Club Cell Loss as a Feature of Bronchiolization in ILD.

Background: Distal airway metaplasia may precede honeycombing in progressive fibrosing interstitial lung disease (ILD). The SCGB1A1+ bronchiolar-specific club cell may play a role in this aberrant regenerative process. Objective: To assess the presence of club cells in the small airways of patients suffering from ILD. Methods: Small airways (internal diameter <2 mm) in lung samples [surgical lung biopsy (SLB) and/or transbronchial lung cryobiopsy (TBLC)] from 14 patients suffering from ILD and 10 controls were morphologically assessed and stained for SCGB1A1. SCGB1A1 was weighted by epithelial height as a marker of airway generation (SCGB1A1/EH). Correlations between clinical, functional, and high-resolution CT (HRCT) prognostic factors and histomorphometry were assessed. Results: Small airways from samples with ILD patterns were significantly less dense in terms of SCGB1A1+ cells [0.064 (0.020-0.172)] as compared to controls' sample's small airways [0.393 (0.082-0.698), p < 0.0001]. Usual interstitial pneumonia (UIP) patterns most frequently contained small airways with limited or absent SCGB1A1 expression (SCGB1A1/EH <0.025): UIP (18/33; 55%) as compared with non-UIP patterns (4/31; 13%) or controls (0/29; 0%): p < 0.0001. In addition, correlations with HRCT indicated a significant negative relationship between SCGB1A1 and bronchiectasis as a feature of bronchiolization (Rho -0.63, p < 0.001) and a positive relationship with both forced vital capacity (FVC) and Hounsfield unit (HU)-distribution pattern in kurtosis (Rho 0.38 and 0.50, respectively, both p < 0.001) as markers of fibrotic changes. Conclusion: Compared with controls, the small airways of patients with ILD more often lack SCGB1A1, especially so in UIP. Low densities of SCGB1A1-marked cells correlate with bronchiectasis and fibrotic changes. Further research investigating SCGB1A1 staining as a pathological feature of the bronchiolization process is merited.

Low Levels of Alcohol Consumption and Risk of Intestinal Metaplasia: A Cohort Study.

BACKGROUND: The impact of alcohol drinking on gastric precancerous lesions remains unclear. We investigated the relationship of alcohol intake with risk of atrophic gastritis (AG) and intestinal metaplasia (IM). METHODS: This study included 202,675 Korean adults free from AG and IM on their initial endoscopy who were followed with repeated endoscopic examinations. A parametric proportional hazards model was used to estimate the adjusted HR (aHR) with 95% confidence interval (CI) for incident AG and IM based on endoscopic diagnosis. RESULTS: During a mean follow-up of 4.7 years, 64,853 incident AG cases and 4,536 IM cases were identified. Alcohol consumption including drinking frequency, quantity, and binge drinking were consistently associated with increased risk of both AG and IM in a dose-response manner. After adjustment for confounders, the multivariable aHRs (95% CIs) for incident IM comparing average alcohol intake of <10, 10-<20, 20-<40, and ≥40 g/day with lifetime abstainers were 1.27 (1.02-1.56), 1.34 (1.07-1.66), 1.50 (1.20-1.86), and 1.54 (1.23-1.93), respectively. Former drinkers were also at a higher risk for AG and IM compared with lifetime abstainers. These associations were consistently observed in never smokers and in time-dependent analyses. CONCLUSIONS: In a large cohort of Korean individuals, alcohol intake even at low levels was independently associated with increased risk of developing endoscopic AG and IM, supporting a role of alcohol consumption in the pathogenesis of AG and IM, the precursor lesions of stomach cancer. IMPACT: Alcohol consumption from low-level drinking may contribute to gastric carcinogenesis.

Regenerative Metaplastic Clones in COPD Lung Drive Inflammation and Fibrosis.

