Esophageal achalasia: is the herpes simplex virus really innocent?

Association of circulating cytokine levels and tissue-infiltrating myeloid cells with achalasia: results from Mendelian randomization and validation through clinical characteristics and single-cell RNA sequencing

BACKGROUND

Achalasia is a rare motility disorder of the esophagus often accompanied by immune dysregulation, yet specific underlying mechanisms remain poorly understood.

METHODS

We utilized Mendelian randomization (MR) to explore the causal effects of cytokine levels on achalasia, with cis-expression/protein quantitative trait loci (cis-eQTLs/pQTLs) for 47 cytokines selected from a genome-wide association study (GWAS) meta-analysis and GWAS data for achalasia obtained from FinnGen. For cytokines significantly linked to achalasia, we analyzed their plasma concentrations and expression differences in the lower esophageal sphincter (LES) using enzyme-linked immunosorbent assay and single-cell RNA sequencing (scRNA-seq) profiling, respectively. We further employed bioinformatics approaches to investigate underlying mechanisms.

RESULTS

We revealed positive associations of circulating Eotaxin, macrophage inflammatory protein-1b (MIP1b), soluble E-selectin (SeSelectin) and TNF-related apoptosis-inducing ligand (TRAIL) with achalasia. When combining MR findings with scRNA-seq data, we observed upregulation of TRAIL (OR = 2.70, 95% CI, 1.20-6.07), encoded by TNFSF10, in monocytes and downregulation of interleukin-1 receptor antagonist (IL-1ra) (OR = 0.70, 95% CI 0.59-0.84), encoded by IL1RN, in FOS_macrophages in achalasia. TNFSF10high monocytes in achalasia displayed activated type I interferon signaling, and IL1RNlow FOS_macrophages exhibited increased intercellular communications with various lymphocytes, together shaping the proinflammatory microenvironment of achalasia.

CONCLUSIONS

We identified circulating Eotaxin, MIP1b, SeSelectin and TRAIL as potential drug targets for achalasia. TNFSF10high monocytes and IL1RNlow macrophages may play a role in the pathogenesis of achalasia.

Focus on Achalasia in the Omics Era

Achalasia is a rare and complex esophageal disease of unknown etiology characterized by difficulty in swallowing due to the lack of opening of the lower esophageal sphincter and the absence of esophageal peristalsis. Recent advancements in technology for analyzing DNA, RNA and biomolecules in high-throughput techniques are offering new opportunities to better understand the etiology and the pathogenetic mechanisms underlying achalasia. Through this narrative review of the scientific literature, we aim to provide a comprehensive assessment of the state-of-the-art knowledge on omics of achalasia, with particular attention to those considered relevant to the pathogenesis of the disease. The notion and importance of the multi-omics approach, its limitations and future directions are also introduced, and it is highlighted how the integration of single omics data will lead to new insights into the development of achalasia and offer clinical tools which will allow early diagnosis and better patient management.

Research gap in esophageal achalasia: a narrative review

In recent years, new translational evidence, diagnostic techniques, and innovative therapies have shed new light on esophageal achalasia and revamped the attention on this relatively rare motility disorder. This narrative review aims to highlight the most recent progress and the areas where further research is needed. The four senior authors identified five topics commonly discussed in achalasia management: i.e. pathogenesis, role of functional lumen imaging probe in the diagnostic flow chart of achalasia, how to define the outcome of achalasia treatments, how to manage persistent chest pain after the treatment, and if achalasia patients' may benefit from a regular follow-up. We searched the bibliographic databases to identify systematic reviews, meta-analyses, randomized control trials, and original research articles in English up to December 2023. We provide a summary with the most recent findings in each of the five topics and the critical points where to address future research, such as the immune-genetic patterns of achalasia that might explain the transition among the different phenotypes, the need for a validated clinical definition of treatment success, the use of neuromodulators to manage chest pain, and the need for identifying achalasia patients at risk for cancer and who may benefit of long-term follow-up. Although undoubtedly, progress has been made on the definition and management of achalasia, unmet needs remain. Debated aspects range from mechanistic insights, symptoms, objective measure relationships, and accurate clinical responses to therapeutic interventions. Translational research is eagerly awaited to answer these unresolved questions.

