Subepithelial Collagen Deposition Research Articles

Heat-killed Akkermansia muciniphila ameliorates allergic airway inflammation in mice.

Allergic asthma (AA) is a common inflammatory airway disease characterized by increased airway hyper-responsiveness (AHR), inflammation, and remodeling. Akkermansia muciniphila is a strictly anaerobic bacterium residing in the gut and is a promising next-generation probiotic to improve metabolic inflammatory syndrome. A recent study suggested the beneficial effect of live A. muciniphila on allergic airway inflammation (AAI) in mice. However, whether the heat-killed form can improve AAI requires further investigation. Mice sensitized and challenged with house dust mites (HDM) develop AA hallmarks including inflammatory cell infiltration, goblet cell hyperplasia, and subepithelial collagen deposition in the lungs. These phenomena were reversed by oral administration of the heat-killed A. muciniphila strain EB-AMDK19 (AMDK19-HK) isolated from the feces of healthy Koreans. Furthermore, AMDK19-HK diminished the HDM-induced AHR to inhaled methacholine, lung mast cell accumulation, and serum HDM-specific IgE levels. It also led to the overall suppression of IL-4, IL-13, and eotaxin production in bronchoalveolar lavage fluids, and Il4, Il5, Il13, and Ccl17 gene expression in lung tissues. Moreover, AMDK19-HK suppressed Th2-associated cytokine production in the splenocytes of HDM-sensitized mice in vitro. Additionally, a combination of 16S rRNA gene sequencing and short-chain fatty acid (SCFA) analysis in cecal samples revealed that AMDK19-HK modulated the relative abundance of circulating SCFA-associated gut genera, including a positive correlation with Lachnospiraceae_ NK4A136_group and a negative correlation with Lachnoclostridium and significantly increased cecal SCFA concentrations. Finally, AMDK19-HK improved intestinal mucosal barrier function. These results suggest that the oral administration of AMDK19-HK ameliorates HDM-induced AAI in mice by suppressing Th2-mediated immune responses and could have a protective effect against AA development.

Blockade of MIF biological activity ameliorates house dust mite-induced allergic airway inflammation in humanized MIF mice.

Macrophage migration inhibitory factor (MIF) expression is controlled by a functional promoter polymorphism, where the number of tetranucleotide repeats (CATTn ) corresponds to the level of MIF expression. To examine the role of this polymorphism in a pre-clinical model of allergic asthma, novel humanized MIF mice with increasing CATT repeats (CATT5 and CATT7 ) were used to generate a physiologically relevant scale of airway inflammation following house dust mite (HDM) challenge. CATT7 mice expressing high levels of human MIF developed an aggressive asthma phenotype following HDM challenge with significantly elevated levels of immune cell infiltration, production of inflammatory mediators, goblet cell hyperplasia, subepithelial collagen deposition, and airway resistance compared to wild-type controls. Importantly the potent MIF inhibitor SCD-19 significantly mitigated the pathophysiology observed in CATT7 mice after HDM challenge, demonstrating the fundamental role of endogenous human MIF expression in the severity of airway inflammation in vivo. Up to now, there are limited reproducible in vivo models of asthma airway remodeling. Current asthma medications are focused on reducing the acute inflammatory response but have limited effects on airway remodeling. Here, we present a reproducible pre-clinical model that capitulates asthma airway remodeling and suggests that in addition to having pro-inflammatory effects MIF may play a role in driving airway remodeling.

Collagenous Gastritis Is an Underdiagnosed Cause of Anemia and Abdominal Pain: Systematic Scoping Review.

Collagenous gastritis (CG) is a rare disease characterized by infiltration of the lamina propria with mononuclear cells and subepithelial deposition of collagen. Due to its nonspecific presentation, it is often misdiagnosed. The clinical characteristics, endoscopic, and histopathologic features, and treatment outcomes of CG have not been well defined. We aim to summarize the existing evidence of CG. According to the PRISMA Extension for Scoping Reviews, we performed a search on MEDLINE and EMBASE for articles with keywords including "collagenous gastritis" and "microscopic gastritis" from the inception of these databases to August 20, 2022. 76 Articles, including nine observational studies, and 67 case reports and series were included. There were 86 cases of collagenous colitis in the final analysis. Most patients presented with anemia (61.4%), followed by abdominal discomfort (60.5%), diarrhea (25.3%), and nausea/vomiting (23.0%). While 60.2% had gastric nodularity on endoscopy, erythema or erosions (26.1%) were also common, as well as normal findings (12.5%). 65.9% of histopathologic findings included subepithelial collagen bands, and 37.5% had mucosal inflammatory infiltrates. Common treatments employed were iron supplementation (42%), followed by PPI (30.7%), prednisone (9.1%), and budesonide (6.8%). Clinical improvement was seen in 64.2%. This systematic review summarizes the clinical characteristics of CG. Further studies to establish clear diagnostic criteria and identify effective treatment modalities of this less-recognized entity are needed.

