamate (MSG) model; MSG was subcutaneously injected into neonatal male C57BL/6J mice that were fed with normal diet up to 18 weeks of age. Methionine/choline-deficient diet (MCD) model; 16-week-old male C57BL/6J mice were fed with an MCD for 2 weeks. Those hepatic MDSCs were evaluated by flow cytometry and immunohistochemically. RESULTS: Both MSG and MCD mice exhibited greater numbers of hepatic lipid droplets than 18-week-old male control mice. Hepatocellular ballooning was obvious in MSG, whereas inflammatory cell infiltration were apparent in MCD mice. CD11b, CD115, and Gr-1-positive hepatic MDSCs were increased in both models but higher in MCD mice, and demonstrated higher expression of an M2 macrophage marker CD206 mean fluorescence intensity (MFI) in MSG compared to MCD mice. Degree of reactive oxygen species production was evaluated using the DCFDA MFI values, which were significantly elevated in hepatic MDSCs from MCD mice. MSG mouse livers demonstrated Gr-1 positive cell accumulation around lipid droplets, mimicking crown-like structures in adipose tissues. In contrast, hepatic Gr-1 positive cells were primarily located in inflammatory cell aggregates in MCD mice. CONCLUSIONS: These results suggest that hepatic fatty changes promote MDSC accumulation, and inflammatory changes induce phenotypic and functional alteration in hepatic MDSCs in NASH mouse models.