RAB25 coordinates filaggrin-containing keratohyalin granule maturation and affects atopic dermatitis severity.

BACKGROUND: Keratohyalin granules (KHGs) supply the critical epidermal protein constituents such as filaggrin for maintaining skin barrier function during epidermal differentiation; however, their regulating mechanism remains largely unelucidated. METHODS: To investigate the role of Ras-related protein Rab-25 (RAB25) expression in skin disease, we utilized skin specimens of patients with moderate-to-severe atopic dermatitis (AD) and healthy controls. To investigate the susceptibility of Rab25 knockout mice to AD, we established an oxazolone-induced AD model. RESULTS: We investigated the role of RAB25 in KHG maturation and AD. RAB25-deficient mice showed a disrupted stratum corneum along with skin barrier dysfunction, decreased KHG production, and abnormal KHG processing. Consistently, in the human keratinocyte cell line HaCaT, RAB25 co-expressed with filaggrin-containing KHG and RAB25 silencing impaired KHG formation, which was attributable to abnormal actin dynamics. Most importantly, RAB25 expression was severely downregulated in the skin lesions of patients with AD, which was strongly correlated with disease severity scores. CONCLUSIONS: RAB25 coordinates KHG homeostasis by regulating actin dynamics and is critical for epidermal differentiation and the pathophysiology of AD.

Human gastric microbiota transplantation recapitulates premalignant lesions in germ-free mice.

OBJECTIVE: Gastric cancer (GC) is a leading cause of cancer-related mortality. Although microbes besides Helicobacter pylori may also contribute to gastric carcinogenesis, wild-type germ-free (GF) mouse models investigating the role of human gastric microbiota in the process are not yet available. We aimed to evaluate the histopathological features of GF mouse stomachs transplanted with gastric microbiota from patients with different gastric disease states and their relationships with the microbiota. DESIGN: Microbiota profiles in corpus and antrum tissues and gastric fluid from 12 patients with gastric dysplasia or GC were analysed. Thereafter, biopsied corpus and antrum tissues and gastric fluid from patients (n=15 and n=12, respectively) with chronic superficial gastritis, intestinal metaplasia or GC were inoculated into 42 GF C57BL/6 mice. The gastric microbiota was analysed by amplicon sequencing. Histopathological features of mouse stomachs were analysed immunohistochemically at 1 month after inoculation. An independent set of an additional 15 GF mice was also analysed at 1 year. RESULTS: The microbial community structures of patients with dysplasia or GC in the corpus and antrum were similar. The gastric microbiota from patients with intestinal metaplasia or GC selectively colonised the mouse stomachs and induced premalignant lesions: loss of parietal cells and increases in inflammation foci, in F4/80 and Ki-67 expression, and in CD44v9/GSII lectin expression. Marked dysplastic changes were noted at 1 year post inoculation. CONCLUSION: Major histopathological features of premalignant changes are reproducible in GF mice transplanted with gastric microbiota from patients with intestinal metaplasia or GC. Our results suggest that GF mice are useful for analysing the causality of associations reported in human gastric microbiome studies.

WFDC2 Promotes Spasmolytic Polypeptide-Expressing Metaplasia Through the Up-Regulation of IL33 in Response to Injury.