A235 “WHAT’S SPRUE WITH YOU?”: OLMESARTAN-INDUCED ENTEROPATHY AS AN UNCOMMON MIMICKER OF CELIAC DISEASE

Abstract Background Olmesartan-induced enteropathy is an uncommon mimicker of celiac disease. Symptoms include diarrhea and weight loss and pathology shows villous atrophy, intraepithelial lymphocytes, and subepithelial collagen deposition. In contrast to celiac disease, tissue transglutaminase (TTG) is not elevated and gluten avoidance does not induce clinical or histologic improvement. Both clinical and histologic findings are reversible with cessation of pharmacologic therapy. Purpose To raise clinician awareness of an uncommon but reversible cause of enteropathy. Method A 67-year old man presented with 3 months of progressive diarrhea and 35lb weight loss on a background of hypertension, dyslipidemia, and type 2 diabetes. His medications included olmesartan, amlodipine, metformin, aspirin, and atorvastatin, none of which were new. Infectious stool studies, serum and fecal inflammatory markers, imaging, TTG and IgA were normal. Panendoscopy revealed duodenitis with biopsies consistent with active enteritis, intraepithelial lymphocytosis and villous shortening suggestive of olmesartan-induced enteropathy given negative TTG. Olmesartan was discontinued. Result(s) His symptoms completely resolved over several weeks after discontinuation. Conclusion(s) Olmesartan is an uncommon but reversible mimicker of celiac disease. It was first described in 2012 in a case series of 22 patients, all of whom had negative celiac serology and demonstrated histologic and clinical improvement with cessation of olmesartan. Time from medication initiation to onset of symptoms ranged from 6 months to 7 years, with a mean of 3.1 years. While case reports exist of angiotensin-receptor blockers as causative agents, the most common is olmesartan, implicated in 94% of ARB-induced enteropathy cases in a recent systematic review. The exact mechanism of injury is unknown. The delay in onset of symptoms suggests a cell-mediated immunity phenomenon. An immune-mediated reaction is also supported by the high prevalence of HLA-DQ2/DQ8 haplotypes (71%) among affected individuals vs. 30-40% in the general population. Olmesartan may be implicated more strongly than other ARBs due to its higher affinity for AT1 receptors; theoretically leaving unsaturated AT2 receptors to bind angiotensin. AT2 receptors are known to induce cellular apoptosis, and unopposed cellular death could theoretically lead to villous atrophy. The overall risk of developing enteropathy on olmesartan is rare, but not well quantified. This is likely due to both underrecognition, and variability in study designs leading to inability to perform meta-analysis on currently available data. Data from a French cohort estimates a crude incidence rate of 5.6 per 100,000 person years for patients on olmesartan developing intestinal malabsorption requiring hospitalization. Despite its rarity, prescribers should be cognizant of this side effect which can evolve even after years of medical therapy. Please acknowledge all funding agencies by checking the applicable boxes below None Disclosure of Interest None Declared

House Dust Mite and Cat Dander Extract Induce Asthma-Like Histopathology with an Increase of Mucosal Mast Cells in a Guinea Pig Model.

Asthma is a chronic inflammatory disease with structural changes in the lungs defined as airway remodelling. Mast cell responses are important in asthma as they, upon activation, release mediators inducing bronchoconstriction, inflammatory cell recruitment, and often remodelling of the airways. As guinea pigs exhibit anatomical, physiological, and pharmacological features resembling human airways, including mast cell distribution and mediator release, we evaluated the effect of extracts from two common allergens, house dust mite (HDM) and cat dander (CDE), on histopathological changes and the composition of tryptase- and chymase-positive mast cells in the guinea pig lungs. Guinea pigs were exposed intranasally to HDM or CDE for 4, 8, and 12 weeks, and airway histology was examined at each time point. Hematoxylin and eosin, Picro-Sirius Red, and Periodic Acid-Schiff staining were performed to evaluate airway inflammation, collagen deposition, and mucus-producing cells. In addition, Astra blue and immunostaining against tryptase and chymase were used to visualize mast cells. Repetitive administration of HDM or CDE led to the accumulation of inflammatory cells into the proximal and distal airways as well as increased airway smooth muscle mass. HDM exposure caused subepithelial collagen deposition and mucus cell hyperplasia at all three time points, whereas CDE exposure only caused these effects at 8 and 12 weeks. Both HDM and CDE induced a substantial increase in mast cells after 8 and 12 weeks of challenges. This increase was primarily due to mast cells expressing tryptase, but not chymase, thus indicating mucosal mast cells. We here show that exposure to HDM and CDE elicits asthma-like histopathology in guinea pigs with infiltration of inflammatory cells, airway remodelling, and accumulation of primarily mucosal mast cells. The results together encourage the use of HDM and CDE allergens for the stimulation of a clinically relevant asthma model in guinea pigs.

