Human Esophagus Research Articles

Peroral Endoscopic Myotomy in a Porcine Model: A Step to Achalasia Patients

See Peroral Endoscopic Myotomy for Treating Achalasia in an Animal Model: A Feasibility Study by Byoung Wook Bang, Young Chul Choi, Hyung Gil Kim, et al., on page 54-58 Achalasia is an idiopathic motility disorder that results from degeneration of the myenteric plexus in the wall of the esophagus and the lower esophageal sphincter (LES).1 In esophageal manometry, achalasia is characterized by impaired relaxation of LES and loss of peristalsis in the body of the esophagus. Achalasia results in severe dysphagia for solids and liquids. Additional symptoms can also develop such as chest pain, regurgitation, aspiration, weight loss, and irreversible dilatation of the esophageal body. The therapy for achalasia focuses on the forced relaxation of the LES by endoscopic method or surgery. The treatment modalities using endoscopy or surgery have mainly included endoscopic pneumatic dilation and laparoscopic Heller myotomy (LHM). Recently, peroral endoscopic myotomy (POEM) has been introduced as a novel endoscopic procedure for the treatment of achalasia. A submucosal esophageal myotomy was first described in a porcine model by Pasricha et al.,2 and POEM was first performed to achalasia patients by Inoue et al.3 Since 2010, several small-sized case series for POEM have shown safety and excellent short-term outcomes.4-6 The advantages of POEM are theoretically based on those of endoscopic operation such as no skin incisions, decreased pain, and less blood loss. Furthermore, POEM incorporates the advantage of LHM consisted of durable surgical myotomy and single procedure. A recent porcine study showed that the preservation of longitudinal muscle layer does not compromise the effectiveness of the myotomy.7 In a paper published in Clinical Endoscopy, Bang et al.8 reported a study that evaluated the feasibility of POEM in a porcine model. The authors showed successful POEM procedure and no definite perioperative complications in two mini pigs. After 2 weeks from POEM procedure, the histopathologic evaluation of the necropsy specimens revealed complete loss of the inner circular muscle and replaced fibrosis at the myotomy site. The authors concluded that POEM is a technically feasible treatment in the animal model. This study has several limitations. First, the authors used only two pigs in the study. Second, the observation period was short for follow-up after the procedure. Third, the authors did not perform esophageal manometry to analyze the difference of LES pressure before and after the procedure. However, this study seems to be a step for transition of the treatment method for achalasia in the near future. In addition, this study was the first animal study of POEM in Korea. The porcine model is the most useful animal model for training in POEM because of its anatomy being similar to that of humans, although the normal porcine esophagus is thinner than the human achalasia-affected esophagus. And the porcine esophageal submucosal space is softer and more easily dissected than in humans. However, ex vivo porcine explants are a useful model for training of POEM as well as in vivo training.9 Several clinical data for POEM in human have been recently published. They suggest that POEM may soon replace traditional esophageal myotomy as the surgical treatment of choice for achalasia. A major advantage of POEM is the ability to control myotomy length. In POEM, myotomy is usually performed more than 10 cm and may be as long as 25 cm in previous case series.10 In contrast, surgical myotomy can be performed only a maximum of 8 cm in the length. POEM also permits any myotomy length required and in any direction, without injury to surrounding structures. Therefore, POEM can be considered for surgically failed cases or previous POEM failure cases. These are very important and major advantages of POEM. In study of Bang et al.,8 the authors did not detect any evidences of complications in necropsy. However, previous human studies reported postoperative subcutaneous emphysema and pneumomediastinum on clinical grounds or computed tomography scan.9 Mild forms of pneumomediastinum or subcutaneous emphysema had no clinical consequences such as pneumomediastinum during thoracoscopic surgery. Other complications such as peritonitis, penumoperitoneum, and mucosal damage at the esophagogastric junction have been noted, too. However, most complications were ameliorated by conservative and medical treatment. Further long-term studies with a large number of patients from different centers are awaited. In Korea, few centers have performed POEM for achalasia patients since November 2011. The first Korean study of POEM in human will be published soon. However, further studies with a greater number of animals are still needed to evaluate other issues such as repeated sessions of myotomy, multiple myotomy at different sites, or training system using ex vivo or in vivo animal model.

