A bama minipig model of laryngopharyngeal reflux and the change of laryngopharyngeal mucosal ultrastructure

A Novel Laryngopharyngeal Reflux Disease Model for Bama Pigs

OBJECTIVE

To develop a novel Laryngopharyngeal Reflux Disease (LPRD) model in Bama pigs through endoscopic cricopharyngeal myotomy.

METHODS

A total of eight 8-month-old Bama pigs were randomly assigned to either the control or surgery group. Prior to intervention, upper esophageal sphincter (UES) manometry and laryngopharyngeal Dx-pH monitoring were conducted to establish baseline physiological parameters for each pig. Subsequently, the surgery group underwent endoscopic cricopharyngeal myotomy, while the control group did not. Two weeks postintervention, these procedures were repeated to evaluate changes in UES contractility and the occurrence of reflux events. At week eight postsurgery, mucosal tissues from both groups were harvested for histological analysis. Hematoxylin and eosin (H&E) staining was used to assess inflammation, while transmission electron microscopy (TEM) examined alterations in intercellular spaces and desmosomes.

RESULTS

The mean UES pressures in the control and surgery groups were 59 ± 9 mmHg and 68 ± 12 mmHg, respectively. In the surgery group, there was a significant decrease in UES pressure 2weeks after the operation compared to preoperative values (P = 0.005), whereas no significant change was observed in the control group (P = 0.488). Laryngopharyngeal reflux (LPR) was successfully induced in the surgery group as evidenced by reflux events with pH <5.0, which were not detected in the control group. HE staining revealed marked inflammatory cell infiltration and submucosal gland expansion in throat tissues of the surgery group Bama pigs. TEM further showed enlarged intercellular spaces and reduced desmosome numbers in the laryngopharyngeal epithelium compared to controls.

CONCLUSION

Given analogous throat epithelial structures to humans, Bama pigs are an appropriate species for an LPRD animal model. Endoscopic cricopharyngeal myotomy effectively induces LPR and observable pathological changes in Bama pigs, providing a valuable platform for further research into LPRD pathophysiology.

Poor consistency between reflux symptom index and laryngopharyngeal pH monitoring in laryngopharyngeal reflux diagnosis in Chinese population

Background

It is unknown whether the reflux symptom index (RSI) can replace pH monitoring as a diagnostic tool for laryngopharyngeal reflux (LPR) in Chinese people. The relationships between reflux parameters and LPR symptoms also require further research.

Methods

A total of 216 Chinese patients underwent laryngopharyngeal pH monitoring and filled out an RSI questionnaire. Laryngopharyngeal pH monitoring indicated a diagnosis of LPR for patients with 7 or more episodes of reflux or a reflex area index (RAI) of 6.3 or more. The RSI questionnaire indicated a diagnosis of LPR for patients with RSI scores of 14 or higher.

Results

Of the 216 patients, 85 were diagnosed with LPR as assessed by the RSI, and 72 were diagnosed with LPR through laryngopharyngeal pH monitoring. The Cohen's kappa coefficient comparing LPR diagnosis consistency between RSI score and laryngopharyngeal pH monitoring was 0.133 (P=0.007). This indicated the two diagnostic methods were consistent to a low degree; the total consistency rate was only 59.7% (129/216). The sensitivity of the RSI was 48.6% (35/72), and its specificity was 82.5% (94/114). For convenience, we named the nine symptom groups in the RSI sequentially as P1-P9. P1, P2, P3, P5, P6, and P7 were all correlated with at least one reflux parameter (P<0.05), but P4, P8, and P9 were not correlated with any reflux parameters (P>0.05). A total of 72 patients were diagnosed using pH monitoring, the gold standard for LPR diagnosis. The most common symptoms of LPR were found to be P9, P3, P8, P7, and P2 in these patients. The symptoms that most seriously affected patients were P9, P8, P3, P7, and P2.

Conclusions

The consistency in diagnosis of LPR between the RSI and laryngopharyngeal pH monitoring was poor, meaning the RSI is not a suitable LPR initial screening tool and cannot replace pH monitoring. Additionally, reflux symptoms P4, P8, and P9 were not correlated with any reflux parameters. The most prevalent LPR symptom was P9, followed by P3, P8, P7, and P2. The most severe symptom was also P9, followed by P8, P3, P7, and P2.

The Relationship Between Gastroesophageal Reflux Disease and Laryngopharyngeal Reflux Based on pH Monitoring

OBJECTIVES

Many studies on the relationship between gastroesophageal reflux disease (GERD) and laryngopharyngeal reflux (LPR) were based on symptoms, but there are few research on it using reflux monitoring. This study was designed to investigate the relationship between GERD and LPR based on pH monitoring.

METHODS

All patients were scheduled for esophageal manometry and pH monitoring sequentially. They were stratified into 4 groups as no reflux disease, isolated GERD, isolated LPR (iLPR), and GERD combined with LPR (GERD&LPR) according to pH monitoring.

RESULTS

The incidence of LPR in GERD was 46.3%, while the probability of combining GERD in LPR was 52.7%. The reflux profile in the laryngopharynx showed a significant difference in the total reflux time (17.82 ± 18.4 vs 9.62 ± 9.58, P = .023) and the percentage of total reflux time (1.31% ± 1.37% vs 0.71% ± .0.73%, P = .023) between the GERD&LPR and iLPR groups.

CONCLUSION

Laryngopharyngeal reflux can be combined with GERD or it can exist as an independent diagnosis. In patients with GERD&LPR, the total reflux time and the percentage of reflux time in the laryngopharynx are higher than those in the iLPR group. Reflux episodes in the laryngopharynx of patients with GERD&LPR may be derived from GERD.

Histological and anatomical structure of the nasal cavity of Bama minipigs

Objective

The nasal mucosa is equipped with abundant lymphatic tissues, serving as the first line of defense against invasion by microorganisms. In this study, we characterized the features of the nasal mucosa of Bama minipigs (Sus scrofa domestica) via histological analysis.

Methods

Five cross sections (I, II, III, IV, and V) were obtained from the distal end of the nasal cavity toward the pharynx (along the cavity axis) and examined. Specifically, CD3⁺ T cells, immunoglobulin A (IgA)⁺ cells, and M cells were detected by immunohistochemistry, while dendritic cells (DCs) were detected by immunofluorescence. The distribution of goblet cells was determined by periodic acid-Schiff (PAS) staining.

Results

The nasal cavity of Bama minipigs can be divided into three parts: the regio vestibularis (I, II), regio respiratoria (III, IV), and regio olfactoria (V). Lymphoid tissue was present at random locations in the nasal cavity. Abundant lymphoid tissue was located in the roof of the nasopharyngeal meatus and was continuous with the lymphoid tissue of the pharynx. The distribution of CD3⁺ T cells, IgA⁺ cells, M cells, and DCs increased distally in the nasal cavity.

Conclusions

The present work comprises a histological study of the nasal cavity of Bama minipigs, and will be beneficial for understanding the mechanisms of immunity in these animals after nasal vaccination.