Anatomy and physiology of the esophagus

A Window for Enhanced Oral Delivery of Therapeutics via Lipid Nanoparticles

Oral administration of dosage forms is convenient and beneficial in several respects. Lipid nanoparticulate dosage forms have emerged as a useful carrier system in deploying low solubility drugs systemically, particularly class II, III, and IV drugs of the Biopharmaceutics Classification System. Like other nanoparticulate delivery systems, their low size-to-volume ratio facilitates uptake by phagocytosis. Lipid nanoparticles also provide scope for high drug loading and extended-release capability, ensuring diminished systemic side effects and improved pharmacokinetics. However, rapid gastrointestinal (GI) clearance of particulate delivery systems impedes efficient uptake across the mucosa. Mucoadhesion of dosage forms to the GI mucosa results in longer transit times due to interactions between the former and mucus. Delayed transit times facilitate transfer of the dosage form across the mucosa. In this regard, a balance between mucoadhesion and mucopenetration guarantees optimal systemic transfer. Furthermore, the interplay between GI anatomy and physiology is key to ensuring efficient systemic uptake. This review captures salient anatomical and physiological features of the GI tract and how these can be exploited for maximal systemic delivery of lipid nanoparticles. Materials used to impart mucoadhesion and examples of successful mucoadhesive lipid nanoformulations are highlighted in this review.

Dietary and Nutritional Support in Gastrointestinal Diseases of the Upper Gastrointestinal Tract (I): Esophagus

The esophagus is the centerpiece of the digestive system of individuals and plays an essential role in transporting swallowed nutrients to the stomach. Diseases of the esophagus can alter this mechanism either by causing anatomical damage that obstructs the lumen of the organ (e.g., peptic, or eosinophilic stricture) or by generating severe motility disorders that impair the progression of the alimentary bolus (e.g., severe dysphagia of neurological origin or achalasia). In all cases, nutrient assimilation may be compromised. In some cases (e.g., ingestion of corrosive agents), a hypercatabolic state is generated, which increases resting energy expenditure. This manuscript reviews current clinical guidelines on the dietary and nutritional management of esophageal disorders such as severe oropharyngeal dysphagia, achalasia, eosinophilic esophagitis, lesions by caustics, and gastroesophageal reflux disease and its complications (Barrett's esophagus and adenocarcinoma). The importance of nutritional support in improving outcomes is also highlighted.

Successful Management of Esophageal Perforation by Intraoperative Microscopy and Esophagoscopic Assistance: A Case Report

Surgical repair of esophageal perforation is a challenging procedure with a high risk of secondary complications, such as early esophageal leakage and late esophageal stricture, which can significantly reduce the patient's quality of life. A 34-year-old man underwent anterior cervical corpectomy decompression and fusion. On the ninth day post-operation, the patient developed fever and neck swelling. A computed tomography scan of the neck showed multiple subcutaneous pneumatosis. An esophageal perforation of approximately 1.5 cm in diameter was identified by esophagoscopy. During the operation, the fistula was first located using an esophagoscope. The distal end of the esophagoscope was then placed into the stomach to support the damaged segment of the esophagus. The esophageal mucosa was sutured under the microscope, and the perforation was successfully repaired. Postoperatively, the patient's body temperature decreased, and the infection indexes gradually returned to normal. Three months after the operation, the esophagoscopic review showed complete healing of the perforation. Esophagoscopy plays an important role in diagnosing and repairing esophageal perforations. The esophagoscope provides direct visualization of the perforation during diagnosis and detects smaller and not yet fully penetrated esophageal injuries. During the repair process, the esophagoscope immobilizes the esophagus, prevents its movement and facilitates suturing, maintains proper dilatation of the esophagus, provides space for suturing, and prevents esophageal stricture.

Experimental investigations of the human oesophagus: anisotropic properties of the embalmed muscular layer under large deformation

The oesophagus is a primarily mechanical organ whose material characterisation would aid in the investigation of its pathophysiology, help in the field of tissue engineering, and improve surgical simulations and the design of medical devices. However, the layer-dependent, anisotropic properties of the organ have not been investigated using human tissue, particularly in regard to its viscoelastic and stress-softening behaviour. Restrictions caused by the COVID-19 pandemic meant that fresh human tissue was not available for dissection. Therefore, in this study, the layer-specific material properties of the human oesophagus were investigated through ex vivo experimentation of the embalmed muscularis propria layer. For this, a series of uniaxial tension cyclic tests with increasing stretch levels were conducted at two different strain rates. The muscular layers from three different cadaveric specimens were tested in both the longitudinal and circumferential directions. The results displayed highly nonlinear and anisotropic behaviour, with both time- and history-dependent stress-softening. The longitudinal direction was found to be stiffer than the circumferential direction at both strain rates. Strain rate-dependent behaviour was apparent, with an increase in strain rate resulting in an increase in stiffness in both directions. Histological analysis was carried out via various staining methods; the results of which were discussed with regard to the experimentally observed stress-stretch response. Finally, the behaviour of the muscularis propria was simulated using a matrix-fibre model able to capture the various mechanical phenomena exhibited, the fibre orientation of which was driven by the histological findings of the study.

