Usefulness of pepsin saliva measurement for the detection of primary burning mouth syndrome related to reflux.

OBJECTIVES: To study the diagnostic value of salivary pepsin tests for detecting laryngopharyngeal reflux (LPR) in patients with primary burning mouth syndrome (BMS). METHODS: Patients with BMS and asymptomatic individuals were consecutively recruited from September 2018 to June 2023. Patients underwent hypopharyngeal-esophageal impedance pH-monitoring (HEMII-pH) and saliva collections to measure pepsin. Stomatology evaluation was carried out to exclude other causes of BMS. Oral, pharyngeal and laryngeal signs and symptoms were evaluated with Reflux Sign Assessment (RSA) and Reflux Symptom Score (RSS). Sensitivity, specificity, positive (PPV) and negative (NPV) predictive values of pepsin test were calculated considering the highest values of pepsin tests at ≥ 16, ≥ 36, and ≥ 100 ng/mL cutoffs. Receiver operating characteristic curve (ROC) was evaluated. RESULTS: Forty-nine patients with both BMS and LPR at the HEMII-pH and 21 asymptomatic individuals were recruited. Pepsin test was 83.7%, 79.6%, and 71.4% sensitive at cutoffs ≥ 16, ≥ 36, and ≥ 100 ng/mL, respectively. The ROC analysis reported that a threshold of ≥ 21.5 ng/mL was associated with sensitivity, specificity, PPV and NPV of 81.6%, 81.0%, 90.1% and 65.4%, respectively. The severity score of burning mouth symptom was significantly associated with the saliva pepsin concentration (rs = 0.263; p = 0.029) and the oral RSA (rs = 0.474; p = 0.007). CONCLUSION: Pepsin test is a valuable diagnostic approach for detecting LPR in patients with BMS. Patients with high level of saliva pepsin reported more severe burning mouth symptoms. Future studies are needed to confirm the role of LPR in the primary BMS.

Predicting ventilator-associated pneumonia in elderly patients requiring mechanical ventilation through the detection in tracheal aspirates.

OBJECTIVE: In this study, we evaluated the clinical utility of tracheal aspirates α-amylase (AM), pepsin, and lipid-laden macrophage index (LLMI) in the early diagnosis of ventilator-associated pneumonia (VAP) in elderly patients on mechanical ventilation. METHODS: Within 96 hours of tracheal intubation, tracheal aspirate specimens were collected from elderly patients on mechanical ventilation; AM, pepsin, and LLMI were detected, and we analyzed the potential of each index individually and in combination in diagnosing VAP. RESULTS: Patients with VAP had significantly higher levels of AM, pepsin, and LLMI compared to those without VAP (P < 0.001), and there was a positive correlation between the number of pre-intubation risk factors of aspiration and the detection value of each index in patients with VAP (P < 0.001). The area under a receiver operating characteristic (ROC) curve (AUC) of AM, pepsin, and LLMI in diagnosis of VAP were 0.821 (95% CI:0.713-0.904), 0.802 (95% CI:0.693-0.892), and 0.621 (95% CI:0.583-0.824), the sensitivities were 0.8815, 0.7632, and 0.6973, the specificities were 0.8495, 0.8602, and 0.6291, and the cutoff values were 4,321.5 U/L, 126.61 ng/ml, and 173.5, respectively. The AUC for the combination of indexes in diagnosing VAP was 0.905 (95% CI:0.812-0.934), and the sensitivity and specificity were 0.9211 and 0.9332, respectively. In the tracheal aspirate specimens, the detection rate of AM ≥ cutoff was the highest, while it was the lowest for LLMI (P < 0.001). The detection rates of AM ≥ cutoff and pepsin ≥ cutoff were higher within 48 hours after intubation than within 48-96 hours after intubation (P < 0.001). In contrast, the detection rate of LLMI ≥ cutoff was higher within 48-96 hours after intubation than within 48 hours after intubation (P < 0.001). The risk factors for VAP identified using logistic multivariate analysis included pre-intubation aspiration risk factors (≥3), MDR bacteria growth in tracheal aspirates, and tracheal aspirate AM ≥ 4,321.5 U/L, pepsin ≥ 126.61 ng/ml, and LLMI ≥ 173.5. CONCLUSION: The detection of AM, pepsin, and LLMI in tracheal aspirates has promising clinical utility as an early warning biomarker of VAP in elderly patients undergoing mechanical ventilation.

