The etiology of achalasia: An immune-dominant disease

Development and Validation of Serum Markers as Noninvasive Diagnostic Methods for Achalasia

INTRODUCTION

Currently, the diagnosis of achalasia mainly relies on invasive or radioactive examinations. This study aimed to develop a noninvasive diagnostic method for achalasia based on specific serum markers.

METHODS

Serum levels of profilin-1, galectin-10, immunoglobulin heavy variable 3-9, vasodilator-stimulated phosphoprotein, and transgelin-2 were measured in patients with achalasia and controls by enzyme-linked immunosorbent assay. The diagnostic values and thresholds were determined by the receiver operating characteristic curve analysis. Then, patients with dysphagia were prospectively enrolled to validate the ability of these molecules for achalasia diagnosing.

RESULTS

A total of 142 patients with achalasia and 50 nonachalasia controls (healthy volunteers and patients with reflux esophagitis) were retrospectively included. The serum levels of profilin-1, galectin-10, and transgelin-2 in patients with achalasia were significantly higher than those in healthy volunteers and patients with reflux esophagitis ( P all < 0.001). Profilin-1, galectin-10, and transgelin-2 were of good performance in diagnosing achalasia, with optimal thresholds of 2,171.2, 33.9, and 1,630.6 pg/mL, respectively. Second, 40 patients with dysphagia were prospectively enrolled to the validation of achalasia. For profilin-1, the positive predictive value, negative predictive value, sensitivity, and specificity were 100.0%, 64.5%, 45.0%, and 100.0%, respectively. The figures for transgelin-2 were 65.5%, 90.9%, 95.0%, and 50.0%. When both increased, the positive predictive value reached to 100.0%. When both indexes were normal, the negative predictive value was 100.0%.

DISCUSSION

Profilin-1 and transgelin-2 were promising biomarkers for achalasia diagnosis and performed better in combination. Further multicenter studies are necessary to verify their application as preliminary screening tools for achalasia.

MANAGEMENT OF SYMPTOMS RECURRENCE AFTER MYOTOMY FOR ACHALASIA. A PRACTICAL APPROACH

BACKGROUND

Achalasia is an esophageal motility disorder, and myotomy is one of the most used treatment techniques. However, symptom persistence or recurrence occurs in 9 to 20% of cases.

AIMS

This study aims to provide a practical approach for managing the recurrence or persistence of achalasia symptoms after myotomy.

METHODS

A critical review was performed to gather evidence for a rational approach for managing the recurrence or persistence of achalasia symptoms after myotomy.

RESULTS

To properly manage an achalasia patient with significant symptoms after myotomy, such as dysphagia, regurgitation, thoracic pain, and weight loss, it is necessary to classify symptoms, stratify severity, perform appropriate tests, and define a treatment strategy. A systematic differential diagnosis workup is essential to cover the main etiologies of symptoms recurrence or persistence after myotomy. Upper digestive endoscopy and dynamic digital radiography are the main tests that can be applied for investigation. The treatment options include endoscopic dilation, peroral endoscopic myotomy, redo surgery, and esophagectomy, and the decision should be based on the patient's individual characteristics.

CONCLUSIONS

A good clinical evaluation and the use of proper tests jointly with a rational assessment, are essential for the management of symptoms recurrence or persistence after achalasia myotomy.

Evaluating the molecular and genetic mechanisms underlying gut motility disorders

INTRODUCTION

Gastrointestinal (GI) motility disorders comprise a wide range of different diseases affecting the structural or functional integrity of the GI neuromusculature. Their clinical presentation and burden of disease depends on the predominant location and extent of gut involvement as well as the component of the gut neuromusculature affected.

AREAS COVERED

A comprehensive literature review was conducted using the PubMed and Medline databases to identify articles related to GI motility and functional disorders, published between 2016 and 2023. In this article, we highlight the current knowledge of molecular and genetic mechanisms underlying GI dysmotility, including disorders of gut-brain interaction, which involve both GI motor and sensory disturbance.

EXPERT OPINION

Although the pathophysiology and molecular mechanisms underlying many such disorders remain unclear, recent advances in the assessment of intestinal tissue samples, genetic testing with the application of 'omics' technologies and the use of animal models will provide better insights into disease pathogenesis as well as opportunities to improve therapy.

The molecular pathogenesis of achalasia: a paired lower esophageal sphincter muscle and serum 4D label-free proteomic study

Background

Achalasia is a primary esophageal motility disorder with potential molecular pathogenesis remaining uncertain. This study aimed to identify the differentially expressed proteins and potential pathways among achalasia subtypes and controls to further reveal the molecular pathogenesis of achalasia.

Methods

Paired lower esophageal sphincter (LES) muscle and serum samples from 24 achalasia patients were collected. We also collected 10 normal serum samples from healthy controls and 10 normal LES muscle samples from esophageal cancer patients. The 4D label-free proteomic analysis was performed to identify the potential proteins and pathways involved in achalasia.