Sini Decoction inhibits TLR4/NF-κB signaling pathway to improve airway remodeling of allergic asthmatic mice

This study aims to explore the effect of Sini Decoction on Toll-like receptor 4(TLR4)/nuclear factor-κB(NF-κB) signaling pathway in the mice with allergic asthma(AA). Forty-eight SPF-grade BALB/c mice were randomly assigned into a blank control group, a model group, a dexamethasone group, and high-, medium-, and low-dose Sini Decoction groups, with 8 mice in each group. The sensitization solution made of ovalbumin and aluminum hydroxide powder was injected intraperitoneally in other groups except the blank control group which was injected with an equal volume of normal saline. The solution(or normal saline) was injected three times in total with an interval of 7 days. At the same time of sensitization, external cold stimulation and ice water were administered in a 4 ℃ climate box for 20 min every day. After modeling, the mice in each group were administrated with corresponding drugs by gavage for 3 weeks. At the end of administration, pentobarbital sodium(30 mg·kg~(-1)) was used for anesthesia, and then the samples were collected for the determination of various indexes. The phenol red test was conducted to evaluate tracheal excretion function. The histopathological changes of lung tissue were observed via hematoxylin-eosin(HE) staining. Masson staining was employed to reveal the deposition of blue collagen fibers around bronchi in lung tissue and the area occupied by blue collagen fibers was calculated. Immunofluorescence method was used to measure the expression of bronchial type Ⅰ collagen(Col-Ⅰ) and α-smooth muscle actin(α-SMA). The protein and mRNA levels of TLR4, NF-κB, cysteinyl aspartate specific proteinase-1(caspase-1), and interleukin-13(IL-13) were determined by Western blot and real-time fluorescence quantitative polymerase chain reaction(real-time PCR), respectively. Compared with the model group, Sini Decoction significantly increased the phenol red excretion from trachea, lowered the lung inflammation score, reduced subepithelial collagen deposition, and decreased Col-Ⅰ and α-SMA levels. Furthermore, the decoction down-regulated the protein and mRNA levels of TLR4, NF-κB, caspase-1, and IL-13 in mouse lung tissue. In conclusion, Sini Decoction can improve air remodeling by inhibiting the TLR4/NF-κB signaling pathway.

S3677 Tissue Is the Issue: A Rare Case of Collagenous Gastritis

Introduction: Collagenous gastritis (CG), collagenous sprue, and collagenous colitis are rare forms of collagenous gastroenteritides marked by subepithelial collagen deposition of more than 10 mm and inflammatory infiltrate in the lamina propria. CG was first identified in 1989. It's a rare disease, with just 100 cases reported so far. Here, we present a distinct case of collagenous gastritis. Case Description/Methods: 52-year-old female with no chronic medical conditions presented with symptoms of mild reflux, epigastric pain, and intermittent diarrhea up to 5 times per day. She had sporadic Ibuprofen use for headaches. Her mother was diagnosed with lupus and a half-sister with a history of mixed connective tissue disorder. Initial upper endoscopy revealed grade B esophagitis and gastritis, biopsies showed CG. Colonoscopy with random biopsies showed no evidence of collagenous colitis. She was treated with high dose proton pump inhibitor (PPI) and repeat endoscopy in 4 weeks with biopsies via Sydney protocol was performed. Additional blood work was normal including normal thyroid panel, celiac screen (anti-transglutaminase IgA: < 1.0 U/ml, IgA: 2.34 g/L) and IgG4 titer (0.27 g/L.) Repeat EGD with biopsies per Sydney protocol confirmed CG in all gastric quadrants, except fundus. After stopping NSAIDs and continuing on PPI, her symptoms resolved with a plan for surveillance endoscopy in 6 months (Figure 1). Discussion: In our patient, the diagnosis of CG led to further investigations to rule out possible associated autoimmune diseases. The occasional ibuprofen may have been contributory, but the repeat biopsies on the second endoscopy confirmed the presence of CG despite cessation. The only contributing factor in her case is positive family history. There are very few cases reported in the literature with the possible association of lupus with CG. This distinctive case of CG is an important contribution to the limited pool of existing cases as the patient herself did not have any preexisting allergic or autoimmune conditions and it appears that this process occurred idiopathically. Given the rarity of the condition and limited literature available, we emphasize the importance of delineated medical guidelines for appropriate screening and surveillance.Figure 1.: Endoscopic appearance of collagenous gastritis. A, B. body, C. Antrum D. fundus ; E, F: Histology of collagenous gastritis characterized by thickening of sub epithelial basement membrane accompanied by diffuse superficial lymphoplasmacytic infiltrates and surface epithelial degeneration. Table 1. - Summary of Collagenous gastritis (CG) COLLAGENOUS GASTRITIS (CG) - Characterized by marked sub epithelial collagen deposition with associated inflammatory infiltrate. EPIDEMIOLOGY - Female Preponderance - All age groups but primarily affects adults. ETIOLOGY - The etiology is unknown - Stancu et al. outlined three pathogenic mechanisms that may lead to collagen deposition in cases of CG: (1) Chronic inflammation (2) Fibroblast sheath abnormality (3) Leakage of plasma proteins and fibrinogen ASSOCIATIONS - Intestinal and autoimmune disorders, including celiac disease. collagenous enteritis, collagenous colitis, sjogren syndrome, SLE, juvenile arthritis, RA, Hashimoto's thyroiditis, Grave's disease, Diabetes mellitus type 1, and CVID. - Medications such as Olmesartan, Venlafaxine SYMPTOMS AND SIGNS - Epigastric and or abdominal pain, anemia , gastrointestinal bleeding, diarrhea, nausea and vomiting, perforated ulcer, weight loss, abdominal distension, fatigue, dyspepsia, retrosternal pain, constipation and dysphagia. DIAGNOSIS - EGD with biopsy TREATMENT - Anti-secretory agents including PPIs, and H2 receptor antagonists, steroids, iron supplementation and hypoallergenic diets have been tried with limited success. - Other treatment modalities , such as sucralfate, mesalazine, bismuth subsalicylate, furazolidone, sulfasalazine, azathioprine, and parenteral nutrition have also been tested.