Bond Graph modeling of the human esophagus and analysis considering the interference in the fullness of an individual by reducing mechanical esophageal flow

INTRODUCTION: This paper shows a proposal for the mathematical modeling of the human esophagus using Bond Graph formalism and the interference in the satiation of an individual by way of an Esophageal Flow Controller (EFC). Therefore, it was evaluated that there is a significant change in fall time that affects the process of human satiety when the diameter of the esophagus is reduced. METHODS: As a first study, the analysis did not consider all hypothetical influences; only the most important variables were considered. RESULTS: As a result, the order of the final equation was x ∈ ℜ10. Furthermore, the designed model can be classified as linear, established and time invariant. CONCLUSION: The simulation results allow us to conclude that using the EFC in order to reduce the esophageal diameter in the upper esophageal sphincter area of 3cm by 1 cm implies that the system response will be slower; and consequently this reduction will interfere with satiety.

Identification of Lineage-Uncommitted, Long-Lived, Label-Retaining Cells in Healthy Human Esophagus and Stomach, and in Metaplastic Esophagus

The existence of slowly cycling, adult stem cells has been challenged by the identification of actively cycling cells. We investigated the existence of uncommitted, slowly cycling cells by tracking 5-iodo-2'-deoxyuridine (IdU) label-retaining cells (LRCs) in normal esophagus, Barrett's esophagus (BE), esophageal dysplasia, adenocarcinoma, and healthy stomach tissues from patients. Four patients (3 undergoing esophagectomy, 1 undergoing esophageal endoscopic mucosal resection for dysplasia and an esophagectomy for esophageal adenocarcinoma) received intravenous infusion of IdU (200 mg/m(2) body surface area; maximum dose, 400 mg) over a 30-minute period; the IdU had a circulation half-life of 8 hours. Tissues were collected at 7, 11, 29, and 67 days after infusion, from regions of healthy esophagus, BE, dysplasia, adenocarcinoma, and healthy stomach; they were analyzed by in situ hybridization, flow cytometry, and immunohistochemical analyses. No LRCs were found in dysplasias or adenocarcinomas, but there were significant numbers of LRCs in the base of glands from BE tissue, in the papillae of the basal layer of the esophageal squamous epithelium, and in the neck/isthmus region of healthy stomach. These cells cycled slowly because IdU was retained for at least 67 days and co-labeling with Ki-67 was infrequent. In glands from BE tissues, most cells did not express defensin-5, Muc-2, or chromogranin A, indicating that they were not lineage committed. Some cells labeled for endocrine markers and IdU at 67 days; these cells represented a small population (<0.1%) of epithelial cells at this time point. The epithelial turnover time of the healthy esophageal mucosa was approximately 11 days (twice that of the intestine). LRCs of human esophagus and stomach have many features of stem cells (long lived, slow cycling, uncommitted, and multipotent), and can be found in a recognized stem cell niche. Further analyses of these cells, in healthy and metaplastic epithelia, is required.

Abstract CN06-01: Induction of oral cavity cancer in rats by (S)-N'-nitrosonornicotine, a constituent of smokeless tobacco

Abstract Smokeless tobacco products such as moist oral snuff are being promoted by the tobacco industry with a half billion dollars per year in advertising. It is likely that the prevalence of smokeless tobacco use will continue to increase in the U.S. Smokeless tobacco products are widely used in other parts of the world and are considered by the International Agency for Research on Cancer as causes of cancer of the oral cavity, esophagus and pancreas in humans. However, no previous study has reported the presence of a strong oral cavity carcinogen in these products. N'-Nitrosonornicotine (NNN) occurs in significant amounts in smokeless tobacco products, generally being found at levels of 1 - 10 μg/g tobacco. Since NNN has a chiral center, it exists as (S)- and (R)- enantiomers. (S)-NNN is the major enantiomer in smokeless tobacco products. While racemic NNN (a 50:50 mixture of (S)- and (R)-NNN) has been previously shown to cause esophageal tumors in rats, the carcinogenicity of the individual enantiomers has not been reported. Based on our published metabolism and DNA binding studies of (S)-NNN, we hypothesized that it might be a more powerful carcinogen than (R)-NNN and, furthermore, that it might cause oral cancer. Groups of 24 male F-344 rats were treated with either (S)-NNN (15 ppm), (R)-NNN (15 ppm), or racemic NNN (30 ppm) in the drinking water for 15-20 months. Necropsy of 20 rats treated with (S)-NNN demonstrated a 100% incidence of oral cavity tumors. More than 60 oral cavity tumors were observed, including benign and malignant tumors of the buccal mucosa, soft and hard palate, tongue, and pharynx. All rats also had esophageal tumors. (R)-NNN was significantly less carcinogenic than (S)-NNN. Racemic NNN also induced a high incidence of oral cavity and esophageal tumors. The results of this study demonstrate for the first time the presence of a strong oral cavity carcinogen in smokeless tobacco. (S)-NNN is a prime target for elimination from these products as a positive step toward cancer prevention. Citation Format: Stephen S. Hecht, Sandra James-Yi, Gerard O'Sullivan, Irina Stepanov, Mingyao Wang, Fekadu Kassie, Steven Carmella, Pramod Upadhyaya, Silvia Balbo. Induction of oral cavity cancer in rats by (S)-N'-nitrosonornicotine, a constituent of smokeless tobacco. [abstract]. In: Proceedings of the Eleventh Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2012 Oct 16-19; Anaheim, CA. Philadelphia (PA): AACR; Cancer Prev Res 2012;5(11 Suppl):Abstract nr CN06-01.