Papain-Based Solubilization of Decellularized Extracellular Matrix for the Preparation of Bioactive, Thermosensitive Pregels.

Solubilized, gel-forming decellularized extracellular matrix (dECM) is used in a wide range of basic and translational research and due to its inherent bioactivity can promote structural and functional tissue remodeling. The animal-derived protease pepsin has become the standard proteolytic enzyme for the solubilization of almost all types of collagen-based dECM. In this study, pepsin was compared with papain, α-amylase, and collagenase for their potential to solubilize porcine liver dECM. Maximum preservation of bioactive components and native dECM properties was used as a decisive criterion for further application of the enzymes, with emphasis on minimal destruction of the protein structure and maintained capacity for physical thermogelation at neutral pH. The solubilized dECM digests, and/or their physically gelled hydrogels were characterized for their rheological properties, gelation kinetics, GAG content, proteomic composition, and growth factor profile. This study highlights papain as a plant-derived enzyme that can serve as a cost-effective alternative to animal-derived pepsin for the efficient solubilization of dECM. The resulting homogeneous papain-digested dECM preserved its thermally triggered gelation properties similar to pepsin digests, and the corresponding dECM hydrogels demonstrated their enhanced bioadhesiveness in single-cell force spectroscopy experiments with fibroblasts. The viability and proliferation of human HepaRG cells on dECM gels were similar to those on pure rat tail collagen type I gels. Papain is not only highly effective and economically attractive for dECM solubilization but also particularly interesting when digesting human-tissue-derived dECM for regenerative applications, where animal-derived materials are to be avoided.

Association between oropharyngeal ph-monitoring, pepsin saliva concentration and degree of apnea-hypopnea index of obstructive sleep apnea.

OBJECTIVE: To investigate the association between obstructive sleep apnea (OSA) and laryngopharyngeal reflux (LPR) through oropharyngeal pH-monitoring and pepsin saliva measurements. DESIGN: Prospective uncontrolled study. METHODS: Patients with sleep disturbances and reflux symptoms underwent polysomnography, 24-h oropharyngeal pH-monitoring and saliva pepsin collections. The prevalence of LPR was investigated in OSA patients according to oropharyngeal pH-monitoring and pepsin measurements. A correlation analysis was performed between pH-monitoring findings, pepsin saliva levels, reflux symptom score-12 (RSS-12), reflux sign assessment (RSA), Apnea-Hypopnea Index (AHI), Epworth Sleepiness Scale, Pichot and arousal findings. RESULTS: Thirty-seven patients completed the evaluations. LPR was detected in 34/37 (92%) and 29/34 (85%) patients at the oropharyngeal-pH monitoring and pepsin test, respectively. OSA was detected in 30 patients (81%). Among them, LPR was detected in 28/30 (93%) cases. Pharyngeal reflux events mainly occurred nighttime/supine in OSA patients. Both Ryan score and supine reflux time at pH < 6.5 were significantly associated with BMI and the RSA sub- and total scores (p < 0.02). Tongue-base hypertrophy score was positively associated with the number of micro-arousals (p = 0.027); the supine percent of pH < 6.5 (p = 0.030); morning (p = 0.030) and bedtime pepsin saliva measurements (p = 0.037). The bedtime pepsin saliva level was significantly associated with Ryan Score (p = 0.047); AHI (p = 0.017) and the sleep saturation < 90% time (p = 0.040). The saliva level of the morning pepsin was associated with a shortest paradoxical sleep phase (p = 0.013). CONCLUSION: OSA patients may have high prevalence of pharyngeal reflux events at the oropharyngeal pH-monitoring and high pepsin saliva measurements. Oropharyngeal pH-monitoring should be useful for the correlation between reflux and sleep findings in OSA patients. Future large cohort controlled studies are needed to determine the prevalence of LPR in OSA and healthy individuals.