Chronic obstructive pulmonary disease (COPD) is a progressive condition of chronic bronchitis, small airway obstruction, and emphysema that represents a leading cause of death worldwide. While inflammation, fibrosis, mucus hypersecretion, and metaplastic epithelial lesions are hallmarks of this disease, their origins and dependent relationships remain unclear. Here we apply single-cell cloning technologies to lung tissue of patients with and without COPD. Unlike control lungs, which were dominated by normal distal airway progenitor cells, COPD lungs were inundated by three variant progenitors epigenetically committed to distinct metaplastic lesions. When transplanted to immunodeficient mice, these variant clones induced pathology akin to the mucous and squamous metaplasia, neutrophilic inflammation, and fibrosis seen in COPD. Remarkably, similar variants pre-exist as minor constituents of control and fetal lung and conceivably act in normal processes of immune surveillance. However, these same variants likely catalyze the pathologic and progressive features of COPD when expanded to high numbers.

Fibrocartilaginous metaplasia and neovascularization of the anterior cruciate ligament in patients with osteoarthritis.

INTRODUCTION: The anterior cruciate ligament (ACL) prevents the anterior translocation and medial rotation of the tibia against the femur. It is typically composed of dense regular connective tissue (DRCT), small amount of loose connective tissue, little vasculature, and few nerve endings. The objective of the current study was to evaluate the details of histological changes in ACLs of patients with clinically diagnosed osteoarthritis (OA). MATERIALS AND METHODS: The ACLs of six patients undergoing total knee replacement because of OA (OA group) were compared with 16 normal ACLs from cadavers (control). The ACLs were analyzed for tissue composition and number of blood vessels across the full length and thickness of the ligament. Percentages for areas of DRCT, fibrocartilage, degenerative tissue, and vasculature were calculated. Tissue composition and relative number of blood vessels were compared between groups. RESULTS: The proportion of DRCT to non-DRCT was significantly smaller in the OA group than the control group (p < .001); non-DRCT included degenerative connective tissue and fibrocartilage. The number of blood vessels to area was greater in the OA group than the control group (p = .002). Six of control (37.5%) and five of OA ACLs (83%) showed areas of calcification. CONCLUSIONS: These results indicate that inflammatory processes contributing to OA in the knee cause changes in the composition of the ACL that lead to destruction of collagen bundles, increased vascularization, calcification, and formation of fibrocartilage-like tissue inside the ligament. These changes make ligament-retaining total knee arthroplasty a less beneficial option for knee repair.

Proliferation and Differentiation of Gastric Mucous Neck and Chief Cells During Homeostasis and Injury-induced Metaplasia.

BACKGROUND & AIMS: Adult zymogen-producing (zymogenic) chief cells (ZCs) in the mammalian gastric gland base are believed to arise from descending mucous neck cells, which arise from stem cells. Gastric injury, such as from Helicobacter pylori infection in patients with chronic atrophic gastritis, can cause metaplasia, characterized by gastric cell expression of markers of wound-healing; these cells are called spasmolytic polypeptide-expressing metaplasia (SPEM) cells. We investigated differentiation and proliferation patterns of neck cells, ZCs, and SPEM cells in mice. METHODS: C57BL/6 mice were given intraperitoneal injections of high-dose tamoxifen to induce SPEM or gavaged with H pylori (PMSS1) to induce chronic gastric injury. Mice were then given pulses of 5-bromo-2'-deoxyuridine (BrdU) in their drinking water, followed by chase periods without BrdU, or combined with intraperitoneal injections of 5-ethynyl-2'-deoxyuridine. We collected gastric tissues and performed immunofluorescence and immunohistochemical analyses to study gastric cell proliferation, differentiation, and turnover. RESULTS: After 8 weeks of continuous BrdU administration, fewer than 10% of homeostatic ZCs incorporated BrdU, whereas 88% of neck cells were labeled. In pulse-chase experiments, various chase periods decreased neck cell label but did not increase labeling of ZCs. When mice were given BrdU at the same time as tamoxifen, more than 90% of cells were labeled in all gastric lineages. After 3 months' recovery (no tamoxifen), ZCs became the predominant BrdU-labeled population, whereas other cells, including neck cells, were mostly negative. When we tracked the labeled cells in such mice over time, we observed that the proportion of BrdU-positive ZCs remained greater than 60% up to 11 months. In mice whose ZCs were the principal BrdU-positive population, acute injury by tamoxifen or chronic injury by H pylori infection resulted in SPEM cells becoming the principal BrdU-positive population. After withdrawal of tamoxifen, BrdU-positive ZCs reappeared. CONCLUSIONS: We studied mice in homeostasis or with tamoxifen- or H pylori-induced SPEM. Our findings indicated that mucous neck cells do not contribute substantially to generation of ZCs during homeostasis and that ZCs maintain their own census, likely through infrequent self-replication. After metaplasia-inducing injury, ZCs can become SPEM cells, and then redifferentiate into ZCs on injury resolution.