Results

Analysis of Similarities showed distinct proteomic patterns of serum and muscle samples between achalasia patients and controls (both P < 0.05). Functional enrichment analysis suggested that these differentially expressed proteins were immunity-, infection-, inflammation-, and neurodegeneration-associated. The mfuzz analysis in LES specimens showed that proteins involved in the extracellular matrix-receptor interaction increased sequentially between the control group, type III, type II, and type I achalasia. Only 26 proteins altered in the same directions in serum and muscle samples.

Conclusions

This first 4D label-free proteomic study of achalasia indicated that there were specific protein alterations in both the serum and muscle of achalasia, involving immunity, inflammation, infection, and neurodegeneration pathways. Distinct protein clusters between types I, II, and III revealed the potential molecular pathways associated with different disease stages. Analysis of proteins changed in both muscle and serum samples highlighted the importance of further studies on LES muscle and revealed potential autoantibodies.

Achalasia, from diagnosis to treatment

INTRODUCTION

Achalasia is an uncommon esophageal motility disorder and is characterized by alterations of the motility of the esophageal body in conjunction with altered lower esophageal sphincter (LES) relaxation. The clinical presentation of patients with achalasia may be complex; however, the most frequent symptom is dysphagia. The management of patients with achalasia is often challenging, due to the heterogeneous clinical presentation.

AREAS COVERED

The diagnosis and management of achalasia has significantly improved in the last years due to the growing availability of high-resolution manometry (HRM) and the implementation in the therapeutic armamentarium of new therapeutic endoscopic procedures. Traditional therapeutic strategies include botulinum toxin injected to the LES and pneumatic balloon dilation. On the other hand, surgical treatments contemplate laparoscopic Heller myotomy and, less frequently, esophagectomy. Furthermore, in the last few years, per oral endoscopic myotomy (POEM) has been proposed as the main endoscopic therapeutic alternative to the laparoscopic Heller myotomy.

EXPERT OPINION

Diagnosis and treatment of achalasia still represent a challenging area. However, we believe that an accurate up-front evaluation is, nowadays, necessary in addressing patients with achalasia for a more accurate diagnosis as well as for the best treatment options.

A cross-sectional study reveals a chronic low-grade inflammation in achalasia

BACKGROUND AND AIM

Immune-mediated neuroinflammation has been proposed to underlie the loss of lower esophageal sphincter (LES) myenteric neurons in achalasia. However, the immune status and key pathogenic immune subpopulations remain unclear. This study aims to evaluate the inflammatory status of patients with achalasia and their correlation with clinical characteristics, and further explore the key pathogenic subpopulations.

METHODS

We investigated the complete blood cell count and inflammatory markers in a large population of patients with achalasia (n = 341) and healthy controls (n = 80). The subpopulations of lymphocytes were analyzed by flow cytometry. Immunofluorescence was used to determine immune cell infiltration in the LES. Transcriptome changes of the key subpopulation were determined by RNA sequencing analysis.

RESULTS

NLR, MLR, CRP, globulin, IL-6 and IL-10 were significantly elevated in patients with achalasia. MLR and globulin were positively correlated with disease duration. The absolute count and percentage of CD8+ T cells in peripheral blood and its infiltration around ganglion in the LES were significantly increased in achalasia. Transcriptome analysis indicated that CD8+ T cells were activated and proliferative. In addition to multiple inflammatory pathways, regulation of neuroinflammatory response pathway was also significantly up-regulated in achalasia. GSEA analysis revealed a close association with autoimmune diseases.

CONCLUSIONS

Patients with achalasia suffered from chronic low-grade inflammation with dysregulated immune cells and mediators associated with disease duration. CD8+ T cells might be the key pathogenic subpopulation of achalasia. Our results provide an important immune cell signature of the pathogenesis of achalasia.

RNA-sequencing reveals molecular and regional differences in the esophageal mucosa of achalasia patients

Achalasia is an esophageal motility disorder characterized by the functional loss of myenteric plexus ganglion cells in the distal esophagus and lower esophageal sphincter. Histological changes have been reported in the esophageal mucosa of achalasia, suggesting its involvement in disease pathogenesis. Despite recent advances in diagnosis, our understanding of achalasia pathogenesis at the molecular level is very limited and gene expression profiling has not been performed. We performed bulk RNA-sequencing on esophageal mucosa from 14 achalasia and 8 healthy subjects. 65 differentially expressed genes (DEGs) were found in the distal esophageal mucosa of achalasia subjects and 120 DEGs were identified in proximal esophagus. Gene expression analysis identified genes common or exclusive to proximal and distal esophagus, highlighting regional differences in the disease. Enrichment of signaling pathways related to cytokine response and viral defense were observed. Increased infiltration of CD45+ intraepithelial leukocytes were seen in the mucosa of 38 achalasia patients compared to 12 controls. Novel insights into the molecular changes occurring in achalasia were generated in this transcriptomic study. Some gene changes observed in the mucosa of achalasia may be associated with esophagitis. Differences in DEGs between distal and proximal esophagus highlight the importance of better understanding regional differences in achalasia.

