El diafragma, el hiato y la unión gastroesofágica / The diaphragm, the hiatus and the gastroesophageal junction

RESUMEN La unión del tubo esofágico con el estómago en lo que denominamos el cardias, su tránsito y relacio nes con el hiato diafragmático, las estructuras fibromembranosas que la fijan y envuelven, la existencia de un esfínter gastroesofágico anatómico y su real morfología, así como la interacción de todos estos elementos, han sido materia de controversia por décadas y aún hoy. Este artículo actualiza la descrip ción de tales estructuras.

ABSTRACT The point where the esophagus connects to the stomach, known as the cardia, its transition and re lationship with the diaphragmatic hiatus, its fibromembranous attachments, the existence of an ana tomic gastroesophageal sphincter and its real morphology, and the interaction between all these ele ments, have been subject of debate for decades that still persist. The aim of this article is to describe the updated information of such structures.

[Morphological features of the esophagogastric transition zone at fetuses and newborns].

Morphological research of the esophagogastric transition mucosa at 35 fetuses and newborns was done. The esophagogastric transition was lined by high columnar epithelium and mucos glands. At fetuses of 22-24 week gestational age studied zone didn't have any glands. Histochemical features of the epithelium, particularly MUC5AC positive staining, corresponded to cardial type of the Barrett esophagus, defined at adults. We have revealed that mucosa of the esophagogastric transition has gastric origin and arises before birth. We found out the islets of columnar epithelium on the surface of the laminated pavement epithelium, indicated about its uneven development up to the birth. The sites of immature epithelium could be considered as transformation zones both of laminated pavement epithelium or columnar one.

Controversies of cardiac glands in the proximal stomach: a critical review.

Cardiac glands (CG), along with oxyntocardiac glands, in a normal human constitute cardiac mucosa (CM) that is positioned in the proximal stomach with a length of 10-30 mm, according to traditional teaching. This doctrine has been recently challenged. On the basis of studies on autopsy and biopsy materials in the esophagogastric junction region, some investigators have reported the presence of CG in only 50% of the general US population. They believed that CG were an acquired, metaplastic lesion as a result of gastroesophageal reflux disease. Subsequent recent study results from other research groups showed the presence of CG in the proximal stomach in embryos, fetuses, pediatric, and adult patients in most Europeans and Americans, and almost all Japanese and Chinese patients. These new data showed the following important findings: (i) CG are confirmed to be congenital in the proximal stomach; (ii) the length of CM is much shorter, approximately 5 mm in Caucasians in Europe and North America, and approximately 13 mm in Japanese and probably also in Chinese; (iii) CG are also present in the distal superficial esophagus underneath squamous mucosa in almost all Japanese and Chinese patients, but not so common in Caucasians in Europe, and not clear in Caucasians in North America. The recent data indicate a clear difference in the distribution of CG in the proximal stomach among different ethnic populations, and might explain different disease pathogenesis mechanisms among various ethnic patient groups.

[The pathophysiology of motor disorders of cardioesophageal transition in children].

The review highlighted some issues on ontogeny of the nervous system of the esophagus. Data on burdened heredity role and gestosis risk of the pregnancy interruption in the development of GERD in childhood are presented. The role of nitrergic and serotoninergic systems and prostaglandins in the development of GERD in children is discussed.

On the origin of cardiac mucosa: a histological and immunohistochemical study of cytokeratin expression patterns in the developing esophagogastric junction region and stomach.