The Reduction in Gastric Atrophy after Helicobacter pylori Eradication Is Reduced by Treatment with Inhibitors of Gastric Acid Secretion.

BACKGROUND: Helicobacter pylori (H. pylori) eradication therapy may improve gastric atrophy and intestinal metaplasia, but the results of previous studies have not always been consistent. The aim of this study was to compare the histological changes of intestinal metaplasia and gastric atrophy among the use of acid-suppressing drugs after H. pylori eradication. METHODS: A cohort of 242 patients who underwent successful eradication therapy for H. pylori gastritis and surveillance endoscopy examination from 1996 to 2015 was analyzed. Changes in the histological scores of intestinal metaplasia and atrophy according to drug use (proton-pump inhibitors (PPIs), H2 receptor antagonists (H2RAs), and non-acid suppressant use) were evaluated in biopsies of the antrum and corpus using a generalized linear mixed model in all patients. RESULTS: The mean follow-up period and number of biopsies were 5.48 ± 4.69 years and 2.62 ± 1.67 times, respectively. Improvement in the atrophy scores of both the antrum (p = 0.042) and corpus (p = 0.020) were significantly superior in patients with non-acid suppressant drug use compared with those of PPI and H2RA use. Metaplasia scores in both the antrum and corpus did not improve in all groups, and no significant differences were observed among groups in the antrum (p = 0.271) and corpus (p = 0.077). CONCLUSIONS: Prolonged acid suppression by PPIs or H2RAs may limit the recovery of gastric atrophy following H. pylori eradication.

Mimicking and Manipulating Pancreatic Acinar-to-Ductal Metaplasia in 3-dimensional Cell Culture.

The differentiation of acinar cells to ductal cells during pancreatitis and in the early development of pancreatic cancer is a key process that requires further study. To understand the mechanisms regulating acinar-to-ductal metaplasia (ADM), ex vivo 3D culture and differentiation of primary acinar cells to ductal cells offers many advantages over other systems. With the technique herein, modulation of protein expression is simple and quick, requiring only one day to isolate, stimulate or virally infect, and begin culturing primary acinar cells to investigate the ADM process. In contrast to using basement membrane matrix, the seeding of acinar cell clusters in collagen I extracellular matrix, allows acinar cells to retain their acinar identity before manipulation. This is vital when testing the contribution of various components to the induction of ADM. Not only are the effects of cytokines or other ectopically administered factors testable through this technique, but the contribution of common mutations, increased protein expression, or knockdown of protein expression is testable via viral infection of primary acinar cells, using adenoviral or lentiviral vectors. Moreover, cells can be re-isolated from collagen or basement membrane matrix at the endpoint and analyzed for protein expression.

Cellular Origins of Barrett's Esophagus: the Search Continues.

PURPOSE OF REVIEW: The cellular origins of Barrett's esophagus remain elusive. In this review, we discuss the potential cellular mechanisms behind squamous to columnar metaplasia as well as the limitations of these proposed mechanisms. RECENT FINDINGS: Several theories have been proposed, including the reprogramming of native squamous cells, repopulation from submucosal glands, contributions from circulating bone marrow-derived cells, and direct extension of gastric cells. Most recent data support an innate progenitor cell unique to the squamocolumnar junction that can expand into metaplastic glands. Active investigation to clarify each of these potential cells of origin is being pursued, but ultimately each could contribute to the pathogenesis of Barrett's esophagus depending on the clinical context. Nonetheless, identifying cells of origin is critical to understand the molecular mechanisms behind Barrett's esophagus and developing strategies to better treat (and possibly prevent) this increasingly significant premalignant disease.

