Innate Immune Response of the Pig Laryngeal Mucosa to Endotracheal Intubation

Objective

The aim of this study was to measure the effects of endotracheal intubation on innate immune response within the pig laryngeal mucosa.

Study Design

Prospective controlled basic science study.

Setting

The animal experiments and analyses were conducted at the University of Bristol.

Samples and Methods

Eighteen pigs, matched at the major histocompatibility complex (MHC), were used in the study. The pigs were divided into 9 pairs. One of each pair (9 pigs in total) was intubated with an endotracheal tube under general anesthesia for 90 minutes. Two days later, pinch biopsies were taken from the supraglottis (specifically the false cords) and subglottis of both pigs. The experiment was repeated 8 more times. Based on quantitative immunohistochemistry, percentage areas of positive staining for CD172a, CD163, MHC class II, CD14, and CD16 were calculated separately for the epithelium and lamina propria of each biopsy.

Results

Total areas of laryngeal mucosa (epithelium and lamina propria) expressing CD172a and coexpressing CD163 and CD172a were significantly reduced at 2 days following endotracheal intubation ( P = .039 and P = .037, respectively). MHC class II expression and MHC class II coexpression with CD172a were similarly reduced following intubation ( P = .003 and P = .005, respectively). In the supraglottis, MHC class II coexpression with CD16 and CD14 was also reduced following endotracheal intubation ( P = .037).

Conclusions

Our results indicate that endotracheal intubation reduces the number of innate immune cells within the upper airway mucosa. This may be an important first step in a cascade leading to chronic wound and scar formation causing airway stenosis.

The development and treatment of periprosthetic leakage after prosthetic voice restoration. A literature review and personal experience part I: the development of periprosthetic leakage

In the past 30 years, the use of a voice prosthesis has become the treatment of choice for the restoration of speech following laryngectomy. Not only is the placement of a voice prosthesis a simple surgical procedure, but it is also associated with a low rate of complications and an excellent success rate. Approximately, 20-30 % of all patients with voice prostheses, however, develop periprosthetic leakage with aspiration over time. Periprosthetic leakage is usually caused by an enlargement of the tracheo-oesophageal fistula and substantially affects the quality of life of the patients concerned. In a retrospective analysis of our patients, the incidence of periprosthetic leakage was 35.7 % in a total of 232 patients who underwent laryngectomy during a period of 20 years. Substantial enlargement of the tracheo-oesophageal fistula which required multiple treatments occurred in 12.5 % of the patients. In this review, the various causes of fistula enlargement are discussed on the basis of the literature and the experience that we have accumulated during the past 20 years in the management of patients with voice prostheses.

What role do mucins have in the development of laryngeal squamous cell carcinoma? A systematic review

Mucins are the dominant component in the protective mucus layer on mucosal surfaces including the larynx. Hence, they are part of the first line of defence against external stimuli including effect of smoking in the larynx. We asked whether existing published evidence supported the hypothesis that alteration in mucins expression/production is related to the laryngeal neoplastic process. The objective of this study is to review published evidence for mucins having an important role in normal laryngeal physiology and the development of laryngeal squamous cell carcinoma (SCC). We aimed to review all available literature on mucins in the larynx in order to develop hypotheses to be tested by future research. Thereby, new potential means of prevention and treatment of laryngeal cancer may be developed. A systematic search of all published literature was conducted. Systematic searches were done in the following databases: AMED, BNI, EMBASE, HMIC, MEDLINE, PsycINFO, CINAHL and HEALTH BUSINESS ELITE from their respective inception up to 11 February 2011. The following keywords were used in combination: mucin, larynx and squamous cell carcinoma. Altogether, 53 studies were identified; 43 studies were excluded following screening of the titles and abstracts. Full text manuscripts for ten studies were obtained for detailed evaluation and five studies were included in this review. No single study fulfilled all relevant criteria. Based on the included studies, we now know that MUC1 is definitely expressed in SCC larynx. However, there is no definitive evidence to suggest that MUC1 and MUC2 are aberrantly expressed in SCC larynx as compared to normal larynx. Further studies using the best available detection technique to detect MUC1, MUC2 and other possible relevant mucins i.e., MUC4 on adequate numbers of normal and SCC specimens are needed to confirm the findings of this review.

[Prosthetic voice restoration after laryngectomy: the management of fistula complications with anti-reflux medications]

INTRODUCTION

Approximately 30% of all patients show periprosthetic leakage or severe fistula enlargement after laryngectomy and prosthetic voice restoration. In a prospective study, we investigated the role of aggressive anti-reflux therapy in fistula complications.

PATIENTS AND METHODS

A total of 48 patients were assigned to one of two groups. Group A consisted of 16 patients with recurrent periprosthetic leakage. Group B comprised 32 patients without periprosthetic leakage. The presence of reflux was objectively assessed using 24-h dual-probe pH monitoring. All patients with pathological reflux underwent proton pump inhibitor (PPI) therapy. After 6 months, patients were re-evaluated for fistula complications and objective reflux parameters.

RESULTS

The mean absolute number of reflux events was 202.8 (+/-44) before and 74.5 (+/-22.9) after PPI therapy (p=0.025). The reflux area index decreased from 419.5 (+/-112.5) before treatment to 105.8 (+/-54.7) after treatment (p=0.0005). The mean DeMeester score was 104.4 (+/-21.3) without PPIs and 43.5 (+/-9.3) after 6 months with PPIs (p=0.028). A risk analysis for patients with both periprosthetic leakage and pathological reflux (15 patients at the beginning of the study, four patients after therapy) showed that the relative risk of periprosthetic leakage decreased to 0.3 (p=0.0054) with PPI therapy.

CONCLUSION

Patients with recurrent periprosthetic leakage in the region of the fistula showed a significantly higher number of supra-oesophageal reflux episodes. Rigorous anti-reflux treatment can help manage or prevent leakage problems in a large proportion of patients.

E-cadherin and transglutaminase-1 epithelial barrier restoration precedes type IV collagen basement membrane reconstruction following vocal fold mucosal injury

The vocal fold epithelium is critical to upper airway immunologic defense and water/ion transport; therefore, any form of physical trauma or insult increases the vulnerability of this structure to functional impairment and pathogen invasion/infection. In this study, we examined the reestablishment of epithelial and basement membrane barrier structures in a well-established rat model of vocal fold mucosal injury. We observed active cell recruitment culminating in peak hyperplasia at 3 days postinjury, the establishment of robust E-cadherin+ and transglutaminase-1+ biochemical barrier signals along the epithelial surface by 3 days postinjury, and the persistent absence of a type IV collagen+ basement membrane at 7 days postinjury. The distinct spatial and temporal immunoactivity of these molecules is consistent with a programmed repair process driving the restoration of vocal fold mucosal integrity and permeability. These data may inform future efforts to optimize functional mucosal recovery postinjury and avoid undesirable events such as barrier compromise or epithelial metaplasia.