The Controversy of Pepsinogen A/Pepsin A in Detecting Extra-Gastroesophageal Reflux.

BACKGROUND: Pepsinogen A (PGA)/pepsin A is often used as a diagnostic marker of extra-gastroesophageal reflux. We aimed to explore whether its positivity in upper aerodigestive tract (UADT) was specific enough to diagnose reflux. METHODS: PGA/pepsin A protein levels were examined in 10 types of tissues and 10 types of body fluid by immunological staining, western blot or Elisa, using three different commercially available brands simultaneously. Liquid chromatography-tandem mass spectrometry parallel reaction monitoring (LC-MS/MS PRM) served as a gold reference for the detection of PGA/pepsin A proteins. PGA gene expression was analyzed by reverse transcriptase sequencing methods for tissue samples. Specifically, 24 hour pH monitoring technique was conducted for patients who donated saliva samples. RESULTS: Eight out of ten types of human tissue samples (stomach, esophagus, lung, kidney, colon, parotid gland, nasal turbinate and nasal polyps) were confirmed positive for PGA/pepsin A gene and protein by genetic and PRM technique, respectively. Two out of ten types of body fluid samples (gastric fluid, urine) were confirmed positive for PGA/pepsin A protein by PRM technique. The consistence rates of PGA/pepsin A positivity among three commercial antibody brands and Elisa kit were poor, and Elisa results of salivary did not match with 24-hour pH monitoring. CONCLUSIONS: Multiple tissues and body fluid could be detected baseline expression levels of PGA/pepsin A gene and protein. However, those commercially available PGA/pepsin A antibodies achieved poor sensitivity and specificity, therefore, relying on the detection of PGA/pepsin A in UADT by single antibodies to diagnose extra-gastroesophageal reflux without a specific positive cut-off value is unreliable.

Single-Cell Transcriptome Profiling Identifies Phagocytosis-Related Dual-Feature Cells in A Model of Acute Otitis Media in Rats.

Background: The molecular mechanisms of acute otitis media (AOM) development, and the intercellular crosstalk within the multicellular ecosystem of AOM, are not clear. Methods: We established a model of AOM in rats (with normal rats as controls) and undertook single-cell RNA sequencing (scRNA-seq) for the middle-ear mucosa (MEM). Cell clustering and trajectory analyses were undertaken using Seurat and Monocle 2 packages in R software. Pathway analyses were done by gene set enrichment analysis (GSEA). Cell-cell interactions were inferred by CellChat. Cell scores were calculated to identify cells with dual-feature. Results: A total of 7023 cells from three samples of inflamed MEM and 5258 cells from three samples of healthy MEM underwent scRNA-seq, which identified 20 cell clusters belonging to eight major cell types. After exposure to lipopolysaccharide, the MEM underwent significant conversion of cell types characterized by rapid infiltration of macrophages and neutrophils. M2 macrophages seemed to play a key part in inflammatory intercellular crosstalk, which facilitated the maintenance and proliferation of macrophages, cell chemotaxis, and regulation of the proinflammatory activities of cytokines. Three rare cell clusters with phagocytosis-related dual-feature were also identified. They coexisted with professional phagocytes in the MEM, and displayed distinct immunoregulatory functions by maintaining a normal immune microenvironment or influencing inflammation progression. Conclusions: Macrophages might be the "master" initiators and regulators of the inflammatory response of the MEM to external stimuli. And their functions are fulfilled by a specific polarization status (M2) and sophisticated intercellular crosstalk via certain signaling pathways. Besides, the coexistence of professional phagocytes and non-professional phagocytes as well as their interplay in the MEM provides new clues for deciphering the underlying pathogenic mechanisms of AOM.

Correlation of pathogenic effects of laryngopharyngeal reflux and bacterial infection in COME of children.

BACKGROUND: Bacteria infection and laryngopharyngeal reflux (LPR) were believed the important pathogenesis of chronic otitis media with effusion (COME). But no study researched the relationship between them on COME. AIMS: To confirm bacterial could arrive middle ear through LPR and produced acid metabolites to activate the pepsinogen of LPR causing COME. MATERIAL AND METHODS: Children (65) diagnosed COME with 122 middle ear effusions were included in COME group. Children (22) with congenital/acquired profound deafness with 22 middle ear lavage were included in CI group. Pepsin A concentration in the effusion and lavage fluid were measured. The DNA of the bacteria, IL-8 and TNF-α in the effusion were detected. RESULTS: The average concentration of pepsin A in the effusions and lavage were 176.65 ± 242.09 and 19 ng/ml. Bacterial infection rates were 75.76% and 24.24% in the pepsin A(+) and pepsin A(-) patients. In the bacterial (+), the patients of pepsin A(+) was 4.33 times higher than those of pepsin A(-). TNF-α in pepsin A(+) was higher than that in pepsin A(-). TNF-α and IL-8 were higher in bacteria(+) than those of bacteria(-). CONCLUSIONS: Bacterial infection and LPR might act in synergy in the pathogenesis of COME. SIGNIFICANCE: First time to propose LPR and bacterial infection might work synergistically to cause COME.

[Changes of endothelial cell function and platelet activation in rabbit spinal cord with ischemia-reperfusion injury].

OBJECTIVE: To study the changes of vascular endothelial cell function and platelet activation in rabbit spinal cord following ischemia-reperfusion (I/R) injury and their roles in the spinal cord injury. METHODS: Rabbit spinal cord I/R injury models were established using Zivin method, and the changes in plasma NO and GMP140 levels were dynamically monitored after the injury. RESULTS: Plasma NO level increased significantly in the I/R group at the end of the ischemia, and reached the peak level at 2 h of reperfusion as compared to that in sham-operated group (P<0.01). Plasma NO level decreased at 6 h of reperfusion, but still significantly higher than the level in the sham-operated group (P<0.05). Plasma GMP140 underwent no significant changes in the sham-operated group, but significantly increased in the I/R group at the end of the ischemia, followed by gradual declination to the normal level at 2 h of reperfusion. CONCLUSION: Spinal cord I/R injury causes overexpressions of NO and GMP140, suggesting the involvement of endothelial cell injury and platelet overactivation in the pathological process and repair of spinal cord I/R injury.