Endoscopic Surveillance After Repair of Oesophageal Atresia: Longitudinal Study in 209 Patients.

AIM: After repair of oesophageal atresia (OA), the need for endoscopic follow-up (EFU) remains unclear. To end this, we assessed the trends of oesophageal mucosal changes in successive follow-up biopsies. METHODS: EFU records of 264 patients including histological grades of oesophagitis (from 0 to III), gastric (GM) or intestinal (IM) metaplasia and dysplasia (mild to severe) at 1, 3, 5 10, 15, and >15 years after repair of OA were reviewed. RESULTS: Included were 209 patients with 616 biopsies. A total of 60 patients had undergone antireflux surgery and 24 had long-gap OA (LG). Median follow-up was 12 (range 1-17) years with 3 (1-6) endoscopies per patient. Highest grade of oesophagitis was Gr 0 (no oesophagitis) in 47%, Gr I in 37%, and Gr II or III in 16%. Metaplasia, GM (n = 31), IM (n = 4), occurred in 17% of patients and reached 15% prevalence by 15 years. Dysplasia and cancer were not found. From 1 to 15 years after repair grade of histological oesophagitis often fluctuated between Gr 0 and Gr I, but further progression was unlikely, hazard ratio = 0.2-3.4 (95% confidence interval 0.0-29), P = 0.06-0.87. LG and antireflux surgery predicted early detection of metaplasia (P < 0.001). Only 9% of patients with metaplasia and 32% with Gr II oesophagitis were symptomatic. A total of 6 (3%) patients had a symptomatic anastomotic stenosis at 1 year. CONCLUSIONS: EFU revealed frequent oesophagitis and metaplasia, but no dysplasia or cancer. Routine endoscopic surveillance had limited benefit and seems unnecessary during childhood after repair of OA.

Etiopathogenesis of acquired cholesteatoma: prominent theories and recent advances in biomolecular research.

OBJECTIVE: To review recent biomolecular advances in etiopathogenesis of acquired cholesteatoma. DATA SOURCES: MEDLINE via OVID (to March 2014) and PubMed (to March 2014). REVIEW METHODS: All articles referring to etiopathogenesis of acquired cholesteatoma were identified in the above databases, from which 89 articles were included in this review. RESULTS: The mechanisms underlying the etiopathogenesis of acquired cholesteatoma remain a subject of competing hypotheses. Four theories dominate the debate, including theories of invagination, immigration, squamous metaplasia, and basal cell hyperplasia. However, no single theory has been able to explain the clinical characteristics of all cholesteatoma types: uncoordinated hyperproliferation, invasion, migration, altered differentiation, aggressiveness, and recidivism. Modern technologies have prompted a number of researchers to seek explanations at the molecular level. First, cholesteatomas could be considered an example of uncontrolled cell growth, capable of altering the balance toward cellular hyperproliferation and enhancing the capacity for invasion and osteolysis. Second, the dysregulation of cell growth control involves internal genomic or epigenetic alterations and external stimuli, which induce excessive host immune response to inflammatory and infectious processes. This comprises several complex and dynamic pathophysiologic changes that involve extracellular and intracellular signal transduction cascades. CONCLUSIONS: This article summarizes the existing theories and provides conceptual insights into the etiopathogenesis of acquired cholesteatoma, with the aim of stimulating continued efforts to develop a nonsurgical means of treating the disorder.

Squamous cell carcinogenesis and squamous cell carcinoma of the urinary bladder: a contemporary review with focus on nonbilharzial squamous cell carcinoma.