Saliva pepsin measurements in the detection of gastroesophageal reflux disease in laryngopharyngeal reflux patients: a cohort study.

OBJECTIVE: To study the diagnostic value of salivary pepsin measurement (Peptest) for detecting gastroesophageal reflux disease (GERD) in laryngopharyngeal reflux (LPR) patients. METHODS: Patients with reflux symptoms were consecutively recruited from January 2020 to November 2022. Patients benefited from hypopharyngeal-esophageal impedance-pH monitoring (HEMII-pH), fasting and bedtime saliva collections to measure pepsin. Sensitivity, specificity, positive (PPV) and negative (NPV) predictive values were evaluated for GERD and LPR patients considering the highest values of pepsin tests at ≥ 16, ≥ 75, and ≥ 216 ng/mL cutoffs. The relationship between HEMII-pH, endoscopic and clinical findings, and pepsin measurements was studied. RESULTS: Saliva was collected in 109 LPR patients and 30 individuals with both LPR and GERD. The total number of pharyngeal reflux events was significantly higher in GERD-LPR patients compared with LPR patients (p = 0.008). The mean fasting and bedtime pepsin saliva concentrations were similar between groups. The sensitivity of Peptest in LPR patients was 30.5%, 70.2%, and 84.0% at cutoffs ≥ 16, ≥ 75 and ≥ 216 ng/mL. In GERD-LPR group, Peptest was 80.0%, 70.0%, and 30.0% sensitive. At cutoff 16 ng/mL, Peptest reported PPV of 20.7% and 94.8% in LPR-GERD and LPR groups, respectively. NPV were 73.9% and 8.7% in GERD-LPR and LPR groups, respectively. The consistency analysis between Peptest and HEMII-pH was not significant. Peptest was significantly associated with the number of acid pharyngeal reflux events (rs = 0.182; p = 0.032). CONCLUSION: Pepsin saliva measurements appear to be not a reliable diagnostic tool for the detection of GERD in LPR patients. Future studies are needed to determine the place of Peptest in laryngopharyngeal reflux and gastroesophageal reflux diseases.

SPECIFIC FEATURES OF THE ORAL MICROBIOME IN YOUNG CHILDREN WITH ARYNGOPHARYNGEAL REFLUX AND ITS ROLE THE DEVELOPMENT OF RECURRENT RESPIRATORY DISEASES.

OBJECTIVE: The aim: To examine the composition of the oral microbiome in young children with laryngopharyngeal reflux (LPR) and its role the development of recurrent respiratory diseases. PATIENTS AND METHODS: Materials and methods: There were examined 38 children with physiological gastroesophageal reflux (GER), 18 children with LPR who had a medical history of recurrent bronchitis and 17 healthy children (control group). The study included the collection of anamnesis, objective examination. The qualitative and quantitative microbial composition of the upper respiratory tract was performed obtained by oropharyngeal deep swab. Salivary pepsin level and IL-8 were determined by enzyme-linked immunosorbent assay. RESULTS: Results: This research showed significant alterations in the oral microbiome of patients with GER and LPR as compared to healthy control. We found that gram-negative microbiota such as Klebsiella pneumoniae, Escherichia coli, Proteus vulgaris, Proteus spp. and Candida albicans were identified in children with GER and LPR compared to the healthy control. At the same time, the amount of such a representative of the normal microbiome as Streptococcus viridans in children with LPR was sharply reduced. There were established a much higher mean salivary pepsin level of the patients with LPR than in the GER and control group. We found the association between high pepsin levels, saliva IL-8 levels and frequency of respiratory pathology in children with LPR. CONCLUSION: Conclusions: Our study confirms that increased levels of pepsin in saliva are a risk factor for recurrent respiratory diseases in children with LPR.