S3695 Collagenous Gastritis: A Rare Cause of Severe Iron Deficiency Anemia in a Basic Military Trainee

Introduction: Collagenous gastritis is a rare inflammatory disease characterized by deposition of a thick subepithelial band of collagen and associated inflammatory infiltrate. This disorder has a reported prevalence of 13 per 100,000 esophagogastroduodenoscopies (EGDs) with a female predominance. Two distinct clinical phenotypes have been described: adult-onset characterized by diffuse gastrointestinal involvement and diarrhea, and pediatric-onset manifesting with abdominal pain and anemia. We present an interesting case of pediatric-phenotype collagenous gastritis to highlight this poorly-recognized disorder. Case Description/Methods: A 19-year-old male basic military trainee was referred for evaluation of incidentally discovered iron deficiency anemia. He denied any symptoms, overt blood loss, or NSAIDs. Physical exam was unremarkable. Labs revealed hemoglobin of 9.3 g/dL, iron saturation 7% and ferritin 15 ng/mL. The patient underwent EGD and colonoscopy for further evaluation. EGD revealed a diffusely nodular appearance of the gastric mucosa with areas with suspected atrophy under narrow-band imaging (Figures 1A, B). Colonoscopy was normal. Biopsies returned with a non-specific chronic gastritis without H. pylori. Abdominal computed tomography and additional work up for autoimmune gastritis, fecal H. pylori antigen, syphilis, and heavy metals toxins were all normal. Decision was made to repeat EGD for additional tissue sampling, including cold snared samples. Repeat gastric biopsies with expert GI pathologist review revealed collagenous gastritis, characterized by subepithelial deposition of a thick (greater than 10 µm) collagen band and associated inflammatory infiltrate (Figures 1C, D). Patient was lost to follow up due to disqualification for military service. Discussion: Collagenous gastritis is an exceedingly rare heterogeneous disease process of poorly understood causes and pathogenesis, with autoimmune conditions, medication effects, and infections theorized to be responsible. Numerous treatments have been reported with variable effect, including antisecretory agents, corticosteroids, immunomodulators, and hypoallergenic diets, along with micronutrient supplementation. Due to its rarity, a high level of suspicion is required by gastroenterologists and pathologists based on clinical and endoscopic findings. Our case helps to bring awareness to collagenous gastritis, and emphasizes the potential value for repeat tissue sampling with expert pathologist review.Figure 1.: A: Diffusely nodular appearance of the gastric mucosa with areas. B: Narrow-band imaging reveals areas of suspected atrophy. C: Multiple fragments of gastric mucosa with a prominent lymphoplasmacytic infiltrate within the lamina propria and occasional foci of subepithelial collagen deposition (red arrows). [Hematoxylin & Eosin, 50× magnification]. D: On higher magnification a focus of subepithelial collagen deposition may be seen associated with epithelial injury indicated by loss of foveolar mucin and detachment of the surface epithelium. [Hematoxylin & Eosin, 200× magnification].

An Inhibitor of Nuclear Factor-Kappa B Pathway Attenuates the Release of TGF-β1 and Inhibits the Fibrogenic Progress in a Model of Airway Remodeling Induced by Acrolein.