Bladder squamous cell carcinoma, squamous metaplasia, and transitional cell carcinoma with squamous differentiation are infrequent findings in Western countries. A common risk factor for their development consists of chronic bladder irritation and inflammation. The prognostic and clinical relevance and natural history of squamous cell lesions has been under investigation, revealing individual premalignant characteristics. Recent developments in molecular characterization of squamous alterations of the urinary tract indicate pathogenetic similarities and interrelations and might lead to more precise tumor classification and risk stratification in the future. Nevertheless, current clinical management of patients with premalignant and malignant bladder squamous cell lesions remains challenging, as high evidence level studies are not available and prognosis of invasive squamous carcinoma is poor. Our review summarizes the available data on clinical presentation, treatment, and outcome of bladder squamous cell carcinoma, metaplastic lesions, and transitional cell carcinoma with squamous differentiation and discusses implementable current advances in the understanding of bladder cancer tumorigenesis.

Mechanistic insights into the contribution of epithelial damage to airway remodeling. Novel therapeutic targets for asthma.

It has been suggested that an inherent airway epithelial repair defect is the root cause of airway remodeling in asthma. However, the relationship between airway epithelial injury and repair, airway remodeling, and airway hyperresponsiveness (AHR) has not been directly examined. We investigated the contribution of epithelial damage and repair to the development of airway remodeling and AHR using a validated naphthalene (NA)-induced murine model of airway injury. In addition, we examined the endogenous versus exogenous role of the epithelial repair peptide trefoil factor 2 (TFF2) in disease pathogenesis. A single dose of NA (200 mg/kg in 10 ml/kg body weight corn oil [CO] vehicle, intraperitoneally) was administered to mice. Control mice were treated with CO (10 ml/kg body weight, intraperitoneally). At 12, 24, 48, and 72 hours after NA or CO injection, AHR and various measures of airway remodeling were examined by invasive plethysmography and morphometric analyses, respectively. TFF2-deficient mice and intranasal treatment were used to examine the role of the epithelial repair peptide. NA treatment induced denudation and apoptosis of airway epithelial cells, goblet cell metaplasia, elevated AHR, and increased levels of endogenous TFF2. Airway epithelial changes peaked at 12 hours after NA treatment, whereas airway remodeling changes were observed from 48 hours. TFF2 was protective against epithelial damage and induced remodeling and was found to mediate organ protection via a platelet-derived growth factor-associated mechanism. Our findings directly demonstrate the contribution of epithelial damage to airway remodeling and AHR and suggest that preventing airway epithelial damage and promoting epithelial repair may have therapeutic implications for asthma treatment.

Numb regulates acinar cell dedifferentiation and survival during pancreatic damage and acinar-to-ductal metaplasia.

BACKGROUND & AIMS: Pancreatic ductal adenocarcinoma (PDA) is a leading cause of cancer-related death. Through the process of acinar-to-ductal metaplasia (ADM), pancreatic acinar cells give rise to pancreatic intraepithelial neoplasia (PanIN), the most common precursor of PDA. However, even when Kras is activated in a majority of acinar cells, ADM and subsequent development of PanINs is inefficient in the absence of additional stresses. Numb regulates cell junctions, integrins, and the activity of embryonic signaling pathways; therefore, we investigated its effects on acinar cell dedifferentiation, regeneration, and metaplasia. METHODS: We used mouse models of pancreatic regeneration and PDA as well as mice with loss-of-function alleles of Numb (p48Cre/p48Cre(ER);Numb(f/f) and p48Cre/p48Cre(ER);Kras(G12D);Numb(f/f) mice) to study the roles of Numb in pancreatic regeneration and ADM. RESULTS: Loss of Numb resulted in premature dedifferentiation of acinar cells in response to injury due to administration of the cholecystokinin analogue cerulein and interfered with acinar cell regeneration. Numb was found to regulate multiple signaling pathways in acinar cells during cerulein-induced pancreatitis. Disruption of Numb accelerated and destabilized ADM in the context of oncogenic Kras (in p48Cre;Kras(G12D);Numb(f/f) and p48Cre(ER);Kras(G12D);Numb(f/f) mice). CONCLUSIONS: Numb is an important regulator of acinar cell differentiation and viability during metaplasia. In mice with pancreatitis or pancreatic injury, elimination of Numb causes dedifferentiated acinar cells to undergo apoptosis, and this is not mitigated by oncogenic Kras.