[Consistency analysis of pepsin immunohistochemistry and pepsin test box in the diagnosis of laryngopharyngeal reflux].

Objective:To analyze the consistency of pepsin assay kit, pepsin IHC, reflux symptom index（RSI） and reflux finding score（RFS） in the diagnosis of laryngopharyngeal reflux disease（LPRD）. Methods:The clinical data of 61 inpatients with laryngeal diseases who were admitted to the Department of Otolaryngology, the First Affiliated Hospital of Kunming Medical University from May 2020 to December 2021 were retrospectively analyzed. The RSI and RFS scores, the Formwitz score of pepsin immunohistochemistry, and the results of pepsin detection kit were recorded. ICC group correlation coefficient and Kappa consistency analysis was used for three detection methods. Results:Among 61 patients, 30 cases were positive and 31 cases were negative for the pepsin test kit, with a positive rate of 49.18%. The positive rate of pepsin immunohistochemistry was 45.90%（28/61）, and the diagnostic agreement rate between the two was 70.49%. The consistency between them was high（κ=0.409）. The positive rate of RSI and RFS in diagnosing LPRD was 62.30%（38/61）, and the consistency rate was 73.77% with pepsin detection kit. The consistency between them was high（κ=0.486）. Taking pepsin IHC as the reference standard, the sensitivity, specificity, positive predictive value and negative predictive value of pepsin detection kit were 71.43%（20/28）, 69.70%（23/33）, 66.67%（20/30） and 74.19%（23/31）, respectively. Using RSI and RFS scales as reference criteria, the sensitivity, specificity, positive predictive value and negative predictive value of pepsin detection kit were 89.29%（25/28）, 60.61%（20/33）, 65.79%（25/38） and 86.96%（20/23）, respectively. Analysis of correlation coefficient within ICC group: ICC value was 0.628, 95% confidence interval（0.497-0.741）, the three methods have good consistency. Conclusion:The RSI and RFS scale scores were in good agreement with the pepsin test kit, and the pepsin test kit was also in good agreement with pepsin immunohistochemistry. As a non-invasive diagnostic technique, the pepsin test kit can be widely used in the diagnosis of pharyngeal reflux in combination with pepsin immunohistochemistry and RSI and RFS scale.

Involvement of Laryngopharyngeal Reflux in Ocular Diseases: A State-of-the-Art Review.

BACKGROUND: Laryngopharyngeal reflux-associated symptoms embrace a wide variety of head and neck manifestations. Its participation in eye disorders has recently been postulated, and there is currently no consensus in this regard. The aim of this manuscript is to review the role of reflux in the development of ocular signs and symptoms, and its physio-pathological mechanisms. METHODS: A systematic approach based on the preferred reporting Items for a systematic review and meta-analysis checklist with a modified population, intervention, comparison, and outcome framework was used to structure the review process of studies that evaluated the possible association, with clear diagnostic methods, of laryngopharyngeal reflux and ocular signs and symptoms. Search was conducted in different indexed databases (PubMed/MEDLINE, the Cochrane Library, Scielo and Web of Science) and through the meta-searcher Trip Database with the keywords: reflux, laryngitis, laryngopharyngeal, gastroesophageal, ocular, eye, symptoms, signs, conjunctivitis, keratitis, dacryocystitis, dry eye. RESULTS: Seven studies met the inclusion criteria, in which the primary acquired nasolacrimal duct obstruction and the ocular surface disease were evaluated. The local increase of eye pepsin concentration (>2.5 ng/mL) may affect ocular surface though its direct proteolytic activity and the local expression of proinflammatory cytokines. The H. Pylori, with a similar mechanism to reach the lacrimonasal duct, would be associated with the release of proinflammatory and vasoactive substances that would lead to a mucosa injury and chronic inflammation. Ocular Surface Disease Index seems to correlate directly with the reflux severity, with cut-off of 41.67 score as predictor for disease. DISCUSSION: The role of laryngopharyngeal reflux in the development of ocular disorders has not yet been demonstrated and data are limited and heterogeneous. It seems theoretically conceivable that pepsin may reach lachrymal duct area through hypopharyngeal-nasal gaseous reflux events. Future studies using objective testing for diagnosis and pepsin detection into the tear and nasal mucosa are needed in order to explore this potential relationship.