A single-cell transcriptional landscape of immune cells shows disease-specific changes of T cell and macrophage populations in human achalasia

Achalasia is a rare motility disorder of the esophagus caused by the gradual degeneration of myenteric neurons. Immune-mediated ganglionitis has been proposed to underlie the loss of myenteric neurons. Here, we measure the immune cell transcriptional profile of paired lower esophageal sphincter (LES) tissue and blood samples in achalasia and controls using single-cell RNA sequencing (scRNA-seq). In achalasia, we identify a pattern of expanded immune cells and a specific transcriptional phenotype, especially in LES tissue. We show C1QC+ macrophages and tissue-resident memory T cells (TRM), especially ZNF683+ CD8+ TRM and XCL1+ CD4+ TRM, are significantly expanded and localized surrounding the myenteric plexus in the LES tissue of achalasia. C1QC+ macrophages are transcriptionally similar to microglia of the central nervous system and have a neurodegenerative dysfunctional phenotype in achalasia. TRM also expresses transcripts of dysregulated immune responses in achalasia. Moreover, inflammation increases with disease progression since immune cells are more activated in type I compared with type II achalasia. Thus, we profile the immune cell transcriptional landscape and identify C1QC+ macrophages and TRM as disease-associated immune cell subsets in achalasia.

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.

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.

Esophageal Achalasia: Pathophysiology, Clinical Presentation, and Diagnostic Evaluation

Esophageal achalasia is a primary esophageal motility disorder characterized by the absence of esophageal peristalsis and failure of the lower esophageal sphincter to relax in response to swallowing. These abnormalities lead to impaired emptying of food from the esophagus into the stomach with resulting food stasis. Most patients experience severe dysphagia, and regurgitation can lead to aspiration and respiratory problems. Consequently, the quality of life of patients affected by achalasia is severely impacted. A thorough evaluation with upper endoscopy, barium swallow, and esophageal manometry is mandatory to establish the diagnosis and plan the optimal treatment. In selected patients, an ambulatory pH monitoring is recommended to distinguish between gastroesophageal reflux disease and achalasia.

Etiology and Pathogenesis of Idiopathic Achalasia

This review examines the etiology and pathogenesis of idiopathic achalasia. This disease is clinically characterized by dysphagia of solids and liquids due to the presence of simultaneous or absent esophageal contractions and impaired or absent relaxation of the lower esophageal sphincter. It includes a review of (a) etiology and pathogenesis of this inflammatory process that damage the ganglion cells of the Auerbach plexus that is limited to the esophagus; (b) genetic abnormalities and polymorphisms associated with this disease that may help explain its heterogeneity expressed by the different motility abnormalities of its phenotypes as well as differences in its clinical progression. These different genetic abnormalities may be responsible for the slow progression of types I or II phenotypes; (c) indirect evidence of viruses present in these patients that may initiate its development; (d) the abnormalities of the muscle layer that may be responsible for the dilation of the body of the esophagus that ultimately causes the sigmoid-like esophagus in the very last phase of this disease. This progression to the end-stage phase tends to occur in about 5% of patients. And, (e) the chronic inflammatory abnormalities in the squamous mucosa that may be the cause of the dysplastic and neoplastic changes that may lead to squamous cell carcinoma whose incidence in this disease is increased. These mucosal abnormalities are usually present in patients with markedly dilated body of the esophagus and severe food stasis.

Comprehensive epidemiological and genotype-phenotype analyses in a large European sample with idiopathic achalasia

BACKGROUND AND AIM

Although an eight-residue insertion in HLA-DQβ1 has been recently identified as a genetic risk factor for idiopathic achalasia, other risk factors are still unknown. In the present study, we carried out an epidemiological survey and a genotype-phenotype (G×P) analysis to gain further insights into the etiology of achalasia.

METHODS

We obtained medical data from 696 achalasia patients and 410 controls, as well as their first-degree relatives (2543 of patients and 1497 of controls). For the G×P analysis, we stratified the patients into HLA-DQβ1 insertion carriers and noncarriers.

RESULTS

Our data show that patients are more often affected by viral infections before achalasia onset (P<0.0001, most significantly for varicella zoster virus infections). In addition, allergic (P=0.0005) and autoimmune disorders (P=0.0007, most significantly for psoriasis and Sjögren's syndrome) represent comorbid disease conditions. First-degree relatives of patients also show higher prevalence rates of allergic disorders (P=0.0007) and psoriasis (P=0.016) compared with control relatives. Moreover, the G×P analysis reveals that achalasia is triggered by pregnancies in female HLA-DQβ1 insertion carriers (P=0.031).

CONCLUSION

Our data point to a role of viral infections in the development of achalasia. In addition, they provide evidence for a relationship between achalasia and allergic, as well as autoimmune, disorders. Furthermore, pregnancy seems to be a disease-triggering factor in female HLA-DQβ1 insertion carriers, which points to hormonal and/or immunosuppressive factors influencing disease development.

