Letter to “Mapping of Ghrelin Gene Expression and Cell Distribution in the Stomach of Morbidly Obese Patients—a Possible Guide for Efficient Sleeve Gastrectomy Construction” Obesity Surgery (2012) 22:617–622. doi:10.1007/s11695-011-0585-9

Abstract

Sir, We read with interest the paper published by Goitein et al. [1] in your journal, and we would like to make some comments on this paper. The authors collected tissue samples from three different areas of the stomach of patients undergoing sleeve gastrectomy. These areas were described as fundus, body and pre-antral regions. It would be interesting to know the histological status of the gastric mucosa obtained from these regions. Frequently, the regional limits between the oxyntic and antral mucosa, and their topographical extensions may vary from patient to patient, especially in the presence of inflammatory changes. The authors did not find quantitative significant differences in the population of ghrelin-producing cells between the three areas studied, although a lower density was observed in the so-called “pre-antral region”. This apparently lower density of ghrelinproducing cells in this area may be explained by the presence of transitional gastric mucosa in which oxynto-peptic glands can be found interspersed with mucous glands, the latter typical of the antral mucosa. If this hypothesis is correct, at least in a number of patients, it could interfere in the final average of their ghrelin cell counts. In addition, this ghrelinproducing cell population of the “pre-antral” mucosa does not represent the real population of ghrelin-producing cells of the gastric antral mucosa. In our study [2] as well as in the paper of Choe et al. [3], ghrelin-producing cells were very scarce in the antral mucosa which is quite different from their high population that have been described in the oxyntic mucosa. Goitein et al. [1] found a relative small number (45±20 cells per ×10 microscopic field in the gastric body) of ghrelinproducing cells in comparison to our findings (108±34.2 cells/mm). The ×10 microscopic field is indicative of low magnification field and not of a high magnification field which is usually used for this kind of cell counts. Under the ×10 microscopic field, the number of ghrelin-producing cells should be much more numerous. The transformation of the average area of these microscopic fields in square millimeter could elucidate this apparent divergence. According to our results [2], a significant difference of the density of ghrelin-producing cells among morbidly obese patients with and without metabolic syndrome was demonstrated. This finding is in apparent agreement with variations in the serum levels of ghrelin in the presence of metabolic syndrome and other clinical conditions such as hypertension, hyperinsulinemia, and type 2 diabetes which have been reported [4, 5]. Therefore, the clinical data of the obese patients studied by Goitein et al. could also be helpful to our understanding of the behavior of gastric endocrine cells in these patients. Finally, we agree that knowledge of the distribution of ghrelin-producing cells in the gastric mucosa should be an important issue to be considered in the gastric surgical treatment of morbidly obese patients. F. A. N. Maksud (*) :A. J. A. Barbosa Laboratory of Digestive and Neuroendocrine Pathology, Federal University of Minas Gerais (UFMG), Av. Alfredo Balena 190, 30130-100 Belo Horizonte, Brazil e-mail: nfabiana@hotmail.com