An increased proportion of inflammatory cells express tumor necrosis factor alpha in idiopathic achalasia of the esophagus

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.

Eosinophils Infiltration in Esophageal Muscularis Propria Induces Achalasia-like Esophageal Motility Disorder in Mice

Eosinophil infiltration in esophageal muscularis propria is common in achalasia (AC). This study aims to evaluate the effect of eosinophil infiltration in muscularis propria of the esophagus on esophageal motility in mice. A mouse model with eosinophil infiltration in the esophageal muscle layer was established by long term Ovalbumin (OVA) exposure. The histopathology features of esophageal muscularis propria as well as parameters of esophageal motility, such as lower esophageal sphincter pressure (LESP) and esophageal emptying, were compared between model and control group. In addition, the histopathology and motility of esophagus at each time point in the model group were compared. The esophageal motor function severely deteriorated in the model group, mimicking the abnormal esophageal motility of AC, with more eosinophils and fewer SOX-10-IR cells in esophageal muscularis propria in the model group, compared with control. With the prolongation of OVA treatment, esophageal motility disorder was aggravated, accompanied by increased eosinophils in the the muscle layer of esophagus and decreased SOX-10-IR cells in the model group. In addition, the eosinophil count was negatively correlated with SOX-10-IR cells. Long-term exposure to OVA assisted by alum may induce eosinophil infiltration in esophageal muscularis propria, reduced SOX-10-IR cells and abnormal esophageal motility, which simulates the functional and histopathological features of some AC patients. This suggests that eosinophil infiltration in esophageal muscularis propria may play a role in the pathogenesis of a subgroup of AC.

Effect of esophageal muscle fibrosis on prognosis of per-oral endoscopic myotomy (POEM) in achalasia patients

BACKGROUND AND AIMS

Although esophageal smooth muscle fibrosis of achalasia (AC) patients has been described, the role and mechanism remain unclear. The aim of this study was to evaluate the fibrosis in the distal esophageal muscle in patients with AC and explore its relationship with prognosis of per-oral endoscopic myotomy (POEM).

METHODS

Lower esophageal sphincter (LES) muscle from forty patients undergoing POEM for AC were obtained at the time of surgery. Control specimens consisted of similar muscle taken from distal esophagectomy for gastric tumors. The muscle fibrosis were assessed by Masson staining and confirmed by immunohistochemistry for collagen I and III. The total number of eosinophil within the myenteric propria were counted. In addition, clinical data were obtained through electronic medical records. Statistical comparison between groups were made.

RESULTS

A significantly higher proportion of fibrosis in AC as compared with controls (P = 0.000). Eosinophil count, TGF-β1, collagen I, and III were higher than those of control (P = 0.000, P = 0.001, P = 0.011, and P = 0.002, respectively). TGF-β1, collagen I, and III were positively correlated with eosinophil count (all P < 0.05). Furthermore, the proportion of severe LES fibrosis in patients who failed to respond to POEM two years after operation was higher than that in responders (P = 0.028). And, Eckardt score two years after POEM was also positively correlated with degree of fibrosis-related cytokines (all P < 0.05).

CONCLUSION

Smooth muscle fibrosis was prominent in lower part of esophagus of AC and positively correlated with severity of symptoms two years after POEM. The fibrosis might be relevant to eosinophil infiltration and TGF-β1. Further studies are required to more clearly delineate the mechanism of muscle fibrosis and its correlation with prognosis of therapy for this idiopathic disease.

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.

Lower esophageal sphincter muscle of patients with achalasia exhibits profound mast cell degranulation

BACKGROUND

Eosinophils and mast cells are key effectors of allergy. When they accumulate in the esophagus, their myoactive, pro-inflammatory, and cytotoxic products potentially could cause achalasia-like motility abnormalities and neuronal degeneration. We hypothesized that there is an allergy-mediated form of achalasia.

METHODS

LES muscle samples obtained during Heller myotomy from patients with achalasia or EGJ outflow obstruction (EGJOO) and from organ donor controls were immunostained for tryptase. Eosinophil and mast cell density, and mast cell degranulation were assessed. LES muscle was evaluated by qPCR for genes mediating smooth muscle Ca²⁺ handling and contraction.