BACKGROUND & AIMS: WAP 4-disulfide core domain protein 2 (WFDC2), also known as human epididymis protein 4, is a small secretory protein that is highly expressed in fibrosis and human cancers, particularly in the ovaries, lungs, and stomach. However, the role of WFDC2 in carcinogenesis is not fully understood. The present study aimed to investigate the role of WFDC2 in gastric carcinogenesis with the use of preneoplastic metaplasia models. METHODS: Three spasmolytic polypeptide-expressing metaplasia (SPEM) models were established in both wild-type and Wfdc2-knockout mice with DMP-777, L635, and high-dose tamoxifen, respectively. To reveal the functional role of WFDC2, we performed transcriptomic analysis with DMP-777-treated gastric corpus specimens. RESULTS: Wfdc2-knockout mice exhibited remarkable resistance against oxyntic atrophy, SPEM emergence, and accumulation of M2-type macrophages in all 3 SPEM models. Transcriptomic analysis revealed that Wfdc2-knockout prevented the up-regulation of interleukin-33 (IL33) expression in the injured mucosal region of SPEM models. Notably, supplementation of recombinant WFDC2 induced IL33 production and M2 macrophage polarization, and ultimately promoted SPEM development. Moreover, long-term treatment with recombinant WFDC2 was able to induce SPEM development. CONCLUSIONS: WFDC2 expressed in response to gastric injury promotes SPEM through the up-regulation of IL33 expression. These findings provide novel insights into the role of WFDC2 in gastric carcinogenesis.

A Life-Threatening Infection after Endobronchial Ultrasound Transbronchial Lung Biopsy with Guide Sheath: A Case Report.

BACKGROUND AND OBJECTIVES: Endobronchial ultrasound transbronchial lung biopsy with guide sheath (EBUS-GS-TBLB) has been regarded as a reasonable diagnostic method with an acceptable diagnostic yield. In addition, EBUS-GS-TBLB is considered safer and less invasive compared to percutaneous needle biopsy and thoracoscopic surgery. However, we encountered a case of life-threatening procedure-related fatal infection, which was successfully managed. CASE PRESENTATION: A 61-year-old man with a 30 pack-year smoking history was referred to our clinic with a necrotic lung mass in the right middle lobe on a chest computed tomography scan. EBUS-GS-TBLB was performed for a pathological diagnosis without immediate complications. Eight days after the procedure, the patient visited the hospital with sudden hemoptysis and severe dyspnea with fever. A chest computed tomography revealed a ruptured lung abscess and pneumonia, developed after EBUS-GS-TBLB. Extracorporeal membrane oxygenation (ECMO) and mechanical ventilation were initiated to manage refractory hypoxia. While maintaining ECMO, video-assisted thoracoscopic surgery was performed at the patient's bedside in the intensive care unit. After surgery, the patient's vital signs gradually improved, and a chest computed tomography revealed a reduction in the extent of the lung abscess. RESULTS: Although EBUS-GS-TBLB is minimally invasive and relatively safe when used for the diagnosis of peripheral lung lesions, pulmonary physicians should be aware of this rare but critical complication. CONCLUSIONS: We suggest that the careful prescription of prophylactic antibiotics before EBUS-GS-TBLB would be wise if the mass featured a necrotic, cavitary, or cystic lesion.

Co-Culturing of Endothelial and Cancer Cells in a Nanofibrous Scaffold-Based Two-Layer System.

Angiogenesis is critical for local tumor growth. This study aimed to develop a three-dimensional two-layer co-culture system to investigate effects of cancer cells on the growth of endothelial cells (ECs). Poly(ε-caprolactone) (PCL) nanofibrous membranes were generated via electrospinning of PCL in chloroform (C-PCL-M) and chloroform and dimethylformamide (C/DMF-PCL-M). We assembled a two-layer co-culture system using C-PCL-M and C/DMF-PCL-M for EC growth in the upper layer with co-cultured cancer cells in the lower layer. In the absence of vascular endothelial growth factor (VEGF), growth of bEND.3 ECs decreased on C/DMF-PCL-M but not on C-PCL-M with time. Growth of bEND.3 cells on C/DMF-PCL-M was enhanced through co-culturing of CT26 cancer cells and enhanced growth of bEND.3 cells was abrogated with anti-VEGF antibodies and sorafenib. However, EA.hy926 ECs displayed steady growth and proliferation on C/DMF-PCL-M, and their growth was not further increased through co-culturing of cancer cells. Moreover, chemical hypoxia in CT26 cancer cells upon treatment with CoCl2 enhanced the growth of co-cultured bEND.3 cells in the two-layer system. Thus, EC growth on the nanofibrous scaffold is dependent on the types of ECs and composition of nanofibers and this co-culture system can be used to analyze EC growth induced by cancer cells.