Clinical aspects of neurointestinal disease: Pathophysiology, diagnosis, and treatment

The enteric nervous system (ENS) is involved in the regulation of virtually all gut functions. Conditions referred to as enteric neuropathies are the result of various mechanisms including abnormal development, degeneration or loss of enteric neurons that affect the structure and functional integrity of the ENS. In the past decade, clinical and molecular research has led to important conceptual advances in our knowledge of the pathogenetic mechanisms of these disorders. In this review we consider ENS disorders from a clinical perspective and highlight the advancing knowledge regarding their pathophysiology. We also review current therapies for these diseases and present potential novel reparative approaches for their treatment.

Histopathologic patterns among achalasia subtypes

BACKGROUND

Achalasia has three distinct manometric phenotypes. This study aimed to determine if there were corresponding histopathologic patterns.

METHODS

We retrospectively examined surgical muscularis propria biopsies obtained from 46 patients during laparoscopic esophagomyotomy. Pre-operative (conventional) manometry tracings were reviewed by two expert gastroenterologists who categorized patients into Chicago Classification subtypes. Pathology specimens were graded on degree of neuronal loss, inflammation, fibrosis, and muscle changes.

KEY RESULTS

Manometry studies were categorized as follows: type I (n = 20), type II (n = 20), type III (n = 3), and esophagogastric junction outflow obstruction (EGJOO) (n = 3). On histopathology, complete ganglion cell loss occurred in 74% of specimens, inflammation in 17%, fibrosis in 11%, and muscle atrophy in 2%. Comparing type I and type II specimens, there was a statistically significant greater proportion of type I specimens with aganglionosis (19/20 vs 13/20, p = 0.044) and a statistically significant greater degree of ganglion cell loss in type I specimens (Wilcoxon Rank-Sum, p = 0.016). CD3(+) /CD8(+) cytotoxic T cells represented the predominant inflammatory infiltrate on immunohistochemistry. Three patients had completely normal appearing tissue (1 each in type II, type III, EGJOO).

CONCLUSIONS & INFERENCES

The greater degree, but similar pattern, of ganglion cell loss observed in type I compared to type II achalasia specimens suggests that type I achalasia represents a progression from type II achalasia. The spectrum of histopathologic findings - from complete neuronal loss to lymphocytic inflammation to apparently normal histopathology - emphasizes that 'achalasia' represents a pathogenically heterogeneous patient group with the commonality being EGJ outflow obstruction.

Idiopathic (primary) achalasia: a review

Idiopathic achalasia is a primary esophageal motor disorder characterized by loss of esophageal peristalsis and insufficient lower esophageal sphincter relaxation in response to deglutition. Patients with achalasia commonly complain of dysphagia to solids and liquids, bland regurgitation often unresponsive to an adequate trial of proton pump inhibitor, and chest pain. Weight loss is present in many, but not all patients. Although the precise etiology is unknown, it is often thought to be either autoimmune, viral immune, or neurodegenerative. The diagnosis is based on history of the disease, barium esophagogram, and esophageal motility testing. Endoscopic assessment of the gastroesophageal junction and gastric cardia is necessary to rule out malignancy. Newer diagnostic modalities such as high resolution manometry help in predicting treatment response in achalasia based on esophageal pressure topography patterns identifying three phenotypes of achalasia (I-III) and outcome studies suggest better treatment response with types I and II compared to type III. Although achalasia cannot be permanently cured, excellent outcomes are achieved in over 90 % of patients. Current medical and surgical therapeutic options (pneumatic dilation, endoscopic and surgical myotomy, and pharmacologic agents) aim at reducing the LES pressure and facilitating esophageal emptying by gravity and hydrostatic pressure of retained food and liquids. Either graded pneumatic dilatation or laparoscopic surgical myotomy with a partial fundoplication are recommended as initial therapy guided by patient age, gender, preference, and local institutional expertise. The prognosis in achalasia patients is excellent. Most patients who are appropriately treated have a normal life expectancy but the disease does recur and the patient may need intermittent treatment.

Achalasia in Korea: an epidemiologic study using a national healthcare database

Owing to the rarity of the disease, epidemiologic information on achalasia is limited. This study aimed to investigate the epidemiology and treatment patterns of achalasia in the population of Korea using a national healthcare database. The diagnostic code K22.0 of the International Classification of Diseases was used to identify cases of achalasia between 2007 and 2011. Treatment modalities for achalasia were identified using the electronic data interchange codes Q7642 or Q7641 for balloon dilation and QA421 or QA422 for esophago-cardiomyotomy. A total of 3,105 patients with achalasia (1,447 men; mean age, 52.5 yr) were identified between 2007 and 2011, indicating a prevalence of 6.29/100,000 (95% confidence interval [CI], 4.94-7.66) during this 5-yr period. A total of 191 incident cases of achalasia (82 men; mean age, 49.5 yr), which were not diagnosed as achalasia in the previous 4 yr, were detected in 2011, indicating an incidence of 0.39/100,000 (95% CI, 0.15-0.63) for that year. During the study period, balloon dilation therapy was performed a total of 975 times in 719 patients, and surgical esophago-cardiomyotomy was performed once per patient in 17 patients. This is the first population-based epidemiologic study of achalasia in Korea.

