Endogenous Hydrogen Sulfide Contributes to Tone Generation in Porcine Lower Esophageal Sphincter Via Na+/Ca2+ Exchanger

A Predictive Nomogram for the Occurrence of Gastroesophageal Reflux Disease After Sleeve Gastrectomy: A Study Based on Preoperative HERM

Purpose

Gastroesophageal reflux disease (GERD) is a common complication after laparoscopic sleeve gastrectomy (LSG); This study aimed to construct a model that can predict the incidence of GERD after LSG by exploring the correlation between the results of high-resolution esophageal manometry (HREM) and the incidence of GERD after LSG.

Patients and Methods

We collected the clinical data of patients who had undergone HREM before bariatric surgery from September 2013 to September 2019 at the bariatric center of our hospital. The Gerd-Q scores during the postoperative follow-up were collected to determine the incidence of GERD. A logistic regression analysis was performed to explore the correlation of the HREM results and general clinical data with the incidence of GERD after LSG.

Results

The percentage of synchronous contractions, lower esophageal sphincter (LES) resting pressure, and history of smoking were correlated with the development of GERD after LSG, with the history of smoking and percentage of synchronous contractions as risk factors and LES resting pressure as a protective factor. The training set showed an area under the ROC curve (AUC) of the nomogram model of 0.847. The validation set showed an AUC of 0.761. The decision and clinical impact curves showed a high clinical value for the prediction model.

Conclusion

The HREM results correlated with the development of GERD after LSG, with the percentage of synchronous contractions and LES resting pressure showing predictive value. Combined with the history of smoking, the predictive model showed a high confidence and clinical value.

Effects of hydrogen sulfide on relaxation responses in the lower esophageal sphincter in rabbits: the potential role of potassium channels

Hydrogen sulfide (H2S) is a significant physiologic inhibitory neurotransmitter. The main goal of this research was to examine the contribution of diverse potassium (K+) channels and nitric oxide (NO) in mediating the H2S effect on electrical field stimulation (EFS)-induced neurogenic contractile responses in the lower esophageal sphincter (LES). EFS-induced contractile responses of rabbit isolated LES strips were recorded using force transducers in organ baths that contain Krebs-Henseleit solutions (20 ml). Cumulative doses of NaHS, L-cysteine, PAG, and AOAA were evaluated in NO-dependent and NO-independent groups. The experiments were conducted again in the presence of K+ channel blockers. In both NO-dependent and NO-independent groups, NaHS, L-cysteine, PAG, and AOAA significantly reduced EFS-induced contractile responses. In the NO-dependent group, the effect of NaHS and L-cysteine decreased in the presence of 4-AP, and also the effect of NaHS decreased in the NO-dependent and independent group in the presence of TEA. In the NO-independent group, K+ channel blockers didn't change L-cysteine-induced relaxations. K+ channel blockers had no impact on the effects of PAG and AOAA. In addition, NaHS significantly relaxed 80-mM KCl-induced contractions, whereas L-cysteine, PAG, and AOAA did not. In the present study, H2S decreased the amplitudes of EFS-induced contraction responses. These results suggest that Kv channels and NO significantly contribute to exogenous H2S and endogenous H2S precursor L-cysteine inhibitory effect on lower esophageal sphincter smooth muscle.

Pharmacological Inhibition of Endogenous Hydrogen Sulfide Attenuates Breast Cancer Progression