AIM: To examine the fetal and neonatal esophagogastric junction region (EGJ) histologically for the presence of an equivalent to adult cardiac mucosa (CM); to study the expression patterns of all cytokeratins (CK) relevant to the EGJ during gestation; to compare the CK profile of the gestational and the adult EGJ; and to determine the degree of development in the adult EGJ histology and CK profile during gestation. METHODS: Forty-eight fetal autopsy specimens of the EGJ were step-sectioned and stained with hematoxylin and eosin (H and E) to select sections showing the mucosal lining. Immunohistochemistry for CK5, 7, 8, 13, 18, 19, and 20 was performed. Antibody staining was then graded for location, intensity, and degree. RESULTS: The distal esophagus was lined by simple columnar epithelium from 12-wk gestational age (GA). The proximal part of this segment consisted of mucus-producing epithelium, devoid of parietal cells. CK5 and 13 were present exclusively in multilayered epithelia and CK8, 18, and 19 predominantly in simple columnar epithelium. There were no differences in the frequencies of the co-ordinate CK7+/20+ and the CK7-/20- immunophenotypes between different locations. The prevalence of the CK7+/20- immunophenotype decreased, and that of the CK7-/20+ immunophenotype increased significantly from the distal esophagus to the distal stomach. CONCLUSION: Fetal columnar-lined lower esophagus (fetal CLE) may be the equivalent and precursor of the short segments of columnar epithelium found in the distal esophagus of some normal adult subjects. Esophageal simple columnar epithelium without parietal cells (ESN) may be the precursor of adult CM. The similarities between the fetal and adult EGJ and stomach CK expression patterns support the conclusion that adult CM has an identifiable precursor in the fetus. This would then indicate that at least a part of the adult CM has a congenital origin.

The histological findings in the gastroesophageal junction of fetuses.

The development of the esophageal and gastric mucosa in the gastroesophageal junction was studied in 61 fetuses of 13-41 weeks of the gestational age. During the 13th-15th week, the esophageal multilayered epithelium was covered by a continuous layer of columnar mucous ciliated cells which were present only focally till the 25th week and disappeared later. Before the 15th week, the gastric mucosa was formed by pits only. The glands started as proliferating tubules in the basal parts of the pits in the 15th week. Further, they differentiated into oxyntic glands. The mucosa of the corpus was fully developed in the 27th week. The cardiac mucosa was absent in all the 10 fetuses examined between the 27th and 41st week of gestation. This supports the view that the gastric cardiac mucosa is not a physiological structure but that it results from glandular metaplasia of the distal esophageal mucosa due to gastroesophageal reflux.

On the existence and location of cardiac mucosa: an autopsy study in embryos, fetuses, and infants.

BACKGROUND: The incidence of gastric cardiac adenocarcinoma has increased in the last decades. Gaining insight into the pathogenesis of this lesion is hampered by the limited knowledge of the origin and histology of cardiac mucosa (CM). Currently, the location, extent, and even the existence of CM are controversial. AIMS: We studied the development of the gastro-oesophageal junction (GOJ) in embryos, fetuses, and infants to clarify if CM is a normal structure at birth and where it is located. SUBJECTS: Twenty one autopsy cases were evaluated ranging in age from 13 weeks' gestational age (GA) to seven months. METHODS: The distal oesophagus and proximal part of the stomach were embedded entirely. Serial sections were stained with haematoxylin-eosin and alcian blue/periodic acid-Schiff. The following parameters were measured: length of abdominal oesophagus; length of columnar lined oesophagus; length of CM; and distance from CM to angle of His. RESULTS: CM was present in all evaluated sections. Its mean length varied throughout gestation. A maximum value was reached at a GA of 16 weeks (1.2 mm). After term delivery it was very short (0.3-0.6 mm). CM was proximal to, or straddled, the angle of His in all cases. During gestation, the mucin staining pattern of the CM was to a high degree similar to that of the developing pyloric mucosa. CONCLUSIONS: CM develops during pregnancy and is present at birth as a normal structure. If the angle of His is taken as a landmark for the GOJ, CM is located in the distal oesophagus.

Origin of cardiac mucosa: ontogenic consideration.