Airway inflammation, airway hypersecretion, and airway remodeling are believed to be involved in the process of lung fibrosis. Nowadays, acrolein is widely used to establish the model of airway remodeling. An active component of propolis, named caffeic acid phenethyl ester (CAPE), is recognized as an inhibitor of the NF-κB pathway and shows anti-inflammatory effect. The purpose of this study was to investigate the protective effect of CAPE on acrolein-induced airway remodeling. 24 mice were divided into 4 groups: control group; acrolein group, mice received acrolein (inhalation of acrolein for 20 days); CAPE group, mice received CAPE (30 mg/kg); and acrolein+CAPE group, mice received acrolein and CAPE. After 20 days, lung tissue was removed for histopathology and immunohistochemical evaluations. TGF-β1 and Muc5ac levels were measured at the protein and molecular levels. Additionally, the phospho-P65/P65 values in the airway smooth muscle cells treated with TGF-β1 or CAPE were detected by Western blot. The results showed that compared with the control, subepithelial collagen deposition, airway inflammation, and peribronchus fibrosis were inhibited in the group treated with CAPE. Furthermore, TGF-β1 was significantly decreased in the acrolein+CAPE group compared with the acrolein group. Additionally, we identified CAPE inhibited P65 phosphorylation. However, CAPE did not inhibit the Muc5ac overproduction and hypersecretion induced by acrolein. In conclusion, as an inhibitor of the NF-κB pathway, CAPE attenuated the release of TGF-β1, which inhibited the fibrogenic progress induced by acrolein in mice and took no effect on inhibiting airway mucus hypersecretion.

CTLA4-Ig mediated immunosuppression favors immunotolerance and restores graft in mouse airway transplants

CTLA4-Ig is a potent costimulatory blocker that inhibits T cell activation during alloimmune inflammation and increases graft survival and function. CTLA4-Ig-mediated immunosuppression has been demonstrated to support transplant function in various clinical trials and preclinical settings, but its effects on the balance between regulatory T cells (Tregs) and effector T cells (Teffs), as well as complement activation, are less well investigated. In the present study, we proposed to investigate the effects of CTLA4-Ig mediated immunosuppression on the phase of immunotolerance and the subsequent graft microvascular and epithelial repair during the progression of subepithelial fibrosis in a mouse model of orthotopic trachea transplantation. Briefly, CTLA4-Ig treated allografts (2 mg/kg, I.P.), untreated allografts, and syngrafts were serially monitored for peripheral FOXP3+ Tregs, antibody-mediated complement activation (C3d and C4d), tissue oxygenation, donor-recipient microvascular blood flow, and subsequent tissue remodeling following transplantation. Our data demonstrate that CTLA4-Ig mediated immunosuppression significantly results in late increases in both peripheral CD4+/CD8+ FOXP3+ Tregs and serum IL-10, but prevents the microvascular deposition of IgG, complement factor C3d, and epithelial C4d respectively, which proportionally improved blood flow and tissue oxygenation in the graft and, thus, promotes graft repair. Also, it restored the airway lumen, epithelium, and prevented the progression of subepithelial collagen deposition up to 90 days after transplantation. This study demonstrates that CTLA4-Ig-mediated immunosuppression potentially modulates both effector response and a late surge of regulatory activity to preserve graft microvasculature and rescue allograft from sustained hypoxia and ischemia and thereby limits subepithelial fibrosis.

A59 A RARE PRESENTATION OF COLLAGENOUS GASTRODUODENITIS WITH 10 YEAR FOLLOW UP

Abstract Background Collagenous gastritis(CG) is a rare form of gastritis defined histologically by the presence of &amp;gt;10um of subepithelial surface collagen deposition. CG can further be categorized in childhood onset CG and adult onset CG. The prevalence of childhood CG is 2.1/100,000 in children aged younger than 18. Adult onset CG remains a rare entity. Here, we describe a rare presentation of collagenous gastroduodenitis in an adult patient and the interval progression over a 10 year period. Aims To increase awareness of a rare condition with limited data on available treatment modalities and clinical outcomes in adults. Methods Case Report Results A 35 year old female with no past medical history presented with worsening fatigue and increased shortness of breath with no overt gastrointestinal bleeding symptoms. There was no previous history of radiation exposure or family history of autoimmune disease. Laboratory investigations revealed iron deficiency anemia with a hemoglobin of 69 and a ferritin of 11. TTG serology and anti-parietal antibody was also negative. Esophagogastroduodenoscopy biopsies confirmed the diagnosis of collagenous gastritis localized to the gastric body with the presence of acute and chronic inflammatory changes. The patient was started on proton pump inhibitor therapy. In the interval period, the patient denies any new onset of gastrointestinal symptoms other than occasional heartburn. She remains iron deficient and requires regular iron infusions. Follow up endoscopy 10 years later now demonstrates diffuse mucosal abnormalities with a nodular contour involving the entire stomach and extending into the duodenal bulb. Biopsies showed features compatible with collagenous gastroduodenitis with active inflammation and pyloric metaplasia(Figure 1). There was atrophy of the stomach mucosa with no parietal cells identified and no endocrine hyperplasia. Immunostaining for Helicobacter pylori was negative. Flexible sigmoidoscopy was also performed revealing endoscopically normal colonic mucosa to the descending colon. Conclusions CG is a rare disease entity with unclear pathogenesis. Multiple case reports describe some association with autoimmune disease such as celiac disease. To date, no standard treatment has been identified for the management of CG. CG presents endoscopically with nodular changes, mucosal atrophy and collagen deposition. Over time, adult onset CG can progress to involve the entire stomach. Clinically, adult onset CG usually presents with a diarrhea predominant phenotype with associated collagenous colitis. Treatment modalities that have been trialed include PPI, corticosteroids, sucralfate, azathioprine,5-aminosalicylates, iron supplementation and hypoallergenic diets. Here we describe a rare presentation of collagenous gastroduodenitis and subsequent 10 year follow up in order to better understand this disease entity. Funding Agencies None