Human epididymis protein 4 is up-regulated in gastric and pancreatic adenocarcinomas

Upper gastrointestinal neoplasia in the esophagus, stomach, and pancreas is associated with the formation of preneoplastic metaplasias. We have previously reported the up-regulation of human epididymis protein 4 (HE4) in all metaplasias in the stomach of humans and mice. We have now sought to evaluate the expression of HE4 in metaplasias/preneoplastic precursors and cancers of the human stomach, pancreas, and esophagus. Tissue microarrays for gastric cancers, pancreatic cancers, and esophageal adenocarcinoma were stained with antibodies against HE4. Immunostaining was quantified by digital imaging, and the results were evaluated to assess the expression in metaplasias, the expression in cancer pathological subtypes, and the effects of expression on survival in patients with cancer. In patients with gastric cancer from Korea, HE4 was detected in 74% of intestinal and 90% of diffuse cancers, whereas in a gastric cancer cohort from Johns Hopkins, HE4 was detected in 74% of intestinal-type and 92% of diffuse cancers. Nevertheless, in both cohorts, there was no impact of HE4 expression on overall survival. In the esophagus, we observed the expression of HE4 in scattered endocrine cells within Barrett esophagus samples, but Barrett columnar metaplasias and HE4 were detected in only 2% of esophageal adenocarcinomas. Finally, in the pancreas, HE4 expression was not observed in pancreatic intraepithelial neoplasia lesions, but 46.8% of pancreatic adenocarcinomas expressed HE4. Still, we did not observe any influence of HE4 expression on survival. The results suggest that HE4 is up-regulated during gastric and pancreatic carcinogenesis.

Mechanistic Target of Rapamycin Small Interfering RNA and Rapamycin Synergistically Inhibit Tumour Growth in a Mouse Xenograft Model of Human Oesophageal Carcinoma

To investigate the effect of mechanistic target of rapamycin (mTOR)-specific small interfering RNA (siRNA) and rapamycin on tumour size and levels of hypoxia inducible factor 1α(HIF-1α), vascular endothelial growth factor (VEGF) and mTOR proteins, and mTOR mRNA, in a mouse xenograft model of human oesophageal carcinoma. Tumours were induced in BALB/c nude mice using the human oesophageal squamous cell carcinoma cell line, EC1, injected subcutaneously. Animals were divided into four treatment groups (n = 5 per group) after 7 days: control (phosphate buffered saline, daily intraperitoneal [i.p.] injection); 50 μg/kg rapamycin, daily i.p. injection; 3 μg/kg mTOR siRNA, daily i.p. injection; combined mTOR siRNA and rapamycin, daily i.p. injections. Tumour volume was measured 21 days after xenograft. Levels of mTOR, VEGF and HIF-1α were assessed via immunohistochemistry and in situ hybridization. mTOR siRNA and/or rapamycin significantly decreased tumour volume and levels of HIF-1α, VEGF and mTOR protein, and mTOR mRNA. Combination treatment was significantly more effective than either treatment alone. mTOR siRNA and/or rapamycin inhibited the growth of oesophageal carcinoma in vivo. This may represent a novel and effective treatment strategy for oesophageal carcinoma.