Achalasia

Achalasia is a rare motility disorder of the oesophagus characterised by loss of enteric neurons leading to absence of peristalsis and impaired relaxation of the lower oesophageal sphincter. Although its cause remains largely unknown, ganglionitis resulting from an aberrant immune response triggered by a viral infection has been proposed to underlie the loss of oesophageal neurons, particularly in genetically susceptible individuals. The subsequent stasis of ingested food not only leads to symptoms of dysphagia, regurgitation, chest pain, and weight loss, but also results in an increased risk of oesophageal carcinoma. At present, pneumatic dilatation and Heller myotomy combined with an anti-reflux procedure are the treatments of choice and have comparable success rates. Per-oral endoscopic myotomy has recently been introduced as a new minimally invasive treatment for achalasia, but there have not yet been any randomised clinical trials comparing this option with pneumatic dilatation and Heller myotomy.

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.

2011 update on esophageal achalasia

There have been some breakthroughs in the diagnosis and treatment of esophageal achalasia in the past few years. First, the introduction of high-resolution manometry with pressure topography plotting as a new diagnostic tool has made it possible to classify achalasia into three subtypes. The most favorable outcome is predicted for patients receiving treatment for type II achalasia (achalasia with compression). Patients with type I(classic achalasia) and type III achalasia (spastic achalasia) experience a less favorable outcome. Second, the first multicenter randomized controlled trial published by the European Achalasia Trial group reported 2-year follow-up results indicating that laparoscopic Heller myotomy was not superior to endoscopic pneumatic dilation (PD). Although the follow-up period was not long enough to reach a convincing conclusion, it merits the continued use of PD as a generally available technique in gastroenterology. Third, the novel endoscopic technique peroral endoscopic myotomy is a promising option for treating achalasia, but it requires increased experience and cautious evaluation. Despite all this good news, the bottom line is a real breakthrough from the basic studies to identify the actual cause of achalasia that may impede treatment success is still anticipated.

The involvement of nitric oxide synthase neurons in enteric neuropathies

Nitric oxide (NO), produced by the neural nitric oxide synthase enzyme (nNOS) is a transmitter of inhibitory neurons supplying the muscle of the gastrointestinal tract. Transmission from these neurons is necessary for sphincter relaxation that allows the passage of gut contents, and also for relaxation of muscle during propulsive activity in the colon. There are deficiencies of transmission from NOS neurons to the lower esophageal sphincter in esophageal achalasia, to the pyloric sphincter in hypertrophic pyloric stenosis and to the internal anal sphincter in colonic achalasia. Deficits in NOS neurons are observed in two disorders in which colonic propulsion fails, Hirschsprung's disease and Chagas' disease. In addition, damage to NOS neurons occurs when there is stress to cells, in diabetes, resulting in gastroparesis, and following ischemia and reperfusion. A number of factors may contribute to the propensity of NOS neurons to be involved in enteric neuropathies. One of these is the failure of the neurons to maintain Ca(2+) homeostasis. In neurons in general, stress can increase cytoplasmic Ca(2+), causing a Ca(2+) toxicity. NOS neurons face the additional problem that NOS is activated by Ca(2+). This is hypothesized to produce an excess of NO, whose free radical properties can cause cell damage, which is exacerbated by peroxynitrite formed when NO reacts with oxygen free radicals.

Morphofunctional analysis of experimental model of esophageal achalasia in rats

We carried out a detailed analysis of rat model of esophageal achalasia previously developed by us. Manifest morphological and functional disorders were observed in experimental achalasia: hyperplasia of the squamous epithelium, reduced number of nerve fibers, excessive growth of fibrous connective tissue in the esophageal wall, high contractile activity of the lower esophageal sphincter, and reduced motility of the longitudinal muscle layer. Changes in rat esophagus observed in experimental achalasia largely correlate with those in esophageal achalasia in humans. Hence, our experimental model can be used for the development of new methods of disease treatment.