Autoimmune and viral risk factors are associated with achalasia: A case-control study

BACKGROUND

Achalasia is a rare esophageal motility disorder of uncertain etiology. While past studies have indicated that autoimmune conditions and viral infections may be associated with development of achalasia, these associations are yet to be examined in large, population-based studies.

METHODS

A matched case-control study was performed using administrative claim data from the IBM MarketScan Commercial Claims and Encounters Database between 2000 and 2019. A history of selected autoimmune conditions and viral infections was assessed using past medical claims. Multivariable conditional logistic regression was used to account for the matched nature of the study design and further control for confounding by demographic and clinical characteristics when reporting adjusted odds ratios (aORs).

KEY RESULTS

Among 6769 cases and 27,076 controls, presence of any of the autoimmune conditions studied was associated with increased odds of achalasia (aOR = 1.26, 95% CI: 1.11, 1.42). Scleroderma or systemic sclerosis (aOR = 8.13, 95% CI: 3.34, 19.80) and Addison's disease (aOR = 3.83, 95% CI: 1.83, 8.04) had the strongest associations with achalasia. Presence of any of the viral infections studied was also associated with an increased risk of achalasia (aOR = 1.58, 95% CI: 1.23, 2.01). Varicella zoster virus (aOR = 3.84, 95% CI: 1.94, 7.62) and human papillomavirus (aOR = 1.77, 95% CI: 1.15, 2.73) both had strong relationships with achalasia.

CONCLUSIONS AND INFERENCES

These findings suggest that achalasia may have autoimmune and viral components contributing to its etiology. Future mechanistic studies could target specific diseases and agents highlighted by this research.

Achalasia

Achalasia is a rare disorder of the oesophageal smooth muscle characterized by impaired relaxation of the lower oesophageal sphincter (LES) and absent or spastic contractions in the oesophageal body. The key pathophysiological mechanism is loss of inhibitory nerve function that probably results from an autoimmune attack targeting oesophageal myenteric nerves through cell-mediated and, possibly, antibody-mediated mechanisms. Achalasia incidence and prevalence increase with age, but the disorder can affect all ages and both sexes. Cardinal symptoms consist of dysphagia, regurgitation, chest pain and weight loss. Several years can pass between symptom onset and an achalasia diagnosis. Evaluation starts with endoscopy to rule out structural causes, followed by high-resolution manometry and/or barium radiography. Functional lumen imaging probe can provide complementary evidence. Achalasia subtypes have management and prognostic implications. Although symptom questionnaires are not useful for diagnosis, the Eckardt score is a simple symptom scoring scale that helps to quantify symptom response to therapy. Oral pharmacotherapy is not particularly effective. Botulinum toxin injection into the LES can temporize symptoms and function as a bridge to definitive therapy. Pneumatic dilation, per-oral endoscopic myotomy and laparoscopic Heller myotomy can provide durable symptom benefit. End-stage achalasia with a dilated, non-functioning oesophagus may require oesophagectomy or enteral feeding into the stomach. Long-term complications can, rarely, include oesophageal cancer, but surveillance recommendations have not been established.

Diagnosis and Management of Achalasia: Updates of the Last Two Years

Achalasia is a rare neurodegenerative disorder causing dysphagia and is characterized by abnormal esophageal motor function as well as the loss of lower esophageal sphincter (LES) relaxation. The assessment and management of achalasia has significantly progressed in recent years due to the advances in high-resolution manometry (HRM) technology along with the improvements and innovations of therapeutic endoscopy procedures. The recent evolution of HRM technology with the inclusion of an adjunctive test, fluoroscopy, and EndoFLIP has enabled more precise diagnoses of achalasia to be made and the subgrouping into therapeutically meaningful subtypes. Current management possibilities include endoscopic treatments such as Botulinum toxin injected to the LES and pneumatic balloon dilation. Surgical treatment includes laparoscopic Heller myotomy and esophagectomy. Furthermore, in recent years, per oral endoscopic myotomy (POEM) has established itself as a principal endoscopic therapeutic alternative to the traditional laparoscopic Heller myotomy. The latest randomized trials report that POEM, pneumatic balloon dilatation, and laparoscopic Heller's myotomy have comparable effectiveness and complications rates. The aim of the current review is to provide a practical clinical approach to dysphagia and to shed light on the most recent improvements in diagnostics and treatment of achalasia over the last two years.