Association of TMEM16A chloride channel overexpression with airway goblet cell metaplasia.

The TMEM16A protein has a potential role as a Ca(2+)-activated Cl(-) channel (CaCC) in airway epithelia where it may be important in the homeostasis of the airway surface fluid. We investigated the function and expression of TMEM16A in primary human bronchial epithelial cells and in a bronchial cell line (CFBE41o-). Under resting conditions, TMEM16A protein expression was relatively low. However, TMEM16A silencing with short-interfering RNAs caused a marked inhibition of CaCC activity, thus demonstrating that a low TMEM16A expression is sufficient to support Ca(2+)-dependent Cl(-) transport. Following treatment for 24-72 h with interleukin-4 (IL-4), a cytokine that induces mucous cell metaplasia, TMEM16A protein expression was strongly increased in approximately 50% of primary bronchial epithelial cells, with a specific localization in the apical membrane. IL-4 treatment also increased the percentage of cells expressing MUC5AC, a marker of goblet cells. Interestingly, MUC5AC was detected specifically in cells expressing TMEM16A. In particular, MUC5AC was found in 15 and 60% of TMEM16A-positive cells when epithelia were treated with IL-4 for 24 or 72 h, respectively. In contrast, ciliated cells showed expression of the cystic fibrosis transmembrane conductance regulator Cl(-) channel but not of TMEM16A. Our results indicate that TMEM16A protein is responsible for CaCC activity in airway epithelial cells, particularly in cells treated with IL-4, and that TMEM16A upregulation by IL-4 appears as an early event of goblet cell differentiation. These findings suggest that TMEM16A expression is particularly required under conditions of mucus hypersecretion to ensure adequate secretion of electrolytes and water.

Unión escamo columnar y metaplasia intestinal en esófago: magnificación y FICE / Scomo columnar junction and intestinal metaplasia in esophagus: diagnosis with magnyfication and FICE

La endoscopia estándar no identifica Metaplasia Intestinal en Esófago. Su presencia se ha relacionado con el tipo de Unión Escamo Columnar. La endoscopia de alta resolución con magnificación, colorantes vitales y virtuales aumenta su diagnostico. Asociar la presencia de Metaplasia Intestinal con el tipo de Unión Escamo Columnar, utilizando endoscopia de alta resolución, magnificación y Cromoscopia Virtual con FICE corroborándolo con histología. Previo consentimiento verbal se incluyeron prospectivamente a los individuos que tenían indicación electiva de endoscopia digestiva superior. Se utilizó para endoscopia digestiva superior equipo Fujinon Inc. EG 590 ZW, con procesador EPX 4400 que provee efecto FICE con Cromoscopia Virtual Computada. Se utilizó magnificación y FICE. Se clasificó la Unión Escamo Columnar según Wallner en cuatro tipos y se correlacionaron con la presencia de Metaplasia Intestinal. Se grabó en DVD, se congeló durante 3 segundos la imagen deseada y se fotografió cada hallazgo de interés guardado en JPEG en programa Power Point. Se tomó biopsia del patrón sugestivo de Metaplasia Intestinal. Los patólogos evaluaron las láminas sin tener datos del paciente. Se incluyeron 120 pacientes (p): 44 hombres y 76 mujeres con edad de 20-85 años. Se identificaron los tipos de Unión Escamo Columnar y patrones de mucosa descritos en la literatura y se correlacionaron con la histología. La Unión Escamo Columnar tipo GII se encontró en 45,09% y el Patrón Pit T3 se asoció en 87,5% con GIII. Con FICE se evalúa e identifica mejor el tipo de Unión Escamo Columnar y Metaplasia Intestinal con buena correlación histológica

Barrett´s esophagus is an endoscopic diagnosis stablished when Intestinal Metaplasia is found histologically. We described the association of the type of Scamo columnar Junction (SCJ) described by Wallner et al and pit pattern (PP) classification by Toyoda et al suggestive of Intestinal Metaplasia using High Resolution endoscopy with Magnification and FICE. Salmon and red colored Tongues of columnar epithelium oriented to biopsy the esophagus. SCJ type GII was found in 45,09% and T3 PP in 60,86% of GII and 87,6% of GIII. Our results showed that type o SCJ helps and alert of the presence of Intestinal Metaplasia

Mucosal barrier defects in gastric intestinal metaplasia: in vivo evaluation by confocal endomicroscopy.