Enhanced reactivity of peripheral blood immune cells to HSV-1 in primary achalasia

OBJECTIVE

Achalasia is the best characterized oesophageal motor disorder but the etiology is unknown. The pathology is characterized by a decrease in nitric oxide-producing neurons and the presence of an activated T-cell inflammatory infiltrate in the myenteric plexus that are reactive to HSV-1 viral antigens. These findings are not present in normal controls. The current study compared the reactivity of peripheral blood mononuclear cells (PBMCs) between patients with primary achalasia and normal controls to determine if PBMCs of patients exhibit a similar heightened reactivity to the virus.

MATERIAL AND METHODS

Whole blood culture experiments were conducted with heparinized peripheral venous blood obtained from 151 patients with primary achalasia and 118 healthy controls. Whole blood was cultured in the presence of ultraviolet inactivated HSV-1 or conditioned cell culture media. Reactivity of mononuclear cells to viral antigens was quantified by measuring expression of the cytokine gene interferon-gamma using Taqman real-time polymerase chain reaction. Data are expressed as cytokine fold change corresponding to ratio of interferon-gamma messenger RNA copies produced in antigen stimulated versus unstimulated cells.

RESULTS

The interferon-gamma fold change was higher in cases 61.33 (20.54-217.00) than controls 49.67 (10.05-157.05). Mean fold change difference between cases and controls was 1.66 times (95% confidence interval 1.17-2.34, p = 0.004).

CONCLUSIONS

These results indicate that the PBMCs of patients with primary achalasia show an enhanced immune response to HSV-1 antigens. The data suggest that there is persistent stimulation of immune cells by herpes simplex virus type 1 (HSV-1) or HSV-1 like antigen moieties.

An immunohistochemical study of the myenteric plexus in idiopathic achalasia

BACKGROUND

Achalasia is a primary esophageal motor disorder characterized by degenerative changes of the myenteric plexus. The pathophysiologic abnormalities may be the final result of several intermeshing mechanisms, and more than one single factor may cause the motor abnormalities.

AIMS

To report our experience in investigating the myenteric plexus of achalasia patients undergoing esophagomyotomy.

PATIENTS AND METHODS

Tissue samples from 12 patients undergoing Heller myotomy for achalasia were evaluated and compared with esophageal tissue specimens from 7 controls. Enteric neurons and interstitial cells of Cajal (ICC) were assessed by immunohistochemical methods, and the presence of vasoactive intestinal polypeptide ergic fibers and of CD3 lymphocytes. The possible presence of herpesvirus was also assessed by immunohistochemistry, whereas that of papillomavirus was assessed by in-situ hybridization.

RESULTS

Compared with controls, achalasia patients displayed a significant decrease of both enteric neurons and ICC. Immunoreactivity for vasoactive intestinal polypeptide was completely absent in each patient. CD3 staining disclosed myenteric plexitis in 5 (42%) patients; no control patient had plexitis. All patients were completely negative for the presence of both herpes simplex virus and human papillomavirus.

CONCLUSIONS

The enteric nervous system of the lower esophageal sphincter area is impaired in patients with "idiopathic achalasia," and the abnormalities involve ICC and neurons in many patients. The triggering factors for these abnormalities are, however, still unknown.

A controversy that has been tough to swallow: is the treatment of achalasia now digested?

Esophageal achalasia is a rare neurodegenerative disease of the esophagus and the lower esophageal sphincter that presents within a spectrum of disease severity related to progressive pathological changes, most commonly resulting in dysphagia. The pathophysiology of achalasia is still incompletely understood, but recent evidence suggests that degeneration of the postganglionic inhibitory nerves of the myenteric plexus could be due to an infectious or autoimmune mechanism, and nitric oxide is the neurotransmitter affected. Current treatment of achalasia is directed at palliation of symptoms. Therapies include pharmacological therapy, endoscopic injection of botulinum toxin, endoscopic dilation, and surgery. Until the late 1980s, endoscopic dilation was the first line of therapy. The advent of safe and effective minimally invasive surgical techniques in the early 1990s paved the way for the introduction of laparoscopic myotomy. This review will discuss the most up-to-date information regarding the pathophysiology, diagnosis, and treatment of achalasia, including a historical perspective. The laparoscopic Heller myotomy with partial fundoplication performed at an experienced center is currently the first line of therapy because it offers a low complication rate, the most durable symptom relief, and the lowest incidence of postoperative gastroesophageal reflux.

Long-term outcomes of laparoscopic Heller myotomy for achalasia

BACKGROUND

Short-term outcomes of laparoscopic Heller myotomy (LHM) for achalasia have been excellent, although the long-term durability of this operation remains to be established. The aim of this study was to evaluate the long-term outcomes of LHM.