The val66met polymorphism of brain-derived neurotrophic factor is associated with human esophageal hypersensitivity

Recent evidence implicates brain-derived neurotrophic factor (BDNF) in visceral hypersensitivity and pain in functional gastrointestinal disorders. We hypothesized that presence of the val66met polymorphism in the BDNF gene would be linked to increased esophageal sensitivity to electrical stimulation. A total of 39 healthy volunteers (20 males, mean age 30) compliant with inclusion criteria after screening procedures were genotyped for BDNF polymorphisms and completed an Hospital Anxiety and Depression Scale (HADS) questionnaire. Sensory (ST) and pain (PT) thresholds in the proximal (PE) and distal (DE) esophagus were determined using electrical stimuli to a swallowed intraluminal catheter with bipolar electrodes by an investigator blinded to the subjects' genotype. For comparison, somatic ST and PT (hand and foot) were also tested. HADS scores together with esophageal and somatic thresholds were then correlated with BDNF polymorphism status. Eleven of 39 (28%) volunteers had at least one Met allele (Met carriers). When compared with Val/Val, Met carriers had lower esophageal PT (Median PT [mA]: Val/Val vs Met carriers, PE; 49.4 vs 44.3, P = 0.033, DE: 63.8 vs 55.4, P = 0.045) with higher proportion of Val/Val subjects in the upper quartile for PT in both PE (P = 0.021) and DE (P = 0.033), yet similar somatic PT (Median PT [mA] Hand; 33.6 vs 38.0, P = 0.22, Foot; 44.7 vs 44.0, P = 0.48). Sensitivity results were independent of anxiety (P = 0.66) and depression (P = 0.33) scores. val66met BDNF polymorphisms are associated with increased esophageal sensitivity to experimental electrical stimulation. Thus, BDNF genotype may be a useful biomarker for electrical sensitivity in the healthy human esophagus.

Effect of Akt on the function of esophageal squamous cancer cell Eca109 and the expression of vasculogenic mimicry-related genes

To investigate the inhibitory effect of siRNA targeting Akt on the biological behavior of esophagus squamous cell carcinoma cell line in vitro and to explore the relationship between Akt and vasculogenic mimicry (VM)-related genes in esophageal squamous cell carcinoma. The plasmid-harboring small interfering RNA targeting Akt was introduced into Eca109 cells by liposome-mediated transfection. The proliferation of Eca109 cell was determined by colony formation assay. The cellular migration was evaluated by Transwell migration assay. And three dimensional cell culture was employed to observe and count the number of capillary structure for each cell group. Flow cytometry (FCM) was used to detect the apoptotic rate of Eca109, Eca109/Neo and Eca109/siRNA Akt cells under normoxia exposure. The apoptotic rate was assessed by Annexin V/7-AAD double labeling. And the expressions of Akt and matrix metalloproteinase-2 (MMP-2) protein were detected by Western blotting. The results of Western blotting showed that the expression of Akt in stably transfected group were significantly lower than empty carrier and untransfected groups (0.03 ± 0.01 vs 1.49 ± 0.39 and 1.47 ± 0.41, both P < 0.05). Transwell migration assay showed that fewer Eca109/8 cells could move through the artificial basement membrane as compared with untransfected and empty carrier groups (48 ± 9 vs 128 ± 10 and 122 ± 11, both P < 0.05). Clone formation number of stably transfected group was significantly lower than empty carrier and untransfected groups (63 ± 7 vs 148 ± 11 and 163 ± 15, both P < 0.05). Annexin V/7-AAD double standard method demonstrated that the apoptotic rate of stably transfected group was much more than those of untransfected and empty carrier groups (12.2% ± 1.6% vs 4.8% ± 0.8% and 4.2% ± 0.8%, both P < 0.05). Eca109 and Eca109/Neo cells were capable of forming the in vitro structures of VM. And the number of tube-shaped structure in stably transfected group was markedly less than those of untransfected and empty carrier groups (14.0 ± 1.2 vs 30.0 ± 1.2 and 27.7 ± 1.5, both P < 0.05). MMP-2 protein expression in stably transfected group was less than those of untransfected and empty carrier groups (both P < 0.05). The PI(3)K/Akt pathway is involved in the regulation of VM formation in esophageal squamous cell carcinoma through the action of MMP-2. Blockade of this pathway may provide a new therapeutic approach to human esophagus squamous cell carcinoma.

