During a wound repair process in rats, metaplastic columnar-lined esophagus was produced and increased in length following esophagojejunostomy, which may be independent of stem cell reprogramming, according to results from an anastomosed rodent study.
The investigators studied esophageal and tissue sections of 52 rats at different time points after esophagojejunostomy and samples were analyzed for length, type, and location of columnar lining. In addition, the sections were examined immunophenotypically to elucidate the molecular changes that occur during ulceration. Agoston T. Agoston, MD, PhD, of Brigham and Women’s Hospital and the department of pathology at Harvard Medical School, Boston, and colleagues reportedin Cellular and Molecular Gastroenterology and Hepatology.
“This rodent columnar-lined esophagus has been proposed to develop from cellular reprogramming of progenitor cells, but studies on early columnar-lined esophagus development are lacking,” the researchers wrote.
In the model, ulceration was seen 2 weeks after surgery, which began distally at the esophagojejunal anastomosis. Representative of wound healing, reepithelialization of the ulcer region took place through formation of immature glands, which were found to bud directly from jejunal crypts.
After immunophenotypic analysis, the researchers reported that “immunohistochemical characterization of neoglandular epithelium located immediately proximal to the anastomosis showed features similar to those of the native nonproliferating jejunal epithelium located immediately distal to the anastomosis.” They further reported that “the columnar-lined esophagus’s immunoprofile was similar to jejunal crypt epithelium.”
Upon further examination of the ulcer segment, Dr. Agoston and colleagues found that columnar-lined esophagus elongated from 0.15 mm (standard error of the mean, ± 0.1) to 5.22 mm (SEM, ± 0.37) at 2 and 32 weeks post esophagojejunostomy, respectively.
“There was a highly significant linear relationship between the length of the neoglandular epithelium in the distal esophagus and the number of weeks after surgery (correlation coefficient, 0.94; P less than .0001),” the investigators stated.
Locational analysis revealed epithelial-mesenchymal transition markers being expressed by spindle-shaped cells at the leading edge of the columnar-lined esophagus. In addition, neoglands were identified within esophageal ulcer beds and actively dividing squamous epithelium was seen exclusively at the proximal ulcer border.
Following the systematic analysis, the authors noted that the columnar-lined esophagus was most likely the result of jejunal cell migration into the esophagus. They suggested that if compared, jejunal cells may competitively dominate squamous cells in the context of chronic gastroesophageal reflux disease. Furthermore, they observed that the region of ulceration following esophagojejunostomy in their model was more expansive than that reported in other comparable rodent models of reflux esophagitis.
“The reason for this difference is not clear, but we speculate that it is the result of technical aspects of our reflux-inducing surgery,” the researchers wrote. They further explained that “we intentionally fashioned a large anastomotic orifice between the esophagus and jejunum, perhaps larger than that fashioned by other investigators.” And they concluded, “we suspect that this larger orifice resulted in esophageal exposure to larger volumes of refluxate and, consequently, larger areas of ulceration.”
The authors acknowledged their results may not be fully applicable in the context of human Barrett’s esophagus, given the rodent model. However, they do believe the findings may provide a basis to help understand the wound repair process, particularly the distal edge of ulcers that border the columnar epithelium.
“Using a rat model of reflux esophagitis via surgical esophagojejunostomy, we have shown that a metaplastic, columnar-lined esophagus develops via a wound healing process, and not via genetic reprogramming of progenitor cells,” the researchers concluded.
The study was supported by grant funding from the National Institutes of Health and the Baylor Scott and White Research Institute. The authors reported no conflicts of interest.
SOURCE: Agoston AT et al. Cell Mol Gastroenterol Hepatol. 2018 Jun 26. doi: 10.1016/j.jcmgh.2018.06.007.