METHODS

A single-institution review of patients undergoing LHM between 1992 and 2003 with > or =5 years follow-up. Failure was defined as symptom recurrence requiring reoperation. Univariate and multiple regression analysis were performed to identify preoperative variables predictive of long-term success.

RESULTS

A total of 46 patients underwent LHM with Toupet (n = 42) or Dor (n = 4) fundoplication. At a mean follow-up of 6.4 years, 37 (80%) patients remained free from failure. Mean time to symptom recurrence in those failing LHM was 21.3 months (range, 0.5-77). Causes of failure included nonfunctioning end-stage esophagus (n = 4), fibrotic narrowing at the gastroesophageal junction (n = 4), and tight wrap (n = 1). Univariate analysis identified high preoperative lower esophageal sphincter pressure (LESP), no prior therapy, short duration of symptoms, and absence of sigmoidal esophagus as predictors of long-term success (P < or = .044 each). High LESP remained the only predictor of long-term durability in multiple regression analysis (P = .043). Reoperations included redo myotomy (n = 2), esophagectomy (n = 6), or both (n = 1). At final follow-up, 44 (96%) patients reported significant symptom improvement compared with pre-LHM severity.

CONCLUSION

LHM is associated with an 80% long-term success rate. Successful LHM may be predicted by high LESP, no prior therapy, short symptom duration, or absence of sigmoidal esophagus. In this series, failures of LHM underwent reoperation (redo myotomy or esophagectomy) with good results.

Achalasia--which method of treatment to choose for senior patients?

BACKGROUND

Achalasia is an uncommon illness affecting 1 per 100,000 patients a year. It encompasses a rare, primary motor disorder of the distal esophagus.

METHODS

Over the period 1998-2006, 115 patients underwent various treatments for achalasia; the subgroup of seniors consisted of 26 patients. Six patients of these (age 69.7 y) underwent a modified Heller cardiomyotomy due to failure of previous endoscopic interventions. Standard esophageal manometry and 24 hour pH metry were performed pre- and postoperatively.

RESULTS

Six senior patients with achalasia underwent a laparoscopic Heller myotomy. Average preoperative tonus of the LES was 55 mmHg, postoperative tonus of the LES decreased to 11 mmHg. We performed Toupet partial fundoplication in all patients; no microperforation of the esophagus was found in the preoperative esophagoscopy. We recorded minimal pathological gastroesophageal reflux in pH metry - the average preoperative DeMeester score was 8, postoperatively 10.5. Prolonged dysphagia was not present in any patient--preoperative GIQLI score was 94, postoperative score was 106. There was no mortality or morbidity in the group of the operated patients.

CONCLUSION

Our operational results and postoperative follow-up show that laparoscopic Heller myotomy with Toupet partial fundoplication is a safe and effective treatment and can be recommended as the method of first choice for senior patients with no contraindication for laparoscopic operation.

Impact of genetic polymorphisms on the pathogenesis of achalasia: an age-dependent paradigm?

A wealth of evidence supports the concept that achalasia represents an autoimmune disorder in which a triggering factor (probably a virus) is the starter of an uncontrolled myenteric ganglionitis leading to neurodegeneration. The reasons whereby this process occurs only in some individuals and at the oesophageal level are unknown, but it is reasonable to assume that some genetic influence may affect the achalasia phenotype, making some individuals more or less susceptible to the disease. Association studies between achalasia and polymorphisms of genes involved in the regulation of immune responses may help to explain the complexity of achalasia pathogenesis and progression.

Herpes simplex virus and the alimentary tract

Herpes simplex virus (HSV) infection is well known as a sexually transmitted disease. However, relatively little has been published concerning the presentations and treatment of HSV infection within the gastrointestinal tract, where HSV most commonly affects the esophagus in both immunocompromised and immunocompetent patients. HSV proctitis is not uncommon and occurs primarily in males having sex with males. In patients with normal immune systems, gastrointestinal HSV infections are generally self-limited and rarely require antiviral therapy. Treatment of infection is suggested for immunocompromised patients, though no large randomized controlled trials have been performed. This article reviews the manifestations of HSV infection within the luminal gastrointestinal tract and options for diagnosis and treatment.

Achalasia: virus-induced euthanasia of neurons?

Achalasia, a motor disorder of the esophagus, is characterized by myenteric plexitis leading to neuronal loss. Cytotoxic T cells, isolated from the lower esophageal sphincter of achalasia patients, respond to human herpes virus-1 (HSV-1) with gamma-IFN (and to a lesser extent IL-2) production and clonal proliferation. In addition, HSV-1 DNA was demonstrated in the vast majority of patients, but also in controls. These exciting data suggest that achalasia is an immune-mediated inflammatory disease in which a (latent) infection with HSV-1 leads to persistent immune activation and self-destruction of esophageal neurons, most likely in genetic susceptible subjects only.

