Investigation of the intra-abdominal oesophagus and hiatus in fetal rats with oesophageal atresia and tracheo-oesophageal fistula

Contractile profile of esophageal and gastric fundus strips in experimental doxorubicin-induced esophageal atresia

Esophageal atresia (EA) is characterized by esophageal and gastric motility changes secondary to developmental and postsurgical damage. This study evaluated the in vitro contractile profile of the distal esophagus and gastric fundus in an experimental model of EA induced by doxorubicin (DOXO). Wistar pregnant rats received DOXO 2.2 mg/kg on the 8th and 9th gestational days. On day 21.5, fetuses were collected, sacrificed, and divided into groups: control, DOXO without EA (DOXO-EA), and DOXO with EA (DOXO+EA). Strips from the distal esophagus and gastric fundus were mounted on a wire myograph and isolated organ-bath system, respectively, and subjected to increasing concentrations of carbamylcholine chloride (carbachol, CCh). The isolated esophagus was also stimulated with increasing concentrations of KCl. In esophagus, the concentration-effect curves were reduced in response to CCh in the DOXO+EA and DOXO-EA groups compared to the control group (P<0.05). The maximum effect values (E_max) for DOXO+EA and DOXO-EA were significantly lower than control (P<0.05), but the half-maximal effective concentration (EC₅₀) values were not significantly different when the three groups were compared (P>0.05). In response to KCl, the distal esophagus samples in the three groups were not statistically different with regard to E_max or EC₅₀ values (P>0.05). No significant difference was noted for EC₅₀ or E_max values in fundic strips stimulated with CCh (P>0.05). In conclusion, exposure of dams to DOXO during gestation inhibited the contractile behavior of esophageal strips from offspring in response to CCh but not KCl, regardless of EA induction. The gastric fundus of DOXO-exposed offspring did not have altered contractile responsiveness to cholinergic stimulation.

Current Controversies in the Surgical Treatment of Esophageal Atresia

Background and Aims:

Esophageal atresia (EA) with or without tracheo-esophageal fistula (TEF) is a rare condition that can be nowadays succesfully treated. The current interest therefore is focused on the management of the difficult cases, on thoracoscopic approach, and on some aspects of the long-term results.

Methods:

The current strategies for the difficult or impossible anastomoses in pure and long-gap EA, the introduction of thoracoscopic repair and the causes, mechanisms and management of post-operative gastro-esophageal reflux (GER) are reviewed.

Results:

Methods of esophageal elongation and multi-staged repair of pure and long-gap EA allow anastomosis but with functional results that are often poor. Esophageal replacement with colon or stomach achieves at least similar results and often requires less procedures. Thoracoscopic repair is a promising adjunct, but the difficulties for setting it as a gold-standard are pointed out. GER is a part of the disease and its surgical treatment, that is often required, is burdened by high failure rates.

Conclusions:

EA with or without TEF can be successfully treated in most cases, but a number of unsolved issues remain and the current approach to difficult cases will certainly evolve in the future.

Gastric smooth muscle contractility changes in the esophageal atresia rat model: an in vitro study

PURPOSE

The aim of the study was to investigate the gastric smooth muscle reactivity in the Adriamycin-induced esophageal atresia (EA) rat model.

METHODS

The fetuses were divided into 3 groups. The control group was exposed to saline. The second group was comprised of fetuses that were exposed to Adriamycin but did not have EA (Adriamycin-no-EA group). The third group was comprised of fetuses that were exposed to Adriamycin and had EA (Adriamycin-EA group). Gastric fundus strips were studied in vitro for their contractile response to receptor activation in the 3 groups.

RESULTS

Contractile responses of gastric smooth muscle to carbachol and KCl were increased in the Adriamycin-EA group compared with the Adriamycin-no-EA group. Also serotonin-induced contractile response in the Adriamycin-EA group decreased compared with the Adriamycin-no-EA group. Relaxation of gastric smooth muscle strips to isoproterenol was comparably unaffected in the Adriamycin-EA and Adriamycin-no-EA groups. Likewise, no change in the response to agonist studies was observed between the control and Adriamycin-no-EA groups. The relaxant response to papaverine was not different in the 3 groups.

CONCLUSIONS

This study found changes of receptor-dependent and receptor-independent contraction of the gastric fundus smooth muscle in the fetuses with EA. Therefore, impaired contractile responses may be, at least in part, a contributing factor in the abnormal gastric motility seen in EA.