Tu1124 Evidence for Altered P2X3 Gene Expression Associating With TRPV1 and Neurotrophic Factors in the Inflamed Human Esophagus

inflammatory cytokines (IL-8, COX-2, IL-1β, TNF-α, ICAM-1) by RT-PCR. Results: A single, 1-hour exposure to acidic bile salt media significantly increased HRE reporter activity in both NES-G4T (p=0.037) and NES-B10T (p=0.038) cell lines at 24 hours. Following a 10 minute exposure to acidic bile salt media, faint nuclear HIF-1α expression peaked by 2 hours, and decreased by 4 hours in NES-B10T cells. In contrast, nuclear HIF-2α protein increased by 1 hour, and further increased up to 4 hours; this strong and sustained increase in HIF-2α protein expression was confirmed in NES-G4T cells. Exposure to acidic bile salts increased mRNA expression levels of all the HIF-target pro-inflammatory cytokines evaluated in both cell lines. Conclusions: In esophageal squamous cell lines from patients with GERD, exposure to acidic bile salts caused an increase in HIF activity, a strong and sustained increase of HIF-2α nuclear protein, and increased mRNA expression levels of HIF-target pro-inflammatory cytokines. These findings support our hypothesis that exposure to acid and bile salts causes esophageal squamous cells to activate HIF-2α, which causes the secretion of the pro-inflammatory cytokines that mediate reflux esophagitis.

Tu1137 The Circular Smooth Muscle in the Human Esophagus Makes an Acute Angle With the Longitudinal Smooth Muscle on Autopsy Specimens and on High Resolution CT Scan. This Affects the Mechanics of Esophageal Shortening

Tu1137 The Circular Smooth Muscle in the Human Esophagus Makes an Acute Angle With the Longitudinal Smooth Muscle on Autopsy Specimens and on High Resolution CT Scan. This Affects the Mechanics of Esophageal Shortening

Abstract LB-91: Transcriptome analysis of esophageal squamous cell carcinoma by SAGE identifies a new biomarker, NRD1

Abstract Esophageal squamous cell carcinoma (ESCC) is one of the most common malignancies worldwide. Because most ESCC is diagnosed at advanced stages, the overall 5-year survival rate of ESCC still remains low in spite of the use of various treatment modalities. Therefore, identification of new diagnostic markers and therapeutic targets for ESCC is important. Serial Analysis of Gene Expression (SAGE) is one of the common comprehensive methods to analyze transcript expression levels, and enables the quantitative and simultaneous analysis of a large number of transcripts. To identify potential diagnostic markers and therapeutic targets for ESCC, the SAGE library was generated from one ESCC sample. A total of 14,430 tags were generated, including 5,765 that were unique. By comparing SAGE tags from the ESCC sample with those from normal human squamous esophagus, several genes that is upregulated in ESCC compared with normal squamous esophagus in ESCC were identified. Among these, we focused on the nardilysin (N-arginine dibasic convertase, NRD1) gene. NRD1 has been reported to be associated with ectodomein shedding of TNF-α through activation of ADAM proteases. There is only one report in the literature mentioning the association of NRD1 with cancer (breast cancer), however, there is no report that links expression of NRD1 and ESCC. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis showed a high level of NRD1 expression in three of five esophageal cancer cell lines and seven of 14 ESCC samples, but not in 14 normal systemic tissues. Western blot analysis also showed upregulation of NRD1 protein in total five esophageal cancer cell lines. Immunohistochemical analysis revealed expression of NRD1 in cytoplasm of 43 out of 109 ESCC cases (39%), as well as heart, skeletal muscle, and testis in agreement with previous reports. In clinicopathological analysis, expression of NRD1 correlated with the advanced T grade, N grade and tumor stage, and was an independent predictor of survival in patients with ESCC. Knockdown of NRD1 in TE5 cells inhibited cell invasion ability. Furthermore, qRT-PCR analysis showed a reduction of matrix metalloproteinase-2 (MMP-2) expression in NRD1 knocked down cells. In conclusion, NRD1 is an independent predictor of survival, and contribute to cell invasion through regulation of MMP-2 in ESCC. NRD1 could be a novel diagnostic and therapeutic target for ESCC. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-91. doi:1538-7445.AM2012-LB-91