T cells in the myenteric plexus of achalasia patients show a skewed TCR repertoire and react to HSV-1 antigens

OBJECTIVE

The loss of myenteric neurons in the lower esophageal sphincter (LES) characterizes achalasia, an esophageal motor disorder. Because the presence of lymphocytic infiltrates suggests an immuno-mediated mechanism ongoing at the sites of disease, we investigated the T-cell receptor (TCR) repertoire and the ability to recognize human herpes virus type 1 (HSV-1) antigens of LES-infiltrating T lymphocytes in achalasia patients.

METHODS

Fifty-nine patients with idiopathic achalasia and 38 heart-beating cadaveric multiorgan donors (controls) were studied. By flow cytometry evaluation and CDR3 length spectratyping analysis, the lymphocytes of 18 patients and 15 controls were analyzed, whereas 41 patients and 23 controls were employed for functional assays.

RESULTS

Achalasia patients were characterized by a significantly higher esophagus lymphocytic infiltrate than controls (24.71%+/- 3.11 and 9.54%+/- 1.34, respectively; P < 0.05), mainly represented by CD3+CD8+ T cells. The characterization of TCR beta chain repertoire of CD3+ cells showed the expression of a limited number of TCR beta variable (BV) gene families (from two to five out of 26), with highly restricted spectratypes, suggesting a disease-associated oligoclonal selection of T cells. Furthermore, lymphocytes from achalasia LES specifically responded to exposure to HSV-1 antigens in vitro as showed by increased proliferation and Th-1 type cytokines release.

CONCLUSIONS

These data suggest that the oligoclonal lymphocytic infiltrate within the LES of achalasia patients may represent the trace of an immune-inflammatory reaction triggered by HSV-1 antigens and that the Th1-type cytokines released by the activated lymphocytes may contribute to establish the neuronal damage accounting for the clinical features of idiopathic achalasia.

Review article: molecular, pathological and therapeutic features of human enteric neuropathies

BACKGROUND

Considerable information has been gathered on the functional organization of enteric neuronal circuitries regulating gastrointestinal motility. However, little is known about the neuropathophysiological mechanisms underlying gastrointestinal motor disorders.

AIM

To analyse the most important pathological findings, clinical implications and therapeutic management of idiopathic enteric neuropathies.

METHODS

PubMed searches were used to retrieve the literature inherent to molecular determinants, pathophysiological bases and therapeutics of gastrointestinal dysmotility, such as achalasia, gastroparesis, chronic intestinal pseudo-obstruction, Hirschsprung's disease and slow transit constipation, to unravel advances on digestive disorders resulting from enteric neuropathies.

RESULTS

Current data on molecular and pathological features of enteric neuropathies indicate that degenerative and inflammatory abnormalities can compromise the morpho-functional integrity of the enteric nervous system. These alterations lead to a massive impairment in gut transit and result in severe abdominal symptoms with associated high morbidity, poor quality of life for patients and established mortality. Many pathophysiological aspects of these severe conditions remain obscure, and therefore treatment options are quite limited and often unsatisfactory.

CONCLUSIONS

This review of enteric nervous system abnormalities provides a framework to better understand the pathological processes underlying gut dysmotility, to translate this knowledge into clinical management and to foster the development of targeted therapeutic strategies.

Variations in inflammation and nerve fiber loss reflect different subsets of achalasia patients

BACKGROUND

Achalasia is a debilitating motility disorder with an unknown etiology. Past research has demonstrated a spectrum of histological findings. The objective of this study was to further characterize the histopathology of achalasia, with attention to subsets of findings that may exist, possibly reflecting different pathogeneses.

MATERIALS AND METHODS

Lower esophageal muscle was obtained during surgery for achalasia (n = 12) or cancer (n = 9). Immunohistochemistry was performed to identify various inflammatory cells and nerve fibers, and grading was done by an expert pathologist. Clinical data were taken from medical records.

RESULTS

There were two subsets of achalasia specimens with different histological findings. Group A (7/12; 58%) had an inflammatory infiltrate in the myenteric plexus consisting primarily of T-lymphocytes. Group B (5/12; 42%) had no such infiltrate and had less myenteric plexus macrophages versus Group A (P = 0.03). The loss of nerve fibers was most evident in the muscularis propria in achalasia as compared to controls (P = 0.01), and this loss was more striking in Group B versus A (P = 0.04). The mean duration of symptoms was 16.6 (A) versus 6.4 years (B) (P = NS).

