Morphofunctional analysis of experimental model of esophageal achalasia in rats

Docking Proteins Upregulate IL-1β Expression in Lower Esophageal Sphincter Muscle in Esophageal Achalasia

Background/Objectives: Esophageal achalasia is an archetypal esophageal motility disorder characterized by abnormal peristalsis of the esophageal body and impaired lower esophageal sphincter (LES) relaxation. Methods: In this study, the mRNA expression of docking proteins 1 and 2 (DOK1 and DOK2, respectively) were analyzed and the mechanisms underlying achalasia onset were investigated. Results:DOK1 and DOK2 mRNA levels significantly increased in the LES of patients with achalasia. Moreover, significant correlations were observed between IL-1β and DOK1, IL-1β and DOK2, ATG16L1 and DOK1, and HSV1-miR-H1-3p and DOK2 expression levels. However, a correlation between ATG16L1 and DOK2 or between HSV-miR-H1-3p and DOK1 expression was not observed. In addition, a positive correlation was observed between patient age and DOK1 expression. Microarray analysis revealed a significant decrease in the expression of hsa-miR-377-3p and miR-376a-3p in the LES muscle of patients with achalasia. Conclusions: These miRNAs possessed sequences targeting DOK. The upregulation of DOK1 and DOK2 expression induces IL-1β expression in the LES of achalasia patients, which may contribute to the development of esophageal motility disorder.

Poly(lactic acid)-hyperbranched polyglycerol nanoparticles enhance bioadhesive treatment of esophageal disease and reduce systemic drug exposure

The effective treatment of esophageal disease represents a significant unmet clinical need, as existing treatments often lead to unnecessary systemic drug exposure and suboptimal concentrations at the disease site. Here, surface-modified bioadhesive poly(lactic acid)-hyperbranched polyglycerol nanoparticles (BNPs), with an average 100-200 nm diameter, were developed for local and sustained esophageal drug delivery. BNPs showed significantly higher adhesion and permeation into ex vivo human and rat esophageal tissue than non-adhesive nanoparticles (NNPs) and had longer residence times within the rat esophagus in vivo. Incubation with human esophagus (Het-1A) cells confirmed BNPs' biocompatibility at clinically relevant concentrations. In a rat model of achalasia, nifedipine-loaded BNPs significantly enhanced esophageal drug exposure, increased therapeutic efficacy, and reduced systemic drug exposure compared to NNPs and free drug. The safety of BNPs was demonstrated by an absence of intestinal, hepatic, and splenic toxicity following administration. This study is the first to demonstrate the efficacy of BNPs for esophageal drug delivery and highlight their potential for improving the lives of patients suffering with esophageal conditions.

Megaesophagus in a line of transgenic rats: a model of achalasia

Megaesophagus is defined as the abnormal enlargement or dilatation of the esophagus, characterized by a lack of normal contraction of the esophageal walls. This is called achalasia when associated with reduced or no relaxation of the lower esophageal sphincter (LES). To date, there are few naturally occurring models for this disease. A colony of transgenic (Pvrl3-Cre) rats presented with megaesophagus at 3 to 4 months of age; further breeding studies revealed a prevalence of 90% of transgene-positive animals having megaesophagus. Affected rats could be maintained on a total liquid diet long term and were shown to display the classic features of dilated esophagus, closed lower esophageal sphincter, and abnormal contractions on contrast radiography and fluoroscopy. Histologically, the findings of muscle degeneration, inflammation, and a reduced number of myenteric ganglia in the esophagus combined with ultrastructural lesions of muscle fiber disarray and mitochondrial changes in the striated muscle of these animals closely mimic that seen in the human condition. Muscle contractile studies looking at the response of the lower esophageal sphincter and fundus to electrical field stimulation, sodium nitroprusside, and L-nitro-L-arginine methyl ester also demonstrate the similarity between megaesophagus in the transgenic rats and patients with achalasia. No primary cause for megaesophagus was found, but the close parallel to the human form of the disease, as well as ease of care and manipulation of these rats, makes this a suitable model to better understand the etiology of achalasia as well as study new management and treatment options for this incurable condition.