The origin and histology of the cardiac mucosa remains controversial. The classical concept that the cardiac mucosa is of gastric origin has been challenged by those who advocate that the cardiac mucosa results from a metaplastic esophageal process. Some regard cardiac mucosa as consisting solely of pure mucous glands, whereas others accept the presence of isolated parietal cells within the mucous gland (mixed glands). In this study, we have clarified the presence and site of origin of the cardiac mucosa and its histological composition. To do so we studied the microscopic characteristics of the gastric side of the squamous-columnar junction (SCJ) of 77 autopsied fetuses of different gestational ages (prenatal group) and of infants, young children, and adolescents (postnatal group). We evaluated the presence or absence of a transitional zone, defined as the area between the squamous esophageal and oxyntic mucosa, the glandular composition of the transitional zone (i.e., pure mucous and mixed glands), and the presence or absence of inflammation. Our study revealed that a transitional zone with the microscopic characteristics of cardiac mucosa was universally present at the SCJ. The microscopic characteristics of this zone varied with age. Both pure mucous and mixed glands were observed. We conclude that the cardiac mucosa is partially if not entirely the result of normal embryonic gastric development. Both mucous and mixed glands constitute normal components of the cardiac mucosa.

Immunocytochemical study on the triple origin of the sphincter iris in the chick embryo.

The ontogenic development of the sphincter iris has been studied by immunocytochemistry and standard staining on chick embryos from stage 25 HH to the time of hatching. We have used the monoclonal antibody 13F4, a highly specific marker of muscular cells. We have observed three different regions in the iris. In the pupillary region, immunoreactive cells are in continuous contact with the inner epithelium of the pupillary margin. In the intermediate region, the outer epithelium forms buds of pigmented cells that emigrate toward the stroma. In this epithelium cells that are totally or partially unpigmented exist, and they are 13F4 positive. In the sphincter we have observed 13F4 positive cells with melanin granules. In the ciliary region, the immunoreactivity appears in dispersed mesenchymal cells. The present findings are consistent with a triple origin of the sphincter iris in the chick embryo. This muscle is derived from the inner epithelium of the pupillary margin, the intermediate region of the outer epithelium, and from the mesenchymal cells. The cells of the inner epithelium of the pupillary margin are differentiated into smooth muscle cells, and the remaining cells form striated muscle cells.

Morphological studies of the developing human esophageal epithelium.

This article focusses on the structural development of human esophageal ciliated epithelium. A combination of transmission electron microscopic (TEM), scanning electron microscopic (SEM), radioautographic, and light microscopic (LM) analyses were carried out using intact fetal tissues between 8 and 20 weeks of gestation as well as cultured esophageal explants. Up to the age of 10 weeks, the stratified esophageal epithelium consisted of two longitudinal primary folds. The surface cells were undifferentiated and contained large glycogen aggregates. Between 11 and 16 weeks, the primary folds (now up to four) had developed secondary folds. The thickness of the epithelium drastically increased (123%) in concomittance with a differentiation of surface columnar ciliated cells. These highly specialized surface cells exhibited junctional complexes and well-developed organelles with numerous microvilli interspersed among the cilia. Transverse sections revealed the internal structure of the cilia with a consistent pattern of nine doublet microtubules surrounding a central pair of single microtubules. Freeze-fracture studies illustrated the presence of a ciliary necklace composed of 6 ring-like rows of intramembranous particles. They also revealed the structure of ciliary cell tight junctions consisting of up to nine anastomosing strands (P-face) or complementary grooves (E-face). Ultrastructural studies (LM, TEM, SEM) of the esophageal squamous epithelium obtained after 15 days of culture showed that the newly formed epithelium was similar to adult human epithelium. Finally LM and SEM observations established that the esophagogastric junction was not yet well delineated, consisting of a transitional area composed of a mixture of esophageal ciliated cells and gastric columnar mucous cells.

[Histological and histochemical studies on the detection of the esogaster in the agastric cyprinidae Aristichthys nobilis Rich. (Marble carp)]. / Histologische und histochemische Untersuchungen zum Nachweis des Oesogasters bei dem magenlosen Cypriniden Aristichthys nobilis Rich. (Marmorkarpfen).

In postnatal Aristichthys nobilis Rich. oesogaster was proved by histological and histochemical methods. During the larval development oesogaster becomes reduced completely in cranial direction. The statement is demonstrating the secondary character of lost stomach in phylogeny of this fish species.