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.

Diagnostic thresholds and optimal collection protocol of salivary pepsin for gastroesophageal reflux disease.

Gastroesophageal reflux disease (GERD) is primarily diagnosed based on symptoms and response to a proton-pump inhibitor (PPI) trial. Gold standard testing requires an invasive endoscopic procedure, often with ambulatory pH monitoring. Salivary pepsin is a potential noninvasive modality for GERD diagnosis. This study aimed to assess diagnostic performance of salivary pepsin thresholds for GERD and determine optimal collection protocol of saliva in an external validation cohort. Over 10 months, adults with symptoms of GERD undergoing esophagogastroduodenoscopy with wireless pH-monitoring off PPI were enrolled. Saliva was self-collected by participants over 4 days across three different time points: fasting ante meridiem (AM), post-prandial, and bedtime (PM). Pepsin levels were calculated via Peptest. Pepsin variability and agreement were determined using linear mixed effects models and intraclass correlation. Validation of diagnostic threshold and performance characteristics were evaluated by receiver-operator curve analysis. Twenty participants enrolled in the study; 50% with physiologic acid exposure (acid exposure time < 4% no GERD) and 50% with elevated acid exposure (GERD). Mean pepsin concentrations were significantly lower in the AM (22.6 ± 25.2 ng/mL) compared to post-prandial (44.5 ± 36.7 ng/mL) and PM (55.4 ± 47.0 ng/mL). Agreement between pepsin concentrations across 3 days was substantial for AM samples (kappa 0.61), with lower agreement for post-prandial and PM samples. A single AM pepsin concentration of 25 ng/mL was 67% accurate for GERD with 56% sensitivity and 78% specificity. This validation study highlights fair accuracy and performance characteristics of a single fasting AM salivary pepsin concentration for the diagnosis of GERD.

Optimal Timing of the Salivary Pepsin Test for the Diagnosis of Laryngopharyngeal Reflux.

OBJECTIVE: To investigate the optimal time point for diagnosing laryngopharyngeal reflux (LPR) through combining 24-h hypopharyngeal-esophageal multichannel intraluminal impedance-pH (24-h HEMII-pH) monitoring and the multi-time point salivary pepsin test (MTPSPT). STUDY DESIGN: Prospective uncontrolled trial. METHOD: Patients with and without LPR symptoms were included as the test group and the control group, respectively. The patients in the test group underwent 24-h HEMII-pH and MTPSPT. The results of 24-h HEMII-pH were used as a diagnostic criterion for LPR, and the diagnostic value of salivary pepsin tests performed at different time points was compared by receiver operating characteristic (ROC) analysis. RESULTS: A total of 153 patients were included. Based on 24-h HEMII-pH, the positive rate of LPR in the test group of patients was 84.00%. In the control group, only one person (3.57%) had a positive salivary pepsin test result. The area under the curve (AUC) of the MTPSPT was 0.827. In addition, we separately calculated the AUC of the combined salivary pepsin test at different time points, and found good diagnostic value (AUC = 0.799) when the test was combined with the waking, 1 and 2 h after breakfast and lunch, and 1 h after dinner tests. However, when the number of tests were further increased, the diagnostic value did not improve significantly. CONCLUSION: Salivary pepsin testing combined with waking, 1 h and 2 h after breakfast and lunch, and 1 h after dinner has almost the same diagnostic value as MTPSPT, and testing at these time points can be an effective method for diagnosing LPR. LEVEL OF EVIDENCE: 3 Laryngoscope, 133:1706-1711, 2023.

Diagnostic utility of salivary pepsin in laryngopharyngeal reflux: a systematic review and meta-analysis.