Clinicopathologic Features and Clinical Outcomes of Esophageal Gastrointestinal Stromal Tumor: Evaluation of a Pooled Case Series

Clinicopathologic features and clinical outcomes of gastrointestinal stromal tumors (GISTs) in esophagus are limited, because of the relatively rare incidence of esophageal GISTs. Therefore, the aim of the current study was to investigate the clinicopathologic features and clinical outcomes of esophageal GISTs, and to investigate the potential factors that may predict prognosis.Esophageal GIST cases were obtained from our center and from case reports and clinical studies extracted from MEDLINE. Clinicopathologic features and survivals were analyzed and compared with gastric GISTs from our center.The most common location was lower esophagus (86.84%), followed by middle and upper esophagus (11.40% and 1.76%). The majority of esophageal GISTs were classified as high-risk category (70.83%). Mitotic index was correlated with histologic type, mutational status, and tumor size. The 5-year disease-free survival and disease-specific survival were 65.1% and 65.9%, respectively. Tumor size, mitotic index, and National Institutes of Health risk classification were associated with prognosis of esophageal GISTs. Only tumor size, however, was the independent risk factor for the prognosis of esophageal GISTs. In comparison to gastric GISTs, the distribution of tumor size, histologic type, and National Institutes of Health risk classification were significantly different between esophageal GISTs and gastric GISTs. The disease-free survival and disease-specific survival of esophageal GISTs were significantly lower than that of gastric GISTs.The most common location for esophageal GISTs was lower esophagus, and most of the esophageal GISTs are high-risk category. Tumor size was the independent risk factor for the prognosis of esophageal GISTs. Esophageal GISTs differ significantly from gastric GISTs in respect to clinicopathologic features. The prognosis of esophageal GISTs was worse than that of gastric GISTs.

Perianesthesia care of the patient with gastroesophageal reflux disease

Every day millions of people suffer heartburn and other related symptoms of gastroesophageal reflux disease (GERD). Because symptoms can lead to a reduced quality of life, GERD sufferers are desperate for relief. This article explores the definition and pathophysiology, clinical manifestations, diagnostic procedures, and treatment options for GERD, including lifestyle modifications, medications, surgery, and alternative procedures. It also discusses preoperative, anesthesia/intraoperative, and postoperative special care considerations for the surgical patient with GERD.

Mucosal tissue injury in cancer therapy. More than muscositis and mouthwash

PURPOSE

The purpose of this article is as follows: 1) to describe the characteristics and scope of mucosal tissue injury associated with cancer treatment; 2) to discuss recent advances in related basic and clinical science; and 3) to articulate research needs and opportunities to be addressed through collaborative interdisciplinary research.

OVERVIEW

Mucosal tissue injury is both a direct and indirect consequence of cancer therapy, with manifestations that include damage and a number of other potentially serious sequelae. Current research in mucosal tissue injury is focused on the biology, immunology, and genetics of mucosal injury; clinical problems; assessment and management; and processes and outcomes of care.

CLINICAL IMPLICATIONS

Results from these various areas of research enhance the understanding of the mechanisms of mucosal tissue injury, provide direction for the development of policy and for clinical practice, and help to define research needs and opportunities. Future research on the complex process of mucosal tissue injury will be interdisciplinary and will cross the boundaries among basic, translational, and clinical science.

Biology of oral mucosa and esophagus

The mucosal lining of the oral cavity and esophagus functions to protect the underlying tissue from mechanical damage and from the entry of microorganisms and toxic materials that may be present in the oropharynx. In different regions, the mucosa shows adaptation to differing mechanical demands: Masticatory mucosa consists of a stratified squamous keratinized epithelium tightly attached to the underlying tissues by a collagenous connective tissue, whereas lining mucosa comprises a nonkeratinized epithelium supported by a more elastic and flexible connective tissue. The epithelium is constantly replaced by cell division in the deeper layers, and turnover is faster in the lining than in the masticatory regions. Chemotherapeutic agents and radiation limit proliferation of the epithelium so that it becomes thin or ulcerated; this will first occur in the lining regions. The principal patterns of epithelial differentiation are represented by keratinization and nonkeratinization. As keratinocytes enter into differentiation, they become larger and begin to flatten and to accumulate cytokeratin filaments. In addition to the keratins, the differentiating keratinocytes synthesize and retain a number of specific proteins, including profilaggrin, involucrin, and other precursors of the thickening of the cell envelope in the most superficial layers. The concept of epithelial homeostasis implies that cell production in the deeper layers will be balanced by loss of cells from the surface. There is a rapid clearance of surface cells, which acts as a protective mechanism by limiting colonization and invasion of microorganisms adherent to the mucosal surface.