BACKGROUND: Helicobacter pylori infection and intestinal metaplasia (IM) are associated with gastric cancer. An impaired gastric mucosal barrier could be involved in this carcinogenesis. OBJECTIVE: To evaluate laser confocal laser endomicroscopy (CLE) for in vivo functional imaging of mucosal barrier defects in patients with IM. DESIGN: Prospective, controlled study. SETTING: A tertiary-care academic center. PATIENTS: This study involved patients with IM of the gastric mucosa who underwent CLE for surveillance. INTERVENTIONS: Specific IM mucosa and non-IM mucosa in patients were identified by CLE, and targeted biopsy samples were taken for histopathology and electron microscopy. MAIN OUTCOME MEASUREMENTS: Post-CLE assessment of paracellular fluorescein leakage was devised and validated by electron microscopy. We also evaluated the effect of H pylori eradication on the mucosal barrier. RESULTS: Forty-two patients were included. Of non-IM samples, the paracellular permeability was significantly increased in H pylori-positive samples compared with H pylori-negative controls (54 ± 31% vs 3 ± 6%, P < .05). Of IM samples, the permeability was significantly increased in both H pylori-negative and H pylori-positive samples (67 ± 34% and 72 ± 28% vs 3 ± 6%, both P < .05). The results of post-CLE assessment correlated well with the electron microscopy findings (R(2) 0.834, P < .0001). After the eradication of H pylori, the paracellular barrier dysfunction of non-IM mucosa was significantly improved as shown by electron microscopy and CLE (both P < .001). However, there was no significant change in IM mucosa. LIMITATIONS: Single-center study. CONCLUSIONS: CLE allows functional imaging of mucosal barrier defects. Gastric IM is associated with an impaired paracellular barrier irrespective of H pylori eradication.

The clonal origins of dysplasia from intestinal metaplasia in the human stomach.

BACKGROUND & AIMS: Studies of the clonal architecture of gastric glands with intestinal metaplasia are important in our understanding of the progression from metaplasia to dysplasia. It is not clear if dysplasias are derived from intestinal metaplasia or how dysplasias expand. We investigated whether cells within a metaplastic gland share a common origin, whether glands clonally expand by fission, and determine if such metaplastic glands are genetically related to the associated dysplasia. We also examined the clonal architecture of entire dysplastic lesions and the genetic changes associated with progression within dysplasia. METHODS: Cytochrome c oxidase-deficient (CCO⁻) metaplastic glands were identified using a dual enzyme histochemical assay. Clonality was assessed by laser capture of multiple cells throughout CCO⁻ glands and polymerase chain reaction sequencing of the entire mitochondrial DNA (mtDNA) genome. Nuclear DNA abnormalities in individual glands were identified by laser capture microdissection polymerase chain reaction sequencing for mutation hot spots and microsatellite loss of heterozygosity analysis. RESULTS: Metaplastic glands were derived from the same clone-all lineages shared a common mtDNA mutation. Mutated glands were found in patches that had developed through gland fission. Metaplastic and dysplastic glands can be genetically related, indicating the clonal origin of dysplasia from metaplasia. Entire dysplastic fields contained a founder mutation from which multiple, distinct subclones developed. CONCLUSIONS: There is evidence for a distinct clonal evolution from metaplasia to dysplasia in the human stomach. By field cancerization, a single clone can expand to form an entire dysplastic lesion. Over time, this field appears to become genetically diverse, indicating that gastric cancer can arise from a subclone of the founder mutation.