OBJECTIVES: Salivary pepsin has emerged as a biomarker for Laryngopharyngeal Reflux (LPR), which, however, has been questioned for its efficacy due to a lack of supporting medical data. Therefore, this study analyzed the diagnostic value of salivary pepsin for LPR and assessed a better cutoff value. METHODS: Studies were searched in PubMed, Embase, and Cochrane Library from their receptions to October 1, 2021. Then, RevMan 5.3 and Stata 14.0 were utilized to summarize the diagnostic indexes for further meta-analysis. Data were separately extracted by two reviewers according to the trial data extraction form of the Cochrane Handbook. The risk of bias in Randomized Control Trials (RCTs) was evaluated with the Cochrane Risk of Bias Tool. RESULTS: A total of 16 studies matched the criteria and were subjected to meta-analysis. The results revealed a pooled sensitivity of 61% (95% CI 50%-71%), a pooled specificity of 67% (95% CI 48%-81%), a positive likelihood ratio of 2 (95% CI 1.2-2.8), a negative likelihood ratio of 0.58 (95% CI 0.47‒0.72), and the area under the receiver operating characteristic curve of 0.67 (95% CI 0.63‒0.71). Subgroup analyses indicated that the cutoff value of pepsin at 50 ng/mL had a higher degree of diagnostic accuracy than that of pepsin at 16 ng/mL in cohort studies. CONCLUSION: The review demonstrated low diagnostic performance of salivary pepsin for LPR and that the cutoff value of 50 ng/mL pepsin had superior diagnostic accuracy. Nevertheless, the diagnostic value may vary dependent on the utilized diagnostic criteria. Therefore, additional research is needed on the improved way of identifying salivary pepsin in the diagnosis of LPR, and also longer-term and more rigorous RCTs are warranted to further assess the effectiveness of salivary pepsin.

Effects of three endotracheal tube cuff pressure control measures on microaspiration of gastric content: Study protocol for randomised controlled trial.

AIM: To analyse the effect of endotracheal tube cuff pressure control measures on the microaspiration of the stomach contents by measuring at the level of pepsin in deep tracheal aspiration. DESIGN: A single-blind, randomised controlled trial. METHODS: This trial protocol was reported using the SPIRIT checklist. Endotracheal tube cuff pressure control will be provided with pilot balloon finger palpation, intermittent and continuous. The pepsin level will be measured during deep tracheal secretions in order to assess the effect of different endotracheal tube cuff pressure control measures on the microaspiration of the stomach contents. The samples will be examined within the first 4 h, between the 5th and 24th hours, and between the 25th and 48th hours after intubation. The level of pepsin will be considered positive according to the cut-off value. In addition, the effect of different endotracheal tube cuff pressure controls on the incidence of ventilator-associated pneumonia will be examined. In study group 1, study group 2 and the control group, the number of patients is planned to be 56. TRIAL REGISTRATION: ClinicalTrials.gov Identifier, Number NCT04061083. Registered in 2019. DISCUSSION: The findings will show the effect of different endotracheal tube cuff pressure control methods on microaspiration of stomach content and the possible changes in pepsin level in deep tracheal aspirates. CONCLUSION: This study will shed light on future studies regarding pepsin level as a biomarker in treatment and follow-up patients receiving mechanical ventilator support using an ETT and emphasise the importance of multidisciplinary studies. RELEVANCE TO CLINICAL PRACTICE: As a result of the findings to be obtained from this study, the effect of endotracheal tube cuff pressure control on gastric content microaspiration and ventilator-associated pneumonia will be determined and the most appropriate endotracheal tube cuff pressure control method will be identified to prevent it. Nurses' awareness of endotracheal tube cuff pressure measurement methods will be increased. The frequency and methods of endotracheal tube cuff pressure control will provide strong evidence that can be included in the ventilator-associated pneumonia prevention care bundle.

Relationship Between Intra-Abdominal pressure and microaspiration of gastric contents in critically ill mechanically ventilated patients.