Hydrogen sulfide (H₂S), a gaseous signaling molecule, is associated with the development of various malignancies via modulating various cellular signaling cascades. Published research has established the fact that inhibition of endogenous H₂S production or exposure of H₂S donors is an effective approach against cancer progression. However, the effect of pharmacological inhibition of endogenous H₂S-producing enzymes (cystathionine-γ-lyase (CSE), cystathionine-β-synthase (CBS), and 3-mercaptopyruvate sulfurtransferase (3-MPST)) on the growth of breast cancer (BC) remains unknown. In the present study, DL-propargylglycine (PAG, inhibitor of CSE), aminooxyacetic acid (AOAA, inhibitor of CBS), and L-aspartic acid (L-Asp, inhibitor of 3-MPST) were used to determine the role of endogenous H₂S in the growth of BC by in vitro and in vivo experiments. An in silico study was also performed to confirm the results. Corresponding to each enzyme in separate groups, we treated BC cells (MCF-7 and MDA-MB-231) with 10 mM of PAG, AOAA, and L-Asp for 24 h. Findings reveal that the combined dose (PAG + AOAA + L-Asp) group showed exclusive inhibitory effects on BC cells’ viability, proliferation, migration, and invasion compared to the control group. Further, treated cells exhibited increased apoptosis and a reduced level of phospho (p)-extracellular signal-regulated protein kinases such as p-AKT, p-PI3K, and p-mTOR. Moreover, the combined group exhibited potent inhibitory effects on the growth of BC xenograft tumors in nude mice, without obvious toxicity. The molecular docking results were consistent with the wet lab experiments and enhanced the reliability of the drugs. In conclusion, our results demonstrate that the inhibition of endogenous H₂S production can significantly inhibit the growth of human breast cancer cells via the AKT/PI3K/mTOR pathway and suggest that endogenous H₂S may act as a promising therapeutic target in human BC cells. Our study also empowers the rationale to design novel H₂S-based anti-tumor drugs to cure BC.

Physiological roles of hydrogen sulfide in mammalian cells, tissues and organs

H2S belongs to the class of molecules known as gasotransmitters, which also includes nitric oxide (NO) and carbon monoxide (CO). Three enzymes are recognized as endogenous sources of H2S in various cells and tissues: cystathionine g-lyase (CSE), cystathionine β-synthase (CBS) and 3-mercaptopyruvate sulfurtransferase (3-MST). The current article reviews the regulation of these enzymes as well as the pathways of their enzymatic and non-enzymatic degradation and elimination. The multiple interactions of H2S with other labile endogenous molecules (e.g. NO) and reactive oxygen species are also outlined. The various biological targets and signaling pathways are discussed, with special reference to H2S and oxidative posttranscriptional modification of proteins, the effect of H2S on channels and intracellular second messenger pathways, the regulation of gene transcription and translation and the regulation of cellular bioenergetics and metabolism. The pharmacological and molecular tools currently available to study H2S physiology are also reviewed, including their utility and limitations. In subsequent sections, the role of H2S in the regulation of various physiological and cellular functions is reviewed. The physiological role of H2S in various cell types and organ systems are overviewed. Finally, the role of H2S in the regulation of various organ functions is discussed as well as the characteristic bell-shaped biphasic effects of H2S. In addition, key pathophysiological aspects, debated areas, and future research and translational areas are identified A wide array of significant roles of H2S in the physiological regulation of all organ functions emerges from this review.

Involvement of different receptor subtypes in prostaglandin E2-induced contraction and relaxation in the lower esophageal sphincter and esophageal body

Prostaglandin E₂ (PGE₂) plays a role in the pathogenesis of gastro-esophageal reflux disease (GERD). There are 4 subtypes of PGE₂, PGE₂ receptor 1, 2, 3 and 4 (EP 1-4). In GERD patents, PGE₂, EP2 and EP4 are upregulated. However, the effects of PGE2 on esophageal motility remain elusive. We examined how PGE₂ regulates motility in the porcine circular smooth muscle of the lower esophageal sphincter (LES), and the circular and longitudinal smooth muscle of the esophagus body in organ bath. PGE₂ induced tonic relaxation in the LES and circular smooth muscle, but transient contraction in longitudinal smooth muscle. The relaxation of the LES and circular smooth muscle was similar in pattern and mechanism, but was much larger in the LES. The relaxation was completely blocked by a voltage-gated K⁺ channel blocker or 40 mM K⁺ depolarization, indicating the involvement of K⁺ channel. Longitudinal smooth muscle contraction was completely blocked by an L-type Ca²⁺ channel blocker, showing the contribution of Ca²⁺ movement. The involvement of the EP receptor in motility was examined with selective receptor agonists and antagonists. Activation of EP2 and EP4 caused relaxation in the LES and circular smooth muscle. Compatible with PGE₂, EP2 and EP4 agonists caused more significant relaxation in the LES than in circular smooth muscle. EP1 contributed to the longitudinal smooth muscle contraction. The different effects of PGE₂ in the LES, circular and longitudinal smooth muscle contributes to esophageal motility, their impairment might increase the amount and frequency of esophageal reflux.