Review: Experimental models for Barrett's esophagus and esophageal adenocarcinoma

Several different cell culture systems and laboratory animal models have been used over the years to study Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC). Most of the existing models have key differences with the human esophagus and complex pathogenesis of disease. None of the models offers an ideal system for the complex study of environmental exposure, genetic risk, and prevention strategies. In fact, different model systems may be required to answer different specific research questions about the pathogenesis of BE and EAC. Given the high mortality associated with EAC and the fact that current screening strategies miss most cases of EAC, advances in basic and translational science related to esophageal injury, repair, and carcinogenesis are clearly needed. This review describes several of the existing and potential model systems for BE and EAC with their benefits and disadvantages.

Bacterial flora of the human oral cavity, and the upper and lower esophagus

This reference study aims to survey the bacterial flora of the healthy lower human esophagus and to compare it with that of the upper esophagus and oral mucosa. The use of biopsies, in addition to brush samples, allows inclusion of not only transient bacteria present on the surface but also bacteria residing in the epithelia, and the yield of the two methods can be compared. Forty patients scheduled for surgery for reasons with no known influence on esophageal flora and with no symptoms or endoscopic signs of esophageal disease were included. Samples were collected from the oral, upper esophageal, and lower esophageal mucosa using sealed brushes and biopsy forceps. Colonies cultivated on agar plates were classified and semiquantified. Twenty-three different bacterial species were identified, with similar strains present at the three sites. The most common group of bacteria was viridans streptococci, with an occurrence rate in brush samples and biopsies of 98% and 95%, respectively. The median number of species occurring in the oral cavity, upper esophagus, and lower esophagus was between 3 and 4 (range 0-7). The total number of species in the oral cavity was significantly higher when compared with either level in the esophagus, while the yields obtained by brush and biopsy sampling were highly correlated. Hence, the normal human esophagus is colonized with a resident bacterial flora of its own, which has similarities to that of the oral mucosa. There are diverse species that make up this flora, although in relatively low amounts. The most frequent inhabitants of the esophagus are streptococci, with an occurrence rate in brush samples and biopsies of 95-98%. Comparative studies of patients with eosinophilic esophagitis and gastroesophageal reflux disease are warranted.

Deglutitive Inhibition, Latency Between Swallow and Esophageal Contractions and Primary Esophageal Motor Disorders

Swallowing induces an inhibitory wave that is followed by a contractile wave along the esophageal body. Deglutitive inhibition in the skeletal muscle of the esophagus is controlled in the brain stem whilst in the smooth muscle, an intrinsic peripheral control mechanism is critical. The latency between swallow and contractions is determined by the pattern of activation of the inhibitory and excitatory vagal pathways, the regional gradients of inhibitory and excitatory myenteric nerves, and the intrinsic properties of the smooth muscle. A wave of inhibition precedes a swallow-induced peristaltic contraction in the smooth muscle part of the human oesophagus involving both circular and longitudinal muscles in a peristaltic fashion. Deglutitive inhibition is necessary for drinking liquids which requires multiple rapid swallows (MRS). During MRS the esophageal body remains inhibited until the last of the series of swallows and then a peristaltic contraction wave follows. A normal response to MRS requires indemnity of both inhibitory and excitatory mechanisms and esophageal muscle. MRS has recently been used to assess deglutitive inhibition in patients with esophageal motor disorders. Examples with impairment of deglutitive inhibition are achalasia of the LES and diffuse esophageal spasm.