The STAT6 inhibitor AS1517499 reduces the risk of asthma in mice with 2,4-dinitrochlorobenzene-induced atopic dermatitis by blocking the STAT6 signaling pathway

BackgroundEpidemiological studies have revealed a link between atopic dermatitis (AD) and asthma. AS1517499, a selective signal transducer and activation of transcription 6 (STAT6) inhibitor, has been shown to effectively block this connection. In this study, we further explored the underlying mechanism by constructing an AD mouse model.MethodsFemale BALB/c mice were randomly divided into four groups (n = 10/group). The AD mouse model was established by 2,4-dinitrochlorobenzene induction with repeated ovalbumin challenge. AS1517499 and corn oil were used as treatment interventions. The features of airway inflammation, remodeling, and hyperactivity were analyzed.ResultsActive use of AS1517499 in AD mice effectively reduced Th2-related cytokine levels, alleviated airway eosinophil and lymphocyte infiltration, and regulated GATA3/Foxp3 levels and subepithelial collagen deposition. These changes might be due to specific blockade of the STAT6 signaling pathway.ConclusionAS1517499 could partially block the association between AD and asthma by specifically inhibiting the STAT6 signaling pathway.

Lysyl oxidase like 2 is increased in asthma and contributes to asthmatic airway remodelling.

BackgroundAirway smooth muscle (ASM) cells are fundamental to asthma pathogenesis, influencing bronchoconstriction, airway hyperresponsiveness and airway remodelling. The extracellular matrix (ECM) can influence tissue remodelling pathways; however, to date no study has investigated the effect of ASM ECM stiffness and cross-linking on the development of asthmatic airway remodelling. We hypothesised that transforming growth factor-β (TGF-β) activation by ASM cells is influenced by ECM in asthma and sought to investigate the mechanisms involved.MethodsThis study combines in vitro and in vivo approaches: human ASM cells were used in vitro to investigate basal TGF-β activation and expression of ECM cross-linking enzymes. Human bronchial biopsies from asthmatic and nonasthmatic donors were used to confirm lysyl oxidase like 2 (LOXL2) expression in ASM. A chronic ovalbumin (OVA) model of asthma was used to study the effect of LOXL2 inhibition on airway remodelling.ResultsWe found that asthmatic ASM cells activated more TGF-β basally than nonasthmatic controls and that diseased cell-derived ECM influences levels of TGF-β activated. Our data demonstrate that the ECM cross-linking enzyme LOXL2 is increased in asthmatic ASM cells and in bronchial biopsies. Crucially, we show that LOXL2 inhibition reduces ECM stiffness and TGF-β activation in vitro, and can reduce subepithelial collagen deposition and ASM thickness, two features of airway remodelling, in an OVA mouse model of asthma.ConclusionThese data are the first to highlight a role for LOXL2 in the development of asthmatic airway remodelling and suggest that LOXL2 inhibition warrants further investigation as a potential therapy to reduce remodelling of the airways in severe asthma.

Proteome-Wide Analysis Using SOMAscan Identifies and Validates Epidermal Growth Factor as a Disease Marker of Collagenous Gastritis