Histamine Signaling Is Essential for Tissue Macrophage Differentiation and Suppression of Bacterial Overgrowth in the Stomach.

BACKGROUND & AIMS: Histamine in the stomach traditionally is considered to regulate acid secretion but also has been reported to participate in macrophage differentiation, which plays an important role in tissue homeostasis. Therefore, this study aimed to uncover the precise role of histamine in mediating macrophage differentiation and in maintaining stomach homeostasis. METHODS: Here, we expand on this role using histidine decarboxylase knockout (Hdc-/-) mice with hypertrophic gastropathy. In-depth in vivo studies were performed in Hdc-/- mice, germ-free Hdc-/- mice, and bone-marrow-transplanted Hdc-/- mice. The stomach macrophage populations and function were characterized by flow cytometry. To identify stomach macrophages and find the new macrophage population, we performed single-cell RNA sequencing analysis on Hdc+/+ and Hdc-/- stomach tissues. RESULTS: Single-cell RNA sequencing and flow cytometry of the stomach cells of Hdc-/- mice showed alterations in the ratios of 3 distinct tissue macrophage populations (F4/80+Il1bhigh, F4/80+CD93+, and F4/80-MHC class IIhighCD74high). Tissue macrophages of the stomachs of Hdc-/- mice showed impaired phagocytic activity, increasing the bacterial burden of the stomach and attenuating hypertrophic gastropathy in germ-free Hdc-/- mice. The transplantation of bone marrow cells of Hdc+/+ mice to Hdc-/- mice recovered the normal differentiation of stomach macrophages and relieved the hypertrophic gastropathy of Hdc-/- mice. CONCLUSIONS: This study showed the importance of histamine signaling in tissue macrophage differentiation and maintenance of gastric homeostasis through the suppression of bacterial overgrowth in the stomach.

Gut microbiota of the young ameliorates physical fitness of the aged in mice.

BACKGROUND: Aging is a natural process that an organism gradually loses its physical fitness and functionality. Great efforts have been made to understand and intervene in this deteriorating process. The gut microbiota affects host physiology, and dysbiosis of the microbial community often underlies the pathogenesis of host disorders. The commensal microbiota also changes with aging; however, the interplay between the microbiota and host aging remains largely unexplored. Here, we systematically examined the ameliorating effects of the gut microbiota derived from the young on the physiology and phenotypes of the aged. RESULTS: As the fecal microbiota was transplanted from young mice at 5 weeks after birth into 12-month-old ones, the thickness of the muscle fiber and grip strength were increased, and the water retention ability of the skin was enhanced with thickened stratum corneum. Muscle thickness was also marginally increased in 25-month-old mice after transferring the gut microbiota from the young. Bacteria enriched in 12-month-old mice that received the young-derived microbiota significantly correlated with the improved host fitness and altered gene expression. In the dermis of these mice, transcription of Dbn1 was most upregulated and DBN1-expressing cells increased twice. Dbn1-heterozygous mice exhibited impaired skin barrier function and hydration. CONCLUSIONS: We revealed that the young-derived gut microbiota rejuvenates the physical fitness of the aged by altering the microbial composition of the gut and gene expression in muscle and skin. Dbn1, for the first time, was found to be induced by the young microbiota and to modulate skin hydration. Our results provide solid evidence that the gut microbiota from the young improves the vitality of the aged. Video Abstract.

Development of a prognostic scoring system in patients with pneumonia requiring ventilator care for more than 4 days: a single-center observational study.