KEY RESULTS

There were 13 patients (7 men, median age 59; 10 achalasia, 3 EGJOO) and 7 controls (4 men, median age 42). Eosinophils were infrequent in LES muscle, but mast cells were plentiful. Patients and controls did not differ significantly in LES mast cell density. However, 12 of 13 patients exhibited profound LES mast cell degranulation involving perimysium and myenteric plexus nerves, while only mild degranulation was seen in 2 of 7 controls. Hierarchical clustering analysis of qPCR data revealed two "mototype" LES gene expression patterns, with all type II patients in one mototype, and type I and III patients in the other.

CONCLUSIONS & INFERENCES

LES muscle of patients with achalasia or EGJOO exhibits striking mast cell degranulation, and patients with different achalasia manometric phenotypes exhibit different LES patterns of expression for genes mediating Ca²⁺ handling and muscle contraction. Although these findings are not definitive, they support our hypothesis that achalasia can be allergy-driven.

The etiology of achalasia: An immune-dominant disease

There is accumulating evidence suggesting that an autoimmune component is involved in esophageal achalasia. An increase in immune cells, cytokines, chemokines, and autoimmune antibodies in serum and infiltration of immune cells in tissues support the view that immune-mediated inflammation is a crucial pathogenesis of inhibitory neuron degeneration in the lower esophageal sphincter. Infection of viruses such as the herpes virus family has been suspected of provoking the autoimmune reaction. Meanwhile, previous reports on immunogenetics have proposed that specific risk alleles on the human leukocyte antigen complex define the susceptible population to achalasia. In this study we reviewed current knowledge regarding the immune-related factors of achalasia, including immunology, viral infection and immunogenetic variations.

Multiplex immunoassays reveal increased serum cytokines and chemokines associated with the subtypes of achalasia

BACKGROUND

Achalasia is an esophageal motility disorder with unknown etiology. Previous findings indicate that immune-mediated inflammatory process causes inhibitory neuronal degeneration. This study was designed to evaluate levels of serological cytokines and chemokines in patients with achalasia.

METHODS

We collected information from forty-seven patients with achalasia who underwent peroral endoscopic myotomy. Control samples were collected from forty-seven age- and sex-matched healthy people. The concentrations of serological cytokines and chemokines were analyzed by Luminex xMAP immunoassay. Serological and clinical data were compared between groups.

KEY RESULTS

Compared with healthy controls, achalasia patients had significantly increased concentrations of eleven cytokines and chemokines, namely, TGF-ß1 (P < .001), TGF-ß2 (P < .001), TGF-ß3 (P < .001), IL-1ra (P < .001), IL-17 (P = .005), IL-18 (P < .001), IFN-γ (P < .001), MIG (P < .001), PDGF-BB (P < .001), IP-10 (P = .003), and SCGF-B (P < .001). Gene ontology (GO) and network functional enrichment analysis revealed regulation of signaling receptor activity and receptor-ligand activity were the most related pathways of these cytokines and chemokines. Levels of twelve cytokines and chemokines were significantly increased in type III compared with I/II achalasia, namely, TGF-ß2, IL-1ra, IL-2Ra, IL-18, MIG, IFN-γ, SDF-1a, Eotaxin, PDGF-BB, IP-10, MCP-1, and TRAIL.

CONCLUSIONS AND INFERENCES

Patients with achalasia exhibited increased levels of serological cytokines and chemokines. Levels of cytokines and chemokines were significantly increased in type III than in type I/II achalasia. Cytokines and chemokines might contribute to the inflammatory development of achalasia.

Mast cell infiltration associated with loss of interstitial cells of Cajal and neuronal degeneration in achalasia

BACKGROUND

Achalasia is a motility disorder of unknown etiology. Previous studies supported the hypothesis that autoimmune-mediated inflammatory responses produce inhibitory neuronal degeneration. This study was designed to explore the role of mast cells in achalasia.

METHODS

We collected information from 116 patients with achalasia who underwent peroral endoscopic myotomy between December 2016 and May 2017. Lower esophageal sphincter (LES) muscle biopsy was performed in all patients with achalasia, as well as 20 control subjects. The number of mast cells, interstitial cells of Cajal (ICCs), nNOS-positive cells, and S-100-positive cells in the LES were evaluated by immunohistochemistry. Pathological and clinical data were compared between groups.

