Hydrogen sulfide synthesis enzymes reduced in lower esophageal sphincter of patients with achalasia.

The etiology of achalasia remains largely unknown. Considerable evidence reveals that the lower esophageal sphincter dysfunction is due to the lack of inhibitory neurotransmitter, secondary to esophageal neuronal inflammation or loss. Recent studies suggest hydrogen sulfide may act as an inhibitory transmitter in gastrointestinal tract, but study about hydrogen sulfide in human esophagus still lack. The aim of the study was to investigate if hydrogen sulfide synthesis enzymes could be detected in human esophagus and if the synthesis of the endogenous hydrogen sulfide could be affected in achalasia patients. Tissue samples in cardia, lower esophageal sphincter, 2 cm and 4 cm above lower esophageal sphincter were obtained from achalasia patients undergoing peroral endoscopic myotomy. Control tissues in lower esophageal sphincter were obtained from esophageal carcinoma patients. Expression of cystathionine-β-synthase and cystathionine-γ-lyase in lower esophageal sphincter of achalasia patients and control were detected by immunohistochemical staining. In addition, expression of cystathionine-β-synthase and cystathionine-γ-lyase were compared among different parts of esophagus in achalasia patients. Compared with control, the expression of cystathionine-β-synthase and cystathionine-γ-lyase in lower esophageal sphincter of achalasia patients was significantly reduced (χ2 = 11.429, P = 0.010). The expression of cystathionine-β-synthase and cystathionine-γ-lyase were lower in lower esophageal sphincter than that in 2 cm and 4 cm above lower esophageal sphincter, respectively (all P < 0.05). In conclusion, the expression of hydrogen sulfide synthesis enzymes, cystathionine-β-synthase and cystathionine-γ-lyase, can be detected in human esophagus and is reduced in patients with achalasia, which implicates the involvement of the two hydrogen sulfide synthesis enzymes in the pathophysiology of achalasia.