Clonal transitions and phenotypic evolution in Barrett esophagus

BACKGROUND & AIMS: Barrett's esophagus (BE) is a risk factor for esophageal adenocarcinoma but our understanding of how it evolves is poorly understood. We investigated BE gland phenotype distribution, the clonal nature of phenotypic change, and how phenotypic diversity plays a role in progression. METHODS: Using immunohistochemistry and histology, we analyzed the distribution and the diversity of gland phenotype between and within biopsy specimens from patients with nondysplastic BE and those who had progressed to dysplasia or had developed postesophagectomy BE. Clonal relationships were determined by the presence of shared mutations between distinct gland types using laser capture microdissection sequencing of the mitochondrial genome. RESULTS: We identified 5 different gland phenotypes in a cohort of 51 nondysplastic patients where biopsy specimens were taken at the same anatomic site (1.0-2.0 cm superior to the gastroesophageal junction. Here, we observed the same number of glands with 1 and 2 phenotypes, but 3 phenotypes were rare. We showed a common ancestor between parietal cell-containing, mature gastric (oxyntocardiac) and goblet cell-containing, intestinal (specialized) gland phenotypes. Similarly, we have shown a clonal relationship between cardiac-type glands and specialized and mature intestinal glands. Using the Shannon diversity index as a marker of gland diversity, we observed significantly increased phenotypic diversity in patients with BE adjacent to dysplasia and predysplasia compared to nondysplastic BE and postesophagectomy BE, suggesting that diversity develops over time. CONCLUSIONS: We showed that the range of BE phenotypes represents an evolutionary process and that changes in gland diversity may play a role in progression. Furthermore, we showed a common ancestry between gastric and intestinal-type glands in BE

Evaluation Of Probiotics On Constipation

The present study aimed to better understand and evaluate the potential effects of Lactobacillus sp. as probiotic and its mechanism to alleviate constipation as the alternative therapeutic intervention for constipation treatment to lactulose in the aging animal model. The probiotic properties of L. fermentum DR9, L. plantarum DR7, L. sakei Probio65 and L. casei Y were characterized in the present study

Ageing the Barrett's Lesion: A Study of Evolution to Oesophageal Adenocarcinoma

Barrett’s oesophagus (BO), a metaplasia affecting the distal oesophagus, is the only known precursor for oesophageal adenocarcinoma (OAC) which, despite advances in healthcare, continues to carry a dire prognosis. The emergence of BO has been shown to have polyclonal origins forming a mosaic of distinct geno-phenotypic clones across the space. However, the precise transformative cellular population, rate of clonal expansion and subsequent neighbouring clonal dynamics that promote a benign or malignant course remain unknown. Recent work has demonstrated the ability to use the sequence of epigenetic methylation marks, which are somatically inherited at mitosis, as a marker of clonal ancestry, mutational ordering in progression and to determine mitotic age in colorectal adenomas and cancer. Characterisation of the dynamics that underpin stem cell behaviour, which ultimately are the precursor cells for the cancer phenotype, can also be inferred by mapping methylation patterns at high resolution across epithelium. These techniques are transferrable to BO, another epithelial, glandular and clonal disease, and form the primary modus operandi of this thesis. This thesis adds to the debate regarding whether there is a particular dwell time to cancer; whether there is a mitotic age that predicts it; where and how the BO lesion expands at inception and varies over its natural history; the turnover of glandular phenotypes and whether they follow a linear or direct evolution to cancer; and how molecular diversity can be a proxy marker for cancer risk. I have designed a novel targeted allele specific methylation sequencing (ASM-Seq) array that utilises modern next generation sequencing technology to significantly enhance resolution and coverage over previous studies. Furthermore, my protocol is the first of its type in a cytosine deaminated DNA template that incorporates unique molecular identifiers (UMIs) in efforts to reduce confounders in sequencing data. Targeted ASM-Seq has the potential to reveal the intricate tissue dynamics not just of BO but any disease characterised by a clonal organisation and ancestry. Ultimately, this understanding will assist in better targeting of surveillance, clinical resources and therapies to patients deemed at risk of OAC

High Goblet Cell Count Is Inversely Associated with Ploidy Abnormalities and Risk of Adenocarcinoma in Barrett’s Esophagus

<div><p>Purpose</p><p>Goblet cells may represent a potentially successful adaptive response to acid and bile by producing a thick mucous barrier that protects against cancer development in Barrett's esophagus (BE). The aim of this study was to determine the relationship between goblet cells (GC) and risk of progression to adenocarcinoma, and DNA content flow cytometric abnormalities, in BE patients.</p><p>Experimental Design</p><p>Baseline mucosal biopsies (N=2988) from 213 patients, 32 of whom developed cancer during the follow up period, enrolled in a prospective dynamic cohort of BE patients were scored in a blinded fashion, for the total number (#) of GC, mean # of GC/crypt (GC density), # of crypts with ≥ 1 GC, and the proportion of crypts with ≥1 GC, in both dysplastic and non-dysplastic epithelium separately. The relationship between these four GC parameters and DNA content flow cytometric abnormalities and adenocarcinoma outcome was compared, after adjustment for age, gender, and BE segment length.</p><p>Results</p><p>High GC parameters were inversely associated with DNA content flow cytometric abnormalities, such as aneuploidy, ploidy >2.7N, and an elevated 4N fraction > 6%, and with risk of adenocarcinoma. However, a Kaplan-Meier analysis showed that the total # of GC and the total # crypts with ≥1 GC were the only significant GC parameters (p<0.001 and 0.003, respectively).</p><p>Conclusions</p><p>The results of this study show, for the first time, an inverse relationship between high GC counts and flow cytometric abnormalities and risk of adenocarcinoma in BE. Further studies are needed to determine if GC depleted foci within esophageal columnar mucosa are more prone to neoplastic progression or whether loss of GC occurs secondary to underlying genetic abnormalities.</p></div