Circular smooth muscle contributes to esophageal shortening during peristalsis

To study the angle between the circular smooth muscle (CSM) and longitudinal smooth muscle (LSM) fibers in the distal esophagus. In order to identify possible mechanisms for greater shortening in the distal compared to proximal esophagus during peristalsis, the angles between the LSM and CSM layers were measured in 9 cadavers. The outer longitudinal layer of the muscularis propria was exposed after stripping the outer serosa. The inner circular layer of the muscularis propria was then revealed after dissection of the esophageal mucosa and the underlying muscularis mucosa. Photographs of each specimen were taken with half of the open esophagus folded back showing both the outer longitudinal and inner circular muscle layers. Angles were measured every one cm for 10 cm proximal to the squamocolumnar junction (SCJ) by two independent investigators. Two human esophagi were obtained from organ transplant donors and the angles between the circular and longitudinal smooth muscle layers were measured using micro-computed tomography (micro CT) and Image J software. All data are presented as mean ± SE. The CSM to LSM angle at the SCJ and 1 cm proximal to SCJ on the autopsy specimens was 69.3 ± 4.62 degrees vs 74.9 ± 3.09 degrees, P = 0.32. The CSM to LSM angle at SCJ were statistically significantly lower than at 2, 3, 4 and 5 cm proximal to the SCJ, 69.3 ± 4.62 degrees vs 82.58 ± 1.34 degrees, 84.04 ± 1.64 degrees, 84.87 ± 1.04 degrees and 83.72 ± 1.42 degrees, P = 0.013, P = 0.008, P = 0.004, P = 0.009 respectively. The CSM to LSM angle at SCJ was also statistically significantly lower than the angles at 6, 7 and 8 cm proximal to the SCJ, 69.3 ± 4.62 degrees vs 80.18 ± 2.09 degrees, 81.81 ± 1.75 degrees and 80.96 ± 2.04 degrees, P = 0.05, P = 0.02, P = 0.03 respectively. The CSM to LSM angle at 1 cm proximal to SCJ was statistically significantly lower than at 3, 4 and 5 cm proximal to the SCJ, 74.94 ± 3.09 degrees vs 84.04 ± 1.64 degrees, 84.87 ± 1.04 degrees and 83.72 ± 1.42 degrees, P = 0.019, P = 0.008, P = 0.02 respectively. At 10 cm above SCJ the angle was 80.06 ± 2.13 degrees which is close to being perpendicular but less than 90 degrees. The CSM to LSM angles measured on virtual dissection of the esophagus and the stomach on micro CT at the SCJ and 1 cm proximal to the SCJ were 48.39 ± 0.72 degrees and 50.81 ± 1.59 degrees. Rather than the angle of the CSM and LSM being perpendicular in the esophagus we found an acute angulation between these two muscle groups throughout the lower 10 cm of the esophagus. The oblique angulation of the CSM may contribute to the significantly greater shortening of distal esophagus when compared to the mid and proximal esophagus during peristalsis.

Acid modulates the squamous epithelial barrier function by modulating the localization of claudins in the superficial layers

Acid is a major cause of gastro-esophageal reflux disease. However, the influence of acid on the esophageal stratified epithelial barrier function and tight junction (TJ) proteins is not fully understood. Here, we explore the influence of acid on barrier function and TJ proteins using a newly developed model of the esophageal-like squamous epithelial cell layers that employs an air–liquid interface (ALI) system. Barrier function was determined by measuring trans-epithelial electrical resistance (TEER) and diffusion of paracellular tracers. TJ-related protein (claudin-1, claudin-4, occludin and ZO-1) expression and localization was examined by immunofluorescent staining, and by western blotting of 1% NP-40 soluble and insoluble fractions. We also examined the influence of acid (pH 2–4) on the barrier created by these cells. The in vitro ALI culture system showed a tight barrier (1500–2500 Ω·cm2) with the expression of claudin-1, claudin-4, occludin and ZO-1 in the superficial layers. Claudin-1, claudin-4, occludin and ZO-1 were detected as dots and whisker-like lines in the superficial layers, and as a broad line in the suprabasal layers. These localization patterns are similar to those in the human esophagus. On day 7 under ALI culture, TJ proteins were detected in the superficial layers with functional properties, including decreased permeability and increased TEER. Dilated intercellular spaces were detected at the suprabasal cell layers even under the control conditions of ALI cells. pH 2 acid on the apical side significantly reduced the TEER in ALI-cultured cells. This decrease in TEER by the acid was in parallel with the decreased amount of detergent-insoluble claudin-4. Claudin-4 delocalization was confirmed by immunofluorescent staining. In conclusion, TJs are located in the superficial layers of the esophagus, and acid stimulation disrupts barrier function, at least in part by modulating the amount and localization of claudin-4 in the superficial layers.

Using fluorine-containing amphiphilic random copolymers to manipulate the quantum yields of aggregation-induced emission fluorophores in aqueous solutions and the use of these polymers for fluorescent bioimaging.