Background and AimsCollagenous gastritis (CG) is a rare disorder characterized by increased subepithelial collagen deposition and inflammatory infiltrates. The mechanisms involved in CG pathogenesis are poorly understood, and no CG-associated biomarkers have been identified. This proteomics study identified serum biomarkers and pathogenic pathways to provide new knowledge about the pathobiology of CG, a disease reported in less than 100 patients.MethodsNine serum samples from pediatric patients diagnosed with CG were evaluated using novel aptamer-based proteomic technology and systems biology to generate new knowledge about the complex interactions between the differentially expressed proteins and candidate upstream regulators, using the Ingenuity Pathway Analysis in patients with non-CG and patients with normal gastric biopsies or nongastritis (NG).ResultsSOMAscan analysis identified 63 proteins significantly dysregulated in CG as compared to non-CG or NG patients that converged around enhanced inflammatory response and immune cell migration but reduced vascular functions. Principal component analysis using 15 of those proteins accurately separated the CG cases from the 2 comparator control groups. Using immunoassays, serum epidermal growth factor concentrations in CG patients, a protein involved in collagen production, were confirmed to be significantly lower than those in gastritis/NG patients.ConclusionThis is the first comprehensive analysis of the proteome in CG patients that reveals metabolic pathways relating inflammation and fibrosis as well as a new potential role of epidermal growth factor as a disease biomarker. Collagenous gastritis (CG) is a rare disorder characterized by increased subepithelial collagen deposition and inflammatory infiltrates. The mechanisms involved in CG pathogenesis are poorly understood, and no CG-associated biomarkers have been identified. This proteomics study identified serum biomarkers and pathogenic pathways to provide new knowledge about the pathobiology of CG, a disease reported in less than 100 patients. Nine serum samples from pediatric patients diagnosed with CG were evaluated using novel aptamer-based proteomic technology and systems biology to generate new knowledge about the complex interactions between the differentially expressed proteins and candidate upstream regulators, using the Ingenuity Pathway Analysis in patients with non-CG and patients with normal gastric biopsies or nongastritis (NG). SOMAscan analysis identified 63 proteins significantly dysregulated in CG as compared to non-CG or NG patients that converged around enhanced inflammatory response and immune cell migration but reduced vascular functions. Principal component analysis using 15 of those proteins accurately separated the CG cases from the 2 comparator control groups. Using immunoassays, serum epidermal growth factor concentrations in CG patients, a protein involved in collagen production, were confirmed to be significantly lower than those in gastritis/NG patients. This is the first comprehensive analysis of the proteome in CG patients that reveals metabolic pathways relating inflammation and fibrosis as well as a new potential role of epidermal growth factor as a disease biomarker.

Collagenous Gastritis: Characteristics and Response to Topical Budesonide

Collagenous gastritis (CG) is a rare disorder characterized by subepithelial collagen deposition in the stomach. Standard medications have been only moderately successful in treating CG. We report results of a large, retrospective, open-label noncontrolled study of topical budesonide for CG, with an aim of establishing an alternative therapy for the disease. We identified patients treated for CG at Mayo Clinic (2000-2017) with topically targeted budesonide (TTB) in 2 formulations: open-capsule budesonide or compounded immediate-release budesonide capsule. Demographic, clinical, biochemical, and histologic variables were assessed for all patients before and after treatment. We identified 64 patients with CG (50 adults, 14 children). Most were female (68%), mean age was 41 ± 22.8 years, and body mass index was 23.1 ± 5.9 kg/m2. In most pediatric patients, CG presented with abdominal pain and anemia; in adults, CG presented more often with weight loss (P < .001). Collagenous sprue or colitis were more common in patients >50 years of age (83%) vs those 19-50 years of age (27%) or <19 years of age (50%) (P < .001). Of the patients treated with TTB, 89% had a clinical response to TTB (42% complete, 46% partial), and 88% had a histologic response (53% complete, 33% partial). Adults and children with CG have a wide variety of symptoms, and notably, TTB therapy produced clinical and histologic improvement after other therapy had failed.

Sinomenine Relieves Airway Remodeling By Inhibiting Epithelial-Mesenchymal Transition Through Downregulating TGF-β1 and Smad3 Expression In Vitro and In Vivo.

Airway remodeling is associated with dysregulation of epithelial-mesenchymal transition (EMT) in patients with asthma. Sinomenine (Sin) is an effective, biologically active alkaloid that has been reported to suppress airway remodeling in mice with asthma. However, the molecular mechanisms behind this effect remain unclear. We aimed to explore the potential relationship between Sin and EMT in respiratory epithelial cells in vitro and in vivo. First, 16HBE cells were exposed to 100 μg/mL LPS and treated with 200 μg/mL Sin. Cell proliferation, migration, and wound healing assays were performed to evaluate EMT, and EMT-related markers were detected using Western blotting. Mice with OVA-induced asthma were administered 35 mg/kg or 75 mg/kg Sin. Airway inflammation and remodeling detection experiments were performed, and EMT-related factors and proteins in the TGF-β1 pathway were detected using IHC and Western blotting. We found that Sin suppressed cell migration but not proliferation in LPS-exposed 16HBE cells. Sin also inhibited MMP7, MMP9, and vimentin expression in 16HBE cells and respiratory epithelial cells from mice with asthma. Furthermore, it decreased OVA-specific IgE and IL-4 levels in serum, relieved airway remodeling, attenuated subepithelial collagen deposition, and downregulating TGF-β1and Smad3 expression in mice with asthma. Our results suggest that Sin suppresses EMT by inhibiting IL-4 and downregulating TGF-β1 and Smad3 expression.

Pediatric Collagenous Gastritis: Clinical and Histologic Outcomes in a Large Pediatric Cohort.