BACKGROUND: The aim of the present study was to develop a prognostic model using demographic characteristics, comorbidities, and clinical variables measured on day 4 of mechanical ventilation (MV) for patients with prolonged acute mechanical ventilation (PAMV; MV for >96 hours). METHODS: Data from 437 patients (70.9% male; median age, 68 years) were obtained over a period of 9 years. All patients were diagnosed with pneumonia. Binary logistic regression identified factors predicting mortality at 90 days after the start of MV. A PAMV prognosis score was calculating ß-coefficient values and assigning points to variables. RESULTS: The overall 90-day mortality rate was 47.1%. Five factors (age ≥65 years, body mass index <18.5 kg/m2, hemato-oncologic diseases as comorbidities, requirement for vasopressors on day 4 of MV and requirement for neuromuscular blocking agents on day 4 of MV) were identified as prognostic indicators. Each factor was valued as +1 point, and used to develop a PAMV prognosis score. This score showed acceptable discrimination (area under the receiver operating characteristic curve of 0.695 for mortality, 95% confidence interval 0.650-0.738, p<0.001), and calibration (Hosmer-Lemeshow chi-square=6.331, with df 7 and p=0.502). The cutoff value for predicting mortality based on the maximum Youden index was ≤2 (sensitivity, 87.5%; specificity, 41.3%). For patients with PAMV scores ≤1, 2, 3 and ≥4, the 90-day mortality rates were 29.2%, 45.7%, 67.9%, and 90.9%, respectively (P<0.001). CONCLUSIONS: Our study developed a PAMV prognosis score for predicting 90-day mortality. Further research is needed to validate the utility of this score.

Linezolid-induced black hairy tongue in a patient with multidrug-resistant tuberculosis: A case report.

The revised World Health Organization guidelines on multidrug-resistant tuberculosis include linezolid in the core drugs group. Consequently, the use of linezolid for patients with multidrug-resistant tuberculosis is increasing. Common adverse events of long-term linezolid use include bone marrow suppression and neuropathies. However, there is limited information on a rare adverse event, black hairy tongue. Here, we report a case of linezolid-induced black hairy tongue in a patient with multidrug-resistant tuberculosis. The etiology, pathogenesis, diagnosis, and treatment of black hairy tongue are also discussed.

Sequential Organ Failure Assessment score as a predictor of mortality in ventilated patients with multidrug-resistant bacteremia.

BACKGROUND: The occurrence of multidrug-resistant (MDR) bacteremia in ventilated patients may be associated with a high mortality rate. We evaluated whether Sequential Organ Failure Assessment (SOFA) score on the day of bacteremia could predict 90-day mortality in these patients. METHODS: Data were obtained retrospectively from 202 patients (male, 60.4%; median age, 64 years) hospitalized at a single university-affiliated tertiary care hospital. All adult patients who had were ventilated and had one of the following six MDR bacteremias between March 2011 and February 2018 were enrolled: methicillin-resistant Staphylococcus aureus, extended-spectrum ß-lactamase-producing Gram-negative bacteria (Escherichia coli and Klebsiella pneumonia), carbapenem-resistant Gram-negative rods (Acinetobacter baumannii and Pseudomonas aeruginosa), or vancomycin-resistant Enterococcus faecium. RESULTS: The overall 90-day mortality rate after the day of bacteremia was 59.9%. The areas under the receiver operating characteristic curves for the SOFA and Acute Physiology and Chronic Health Evaluation (APACHE) II scores were 0.732 (95% confidence interval [CI], 0.666 to 0.792; P<0.001) and 0.662 (95% CI, 0.593 to 0.727; P<0.001), respectively, with no difference between the two (P=0.059). Also, the cutoff value of the SOFA score was 9 (based on Youden's index). Multivariate Cox regression analysis showed that this cut-off value was significantly associated with higher mortality rate (hazard ratio, 2.886; 95% CI, 1.946 to 4.221; P<0.001). CONCLUSIONS: SOFA score measured on the day of bacteremia may be a useful prognostic indicator of 90-day mortality in ventilated patients with MDR bacteremia.