Selective inhibition of nitric oxide synthase causes increased muscle thickness in rat esophagus

Combination of Symptom Profile, Endoscopic Findings, and Esophageal Mucosal Histopathology Helps to Differentiate Achalasia from Refractory Gastroesophageal Reflux Disease

Achalasia, a rare primary esophageal motility disorder, is often misdiagnosed as refractory gastroesophageal reflux disease (GERD). This study is aimed to identify the clinical and histopathologic features that may help to differentiate these two entities. Patients with untreated achalasia and those with refractory reflux symptoms despite ≥8 weeks of proton-pump inhibitor treatment were enrolled prospectively. All patients underwent validated symptom questionnaires, esophagogastroduodenoscopy with biopsy, and high-resolution impedance manometry (HRIM). Histopathology of esophageal mucosa was compared based on four pre-determined histological criteria: basal cell hyperplasia or papillae elongation, eosinophilic infiltration, petechiae formation, and hypertrophy of the muscularis mucosae (MM). Compared with the GERD patients, patients with achalasia had similar reflux symptoms, but higher Eckardt scores, fewer erosive esophagitis and hiatal hernia, more esophageal food retention on endoscopy, and higher prevalence of hypertrophy of the MM and petechiae formation on histopathology. Multivariate logistic regression based on Eckardt score ≥4, normal esophagogastric junction morphology or esophageal food retention, and coexistence of petechiae formation and hypertrophy of the MM, established the best prediction model for achalasia. Therefore, combination of routinely accessible variables, including Eckardt score, endoscopic features, and histopathology obtained via esophageal mucosal biopsy, may provide an earlier identification of achalasia.

Neurochemical characterization of intramural nerve fibres in the porcine oesophagus

The gastrointestinal (GI) tract is innervated by nerve processes derived from the intramural enteric neurons and neurons localized outside the digestive tract. This study analysed the neurochemical characterization of nerves in the wall of the porcine oesophagus using single immunofluorescence technique. Immunoreactivity to vesicular acetylcholine transporter (VAChT), neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), somatostatin (SOM), galanin (GAL), neuronal isoform of nitric oxide synthase (nNOS), substance P (SP), leucine enkephalin (LENK), calcitonin gene-related peptide (CGRP) or dopamine beta-hydroxylase (DBH) was investigated in intramuscular and intramucosal nerves of the cervical, thoracic and abdominal oesophagus. The results indicate that all of the substances studied were present in the oesophageal nerves. The density of particular populations of fibres depended on the segment of the oesophagus. The most numerous were fibres immunoreactive to VIP in the longitudinal and circular muscle layers of the abdominal oesophagus: The number of these fibres amounted to 16.4 ± 0.8 and 18.1 ± 3.1, respectively. In turn, the least numerous were CGRP-positive fibres, which were present only in the circular muscle layer of the cervical oesophagus and mucosal layer of the abdominal oesophagus in the number of 0.3 ± 0. The obtained results show that nerves in the porcine oesophageal wall are very diverse in their neurochemical coding, and differences between particular parts of the oesophagus suggest that organization of the innervation clearly depends on the fragment of this organ.

Clinical significance of interleukin‑6 and inducible nitric oxide synthase in ketamine‑induced cystitis

Ketamine is an ionotropic glutamatergic N-methyl-D-aspartate receptor antagonist, which is widely used among recreational drug abusers. Ketamine abusers exhibit substantially reduced bladder capacity, which can lead to urinary frequency. The molecular pathogenesis of ketamine-induced cystitis has been scarcely reported. Given previous clinical findings, it may be hypothesized that pathological alterations in smooth muscle cells (SMCs) of the urinary bladder serve a crucial role in the mechanism underlying cystitis. In the present study, two lineages of SMCs, one from differentiated foreskin-derived fibroblast-like stromal cells and the other from cultured normal aortic SMCs, were used to study ketamine-induced molecular alterations. Polymerase chain reaction was used to study the effects of ketamine on oxidative stress. The effects of adjuvant chemo-therapy with cyclophosphamide (CTX) were also investigated. The results indicated that the expression levels of interleukin-6 and inducible nitric oxide synthase (iNOS) were decreased, whereas collagen expression and deposition were increased in ketamine-treated SMCs. Conversely, treatment with CTX restored the expression of iNOS, which may prevent or limit oxidative damage. In conclusion, the present study demonstrated that ketamine may induce several molecular alterations in SMCs and these changes may be associated with the clinical symptoms observed in ketamine abusers. In addition, the specific chemotherapeutic agent CTX may reverse these ketamine-induced aberrations.