KEY RESULTS

Compared with controls, the LES of patients with achalasia had significantly fewer ICCs, nNOS-positive cells, and S-100-positive cells and a higher number of mast cells (all P < 0.001). Furthermore, the increased mast cell infiltration was significantly associated with decreased ICCs, nNOS-positive cells, and S-100-positive cells in patients with achalasia (all P < 0.05). Clinically, the number of strongly positive mast cells was highest in patients with type I achalasia and lowest in those with type III achalasia (P < 0.001). In addition, patients with a history of autoimmune disease or viral infection had greater mast cell infiltration in the LES muscle (P = 0.040).

CONCLUSIONS & INFERENCES

In patients with achalasia, mast cell infiltration in the LES muscle is increased, in association with loss of ICCs and neuronal degeneration. Mast cells may thereby play a crucial role in the development of achalasia.

Mucosally Expressed Cytokines are Associated with the Esophageal Motility Function

BACKGROUND AND AIM

Although basic research has shown that certain cytokines affect gastrointestinal motility, the clinical evidence is lacking. The objective of this study was to explore the association between mucosally expressed cytokines and the esophageal motility function in humans.

METHODS

We enrolled a total of 57 patients with suspected esophageal motility disorders (EMDs) who underwent high-resolution manometry.

RESULTS

The diagnoses of the patients were as follows: normal esophageal motility (n = 25), ineffective esophageal motility (n = 5), esophagogastric junction outflow obstruction (EGJOO; n = 10), distal esophageal spasm (n = 5), achalasia (n = 10), absent contractility (n = 1), and jackhammer esophagus (n = 1). The expression of tumor necrosis factor (TNF)-α in the esophagogastric junction (EGJ) was significantly higher in EGJOO (14.6, 14.0-15.8, n = 10) than in normal esophageal motility (13.3, 12.8-14.1, n = 25); however, there was no difference in the expression of TNF-α between achalasia (13.4, 13.0-14.1, n = 10) and normal esophageal motility (13.3, 12.8-14.1, n = 25). EGJOO was discriminated from achalasia/normal by a linear discriminant analysis (AUC = 0.917). A multivariable regression analysis revealed that interleukin (IL)-13 and IL-23A were predictive of the distal contractile integral, whereas TNF-α and IL-6 were predictive of the basal EGJ pressure.

CONCLUSIONS

The esophageal motility was associated with mucosally expressed cytokines in humans; these cytokines could be useful targets for the diagnosis and treatment of EMDs.

The spectrum of achalasia: lessons from studies of pathophysiology and high-resolution manometry

High-resolution manometry and recently described analysis algorithms, summarized in the Chicago Classification, have increased the recognition of achalasia. It has become apparent that the cardinal feature of achalasia, impaired lower esophageal sphincter relaxation, can occur in several disease phenotypes: without peristalsis, with premature (spastic) distal esophageal contractions, with panesophageal pressurization, or with peristalsis. Any of these phenotypes could indicate achalasia; however, without a disease-specific biomarker, no manometric pattern is absolutely specific. Laboratory studies indicate that achalasia is an autoimmune disease in which esophageal myenteric neurons are attacked in a cell-mediated and antibody-mediated immune response against an uncertain antigen. This autoimmune response could be related to infection of genetically predisposed subjects with herpes simplex virus 1, although there is substantial heterogeneity among patients. At one end of the spectrum is complete aganglionosis in patients with end-stage or fulminant disease. At the opposite extreme is type III (spastic) achalasia, which has no demonstrated neuronal loss but only impaired inhibitory postganglionic neuron function; it is often associated with accentuated contractility and could be mediated by cytokine-induced alterations in gene expression. Distinct from these extremes is progressive plexopathy, which likely arises from achalasia with preserved peristalsis and then develops into type II achalasia and then type I achalasia. Variations in its extent and rate of progression are likely related to the intensity of the cytotoxic T-cell assault on the myenteric plexus. Moving forward, we need to integrate the knowledge we have gained into treatment paradigms that are specific for individual phenotypes of achalasia and away from the one-size-fits-all approach.

Synopsis of investigations into proposed theories on the etiology of achalasia

The current state of research into the etiology of achalasia only allows for speculation. To date, several studies have been performed investigating genetic, immune, and infectious disease mechanisms; however, none of these have been conclusive. Further research into this topic is warranted given the severity of the disease, and it may be possible that all of these mechanisms are involved in the pathophysiology of the disease.