The aim of the study was to present the clinical characteristics, treatment, and outcomes of pediatric collagenous gastritis (CG). This is a retrospective cohort study. Patients were identified via query of the institutional pathology database. Clinical data was obtained by review of medical records. Forty patients (57.5% female) were identified, mean age 11.3 ± 3.7 years (2-16years). Isolated CG was present in 66.7%, coexisting collagenous duodenitis (CD) in 17.5%, collagenous colitis (CC) in 7.5%, and collagenous ileitis in 2.5%. Atopic comorbidities were found in 25%, autoimmune comorbidities in 12.5%. Abdominal pain (77.5%), vomiting (65%), anemia (57.5%), nausea (55.5%), diarrhea (32.5%), anorexia (25.0%), weight loss (25%), gastrointestinal bleed (22.5%), poor growth (20%), poor weight gain (12.5%). All had abnormal endoscopic findings on esophago-gastro-duodenoscopy (EGD), most commonly gastric nodularity (77.5%), visible blood (20%), erosions/superficial ulcerations (10%), ulcers (7.5%). Histologically, all patients had increased subepithelial collagen deposition. A variety of medications aimed towards inflammation and symptomatic treatment were used. Patients with anemia received iron supplementation and responded. Otherwise, there was no significant association of clinical or histologic improvement with specific treatments. 87.5% reported improvement or resolution of symptoms at the last follow-up (34.8 ± 27.0 months). Persistent sub-epithelial collagen was noted in 73.1% on the last EGD. Despite persistent findings of increased sub-epithelial collagen deposition during the follow-up period, most patients with CG show remission or resolution of clinical symptoms. Anemia responds to iron supplementation in all patients.

IL-10 Mediated Immunomodulation Limits Subepithelial Fibrosis and Repairs Airway Epithelium in Rejecting Airway Allografts.

Interleukin-10 plays a vital role in maintaining peripheral immunotolerance and favors a regulatory immune milieu through the suppression of T effector cells. Inflammation-induced microvascular loss has been associated with airway epithelial injury, which is a key pathological source of graft malfunctioning and subepithelial fibrosis in rejecting allografts. The regulatory immune phase maneuvers alloimmune inflammation through various regulatory modulators, and thereby promotes graft microvascular repair and suppresses the progression of fibrosis after transplantation. The present study was designed to investigate the therapeutic impact of IL-10 on immunotolerance, in particular, the reparative microenvironment, which negates airway epithelial injury, and fibrosis in a mouse model of airway graft rejection. Here, we depleted and reconstituted IL-10, and serially monitored the phase of immunotolerance, graft microvasculature, inflammatory cytokines, airway epithelium, and subepithelial collagen in rejecting airway transplants. We demonstrated that the IL-10 depletion suppresses FOXP3+ Tregs, tumor necrosis factor-inducible gene 6 protein (TSG-6), graft microvasculature, and establishes a pro-inflammatory phase, which augments airway epithelial injury and subepithelial collagen deposition while the IL-10 reconstitution facilitates FOXP3+ Tregs, TSG-6 deposition, graft microvasculature, and thereby favors airway epithelial repair and subepithelial collagen suppression. These findings establish a potential reparative modulation of IL-10-associated immunotolerance on microvascular, epithelial, and fibrotic remodeling, which could provide a vital therapeutic option to rescue rejecting transplants in clinical settings.

Drug-induced Collagenous Sprue: A Reversible Small Bowel Mucosal Disorder

Collagenous sprue is an unusual small intestinal mucosal disorder characterized by flattened small intestinal mucosa, unusual sub-epithelial collagen deposits, increased intra-epithelial lymphocytes, often denuded epithelial cells and resistance to therapy, including a gluten-free diet. The disorder is heterogeneous with several potential causes now identified. Similar to sprue-like intestinal disease, collagenous sprue may be caused or precipitated by different pharmaceutical agents. Olmesartan, an angiotensin II inhibitor, often employed in treatment of hypertension, may cause a drug-induced form of sprue-like small intestinal disease with the pathological features of untreated celiac disease refractory to gluten-free diet treatment. In addition, collagenous sprue may be precipitated by olmesartan. Recognition and cessation of the medication has led to resolution of the small intestinal mucosal disorder without steroids or other treatment.

Mycophenolate-Associated Sprue-Like Intestinal Disease Evolving into Collagenous Sprue

A 43-yr old female with two prior renal transplants for renal failure associated with diabetes, retinopathy and coronary artery disease developed diarrhea. Her medications included mycophenolate mofetil, an immunosuppressive medication documented to cause sprue-like mucosal changes in the small intestine. Later studies revealed a small intestinal mucosal lesion characterized by marked crypt hyperplasia, villous atrophy and increased intra-epithelial lymphocytes. Serological studies for celiac disease were negative and repeated biopsies despite a strict gluten-free diet, revealed histopathological persistence of a severely abnormal sprue-like enteropathy. Eventually, further biopsies of her small intestine revealed superimposed changes characterized by dense sub-epithelial collagen deposits histochemically staining positive for trichrome, typical of collagenous sprue and representing an expansion of published pathological features of mycophenolate-associated small intestinal mucosal disease.