Differential Neurogenesis Status Among Achalasia Subtypes

Achalasia is an acquired esophageal neurodegenerative disorder, characterized by selective loss of inhibitory neurons in the myenteric plexus of the lower esophageal sphincter (LES). The Enteric neural precursor cell (ENPC) is essential in maintaining neurogenesis, but its role in achalasia pathogenesis is unknown. This study aimed to explore the neurogenesis status in the LES among achalasia patients. LES specimens from 59 patients with achalasia who underwent peroral endoscopic myotomy (POEM) and from 19 controls with esophageal cancer were examined. Double-labeled immunofluorescence staining was performed to evaluate Nestin-expressing ENPC and axonal innervation in the LES. Immunofluorescence values were compared between groups and correlated with clinical variables, including demographics, disease duration, Eckardt score, manometric parameters, and treatment outcome. A significant reduction of Nestin-positive cells, PGP9.5- and nNOS-labeled axon innervation was observed in achalasia. The number of Nestin-positive cells significantly correlated with axon innervation, confirming their roles in neurogenesis. The number of Nestin-positive cells, immature total axons (Nestin+PGP9.5+) and immature nitrergic axons (Nestin+nNOS+) were different among achalasia subtypes. Type 2 achalasia exhibited a more severe loss of both ENPC and axon innervation, while type 1 achalasia was characterized by retained ENPC and immature nitrergic axons, but with severe depletion of mature axons (Nestin-nNOS+). Neurogenesis is generally impaired in achalasia; however, the status of neurogenesis varies across different manometric subtypes, suggesting that the pathophysiology of each subtype may be distinct.