Two new series of aggregation-induced emission (AIE) fluorophore-containing amphiphilic copolymers possessing the segments of a monomeric AIE fluorophore, N-(2-hydroxypropyl)methacrylamide (HPMA), [2-(methacryloyloxy)ethyl]trimethylammonium chloride (MATMA), and/or 2,2,2-trifluoroethyl methacrylate (TFEMA) were synthesized. Photophysical properties were investigated using UV-Vis absorbance and fluorescence spectrofluorometry. The increases of molar fractions of the hydrophobic AIE fluorophores and/or the trifluoroethyl moieties result in the higher quantum yields of the AIE fluorophores in the polymers. Using 1-mol% of AIE fluorophores with the tuning of molar fractions of TFEMA, 40% quantum yield was achieved, whereas only less than 10% quantum yield was obtained for the polymers without the TFEMA segments. The quantum yield difference indicates the importance of the fluorine segments for getting high quantum yields of the AIE fluorophores. These polymers were explored for fluorescent bioimaging using human brain glioblastoma U87MG and human esophagus premalignant CP-A cell lines. All the polymers are cell permeable and located in the cellular cytoplasma area. Cellular uptake was demonstrated to be through endocytosis, which is time and energy dependent. The polymers are non-cytotoxic to the two cell lines. Because the polymers contain (19)F segments, we studied the spin-lattice relaxation time (T1) and spin-spin relaxation time (T2) of these polymers. T1 and T2 are the two important parameters for the evaluations of the capacity of these polymers for further applications in (19)F magnetic resonance imaging ((19)F MRI). Structure influence on T1 and T2, especially for T2, was observed. These new multifunctional materials are the first series of fluorinated polymers with AIE fluorophores for bioapplications.

Optical frequency domain imaging system and catheters for volumetric imaging of the human esophagus.

Barrett's esophagus (BE) is a metaplastic disorder that can undergo dysplastic progression, leading to esophageal adenocarcinoma. Upper endoscopy is the standard of care for screening for BE, but this technique has a relatively low diagnostic accuracy and high cost due to the requirement of conscious sedation. Optical frequency domain imaging (OFDI) is a high-speed imaging modality that generates cross-sectional images of tissues with a resolution of approximately 10μm that is sufficient for detecting microscopic tissue architecture. In combination with a balloon-centering catheter, this method enables BE diagnosis over the entire distal esophagus.

Barrett's metaplasia glands are clonal, contain multiple stem cells and share a common squamous progenitor

BackgroundLittle is known about the stem cell organisation of the normal oesophagus or Barrett's metaplastic oesophagus. Using non-pathogenic mitochondrial DNA mutations as clonal markers, the authors reveal the stem cell...

Math1/Atoh1 Contributes to Intestinalization of Esophageal Keratinocytes by Inducing the Expression of Muc2 and Keratin-20

Esophageal intestinal metaplasia, also known as Barrett's esophagus, is the replacement of the normal epithelium with one that resembles the intestine morphologically. Generally, this includes intestinal mucin-secreting goblet cells. Barrett's esophagus is an important risk factor for adenocarcinoma development. In-vitro models for Barrett's esophagus have not, to date, focused on the induction of goblet cells in Barrett's epithelium. To explore the contribution of Math1/Atoh1 to induction of Barrett's esophagus and intestinal mucin-secreting goblet cells from normal human esophageal epithelium. We explored the level and pattern of Math1/Atoh1 mRNA and protein expression in human Barrett's esophagus. Then, using retroviral-mediated gene expression, we induced Math1 mRNA and protein expression in a human esophageal keratinocyte cell line. We evaluated the effects of this ectopic Math1 expression on cell proliferation and gene expression patterns in cells cultured under two-dimensional and three-dimensional tissue-engineering conditions. Math1/Atoh1 mRNA and protein are detected in human Barrett's esophagus specimens, but the mRNA levels vary substantially. In the keratinocyte expression studies, we observed that Math1/Atoh1 ectopic expression significantly reduced cell proliferation and altered cell morphology. Moreover, Math1/Atoh1 expression is associated with a more intestinalized gene expression pattern that is distinct from that reported in after studies using other intestinal transcription factors. Most significantly, we observe the induction of the Barrett's esophagus markers Mucin-2 and Keratin-20 with Math1/Atoh1 expression. We conclude that ectopic Math1/Atoh1 expression makes unique contributions to intestinalization of the esophageal epithelium in Barrett's esophagus.