Cytokine-induced alterations of gastrointestinal motility in gastrointestinal disorders

Inflammation and immune activation in the gut are usually accompanied by alteration of gastrointestinal (GI) motility. In infection, changes in motor function have been linked to host defense by enhancing the expulsion of the infectious agents. In this review, we describe the evidence for inflammation and immune activation in GI infection, inflammatory bowel disease, ileus, achalasia, eosinophilic esophagitis, microscopic colitis, celiac disease, pseudo-obstruction and functional GI disorders. We also describe the possible mechanisms by which inflammation and immune activation in the gut affect GI motility. GI motility disorder is a broad spectrum disturbance of GI physiology. Although several systems including central nerves, enteric nerves, interstitial cells of Cajal and smooth muscles contribute to a coordinated regulation of GI motility, smooth muscle probably plays the most important role. Thus, we focus on the relationship between activation of cytokines induced by adaptive immune response and alteration of GI smooth muscle contractility. Accumulated evidence has shown that Th1 and Th2 cytokines cause hypocontractility and hypercontractility of inflamed intestinal smooth muscle. Th1 cytokines downregulate CPI-17 and L-type Ca²⁺ channels and upregulate regulators of G protein signaling 4, which contributes to hypocontractility of inflamed intestinal smooth muscle. Conversely, Th2 cytokines cause hypercontractilty via signal transducer and activator of transcription 6 or mitogen-activated protein kinase signaling pathways. Th1 and Th2 cytokines have opposing effects on intestinal smooth muscle contraction via 5-hydroxytryptamine signaling. Understanding the immunological basis of altered GI motor function could lead to new therapeutic strategies for GI functional and inflammatory disorders.

Association of IL10 promoter polymorphisms with idiopathic achalasia

Idiopathic achalasia is an esophageal motor disorder of unknown etiology. A wealth of evidence supports the concept that achalasia is an immune-mediated disease. According to this evidence, achalasia has been significantly associated with specific alleles of the human leukocyte antigen class II, PTPN22 and IL23R. Several studies have demonstrated association of the IL10 gene with different inflammatory disorders. Our aim was to evaluate the role of functional IL10 promoter polymorphisms in susceptibility to idiopathic achalasia. A case-control study was performed with the -1082, -819, and -592 IL10 promoter polymorphisms in 282 patients and 529 controls and in an independent replication set of 75 patients and 575 controls. The GCC haplotype of the IL10 promoter was reported to be associated with a lower risk of achalasia in the discovery sample (odds ratio [OR] = 0.79, 95% confidence interval [CI] = 0.64-0.98, p = 0.029). This association was validated in a replication set (OR = 0.69, 95% CI = 0.48-1.00, p = 0.04). In the combined analysis no heterogeneity was observed between the 2 sample sets and the GCC haplotype was significantly associated with the disease (OR(MH) = 0.76, 95% CI = 0.63-0.91, p = 0.003). Our results provide the first evidence for an association between IL10 promoter polymorphisms and idiopathic achalasia, suggesting that the interleukin-10 cytokine may contribute to the pathogenesis of this disease.

Association between idiopathic achalasia and IL23R gene

BACKGROUND

Idiopathic achalasia is a primary esophageal motor disorder of unknown etiology. Different evidences have been reported in support of achalasia as the result of an autoimmune and inflammatory process leading to neuronal cell loss. According to this, idiopathic achalasia has been significantly associated with specific alleles of the human leukocyte antigen system class II, although few reports studying association with other loci can be found in the literature. Recent studies have shown association of a non-synonymous polymorphism within the IL23R gene with different chronic inflammatory disorders, including Barrett's esophagus. The purpose of this study was to assess whether the IL23R coding variant Arg381Gln polymorphism is involved in susceptibility to idiopathic achalasia.

METHODS

We performed a case-control study including 262 patients with idiopathic achalasia and 802 healthy subjects, all of them white Spaniards. Achalasia patients were diagnosed on the basis of clinical, radiographic, endoscopic, and manometric criteria. All samples were genotyped for the IL23R Arg381Gln polymorphism using TaqMan technology.

KEY RESULTS

The minor allele of the Arg381Gln polymorphism was significantly increased in patients compared with healthy controls (OR = 1.46, 95% CI = 1.01-2.11, P = 0.036). This association seems to be specific to male patients with disease onset after 40 years (OR = 2.33, 95% CI = 1.29-4.16, P = 0.002).

CONCLUSIONS & INFERENCES

Our results suggest a role of IL23R in idiopathic achalasia predisposition and extend the evidence of the general influence of this gene in autoimmune and inflammatory diseases.