CONCLUSIONS

Two subsets of achalasia patients exist with different histological findings. Group A had T-cell-rich inflammation present with associated macrophages. Group B, with no inflammation, had greater loss of nerve fibers in the muscularis propria versus Group A, and therefore, may represent more aggressive disease with shorter duration of symptoms. These results suggest that various pathogeneses of achalasia may exist that share a common pathway of aganglionosis.

Achalasia

Achalasia is a rare motor disorder of the oesophagus, characterised by the absence of peristalsis and impaired swallow-induced relaxation. These motor abnormalities result in stasis of ingested food in the oesophagus, leading to clinical symptoms, such as dysphagia, regurgitation of food, retrosternal pain and weight loss. Although it is well demonstrated that loss of myenteric oesophageal neurons is the underlying problem, it still remains unclear why these neurons are preferentially attacked and destroyed by the immune system. This limited insight into pathophysiology explains the fact that treatment is limited to interventions aimed at reducing the pressure of the lower oesophageal sphincter. The most successful therapies are clearly pneumatic dilatation and Heller myotomy with short-term success rates of 70-90%, declining to 50-65% after more than 15 years. The challenge for the coming years will undoubtedly be to get more insight into the underlying disease mechanisms and to develop a treatment to restore function.

Achalasia: physiology and etiopathogenesis

Achalasia is a disorder of esophageal motility that has been well documented for over 300 years. Despite this, the initiating factor or factors and the underlying mechanisms leading to the characteristic features of achalasia, the absence of distal esophageal peristalsis and abnormal lower esophageal sphincter relaxation, are still not well understood. Recent work has shed light on changes in neurotransmission and cell signaling in the lower esophagus and lower esophageal sphincter that lead to achalasia. A number of recent reviews have thoroughly discussed diagnostic and therapeutic modalities and the reader is referred to these for in-depth review of these topics. The focus of this review will be on our current understanding of the physiology of esophageal peristalsis and lower esophageal sphincter function as it relates to achalasia and on available evidence for etiology and proposed pathophysiologic mechanisms.

Laparoscopic Heller myotomy for achalasia

BACKGROUND

Achalasia is an uncommon illness affecting 1 per 100,000 patients yearly. There is evidence to suggest viral, autoimmune, and hereditary etiologies. There are many treatment options available including medications, botulinum toxin injection, pneumatic dilation, and surgical myotomy.

METHODS

We present a retrospective review of patients undergoing laparoscopic-modified Heller myotomy at a large referral and surgical training center.

RESULTS

There were 36 patients identified. Thirty patients had undergone prior treatment with botulinum toxin injection, pneumatic dilation, previous Heller myotomy, or esophageal stenting. Immediate complications included mucosal perforation (2), spleen injury (1), and trocar-site infection (1). There were no postoperative esophageal leaks. Three patients suffered reflux requiring the daily use of a proton pump inhibitor 9 months after surgery. Three patients suffered recurrent dysphagia.

CONCLUSIONS

Presently, there are little data to suggest an ideal management strategy in patients with achalasia. Our patient population consists predominantly of failures of other treatment methods submitted for laparoscopic myotomy. Our data suggest that laparoscopic Heller myotomy can be safely undertaken in this population, without a higher than expected rate of recurrent symptoms or reflux.

The lower oesophageal sphincter

The lower oesophageal sphincter (LOS) is a specialized segment of the circular muscle layer of the distal oesophagus, accounting for approximately 90% of the basal pressure at the oesophago-gastric junction. Together with the crural diaphragm, it functions as an antireflux barrier protecting the oesophagus from the caustic gastric content. During swallowing or belching, the LOS muscle must relax briefly in order to allow passage of food or intragastric air. These swallow-induced and prolonged transient lower oesophageal sphincter relaxations (TLOSRs) respectively result from activation of the inhibitory motor innervation of the sphincter. Both in man and animals, the main neurotransmitter released by the inhibitory neurones is nitric oxide. The two typical examples of dysfunction of the LOS are achalasia and gastro-oesophageal reflux disease (GORD). Achalasia is characterized by reduction or even absence of the inhibitory innervation to the LOS, leading to impaired LOS relaxation with dysphagia and stasis of food in the oesophagus. On the contrary, GORD results from failure of the antireflux barrier, with increased exposure of the oesophagus to gastric acid. This leads to symptoms such as heartburn and regurgitation, and in more severe cases to oesophagitis, Barrett's oesophagus and even carcinoma. To date, TLOSRs are recognized as the main underlying mechanism, and may represent an important target for treatment. More insight in the pathogenesis of both diseases will undoubtedly lead to new treatments in the near future.