The relationship between increased intra-abdominal pressure (IAP) and microaspiration of oro-gastric content in mechanically-ventilated patients has not yet been established. Microaspiration is proposed as one of the causes of ventilator-associated pneumonia (VAP). We aimed to investigate whether mechanically-ventilated patients with increased IAP present evidence of lung microaspiration by assessing pepsin levels in bronchial secretions and evaluated the relationship between pepsin and VAP. 68 mechanically-ventilated patients and 10 control subjects were recruited from an academic ICU in Greece. IAP, pH, pepsin and total protein levels, in bronchial secretions, were assessed within 14 days. Patients underwent assessment for timely VAP diagnosis based on clinical, radiological and laboratory criteria. Pepsin and total protein levels were significantly elevated in patients compared to controls. Pepsin values correlated significantly with IAP (r = 0.61, ***p < 0.001). Multivariate regression analysis showed that IAP was an independent risk factor for increased pepsin values in bronchial secretions [OR95%CI 1.463(1.061-1.620), *p = 0.014]. Pepsin values were higher in patients with VAP, while IAP was independently associated with VAP. There was an indication towards increased VAP in patients with increased pepsin. In conclusion, our results show that pepsin in bronchial secretions may be elevated when IAP is increased, indicating microaspiration and potentially VAP.

Association of enteral feeding with microaspiration in critically ill adults.

AIM: This study explored relationships between enteral feeding and tracheal pepsin A. BACKGROUND: Mechanically ventilated (MV) patients receiving enteral feeding are at risk for microaspiration. Tracheal pepsin A, an enzyme specific to gastric cells, was a proxy for microaspiration of gastric secretions. METHODS: Secondary analysis of RCT data from critically ill, MV adults was conducted. Microaspiration prevention included elevated head of bed, endotracheal tube cuff pressure management, and regular oral care. Tracheal secretions for pepsin A were collected every 12 h. Microaspiration was defined as pepsin A ≥ 6.25 ng/mL. Positive pepsin A in >30 % of individual tracheal samples was defined as abundant microaspiration (frequent aspirator). Chi-squared, Fisher's Exact test, and generalized linear model (GLM) were used. RESULTS: Tracheal pepsin A was present in 111/283 (39 %) mechanically ventilated patients and 48 (17 %) had abundant microaspiration. Enteral feeding was associated with tracheal pepsin A, which occurred within 24 h of enteral feeding. Of the patients who aspirated, the majority received some enteral feeding 96/111 (86 %), compared to only 15/111 (14 %) who received no feeding. A greater number of positive pepsin A events occurred with post-pyloric feeding tube location (55.6 %) vs. gastric (48.6 %), although significant only at the event-level. Frequent aspirators (abundant pepsin A) had higher pepsin A levels compared to infrequent aspirators. CONCLUSIONS: Our findings confirmed the stomach as the microaspiration source. Contrary to other studies, distal feeding tube location did not mitigate microaspiration. Timing for first positive pepsin A should be studied for possible association with enteral feeding intolerance.

[Expression of pepsin in nasopharyngeal carcinoma and its correlation with quality of life after radiotherapy].

Objective: By analyzing the expression of pepsin in nasopharyngeal carcinoma (NPC) tissues, to investigate the correlation between laryngeal reflux (LPR) and NPC, as well as the effect of LPR on the quality of life of patients with NPC after radiotherapy. Methods: A total of 133 patients with NPC who underwent radiotherapy at the Department of Otorhinolaryngology of the Affiliated Hospital of Guizhou Medical University and the Affiliated Cancer Hospital of Guizhou Medical University from 2005 to 2019 were enrolled consecutively, including 90 males and 43 females, aged (44.32±7.47) years old. At the same period, 58 patients with chronic nasopharyngitis who underwent nasopharyngeal biopsy were selected as the control group. Immunohistochemical method was used to detect the expression of pepsin in nasopharyngeal specimens of the two groups. In addition, 188 normal individuals were selected as the normal group in the same period. NPC patients before and within 6 months after radiotherapy were inverstigated by the General Information Questionnaire and the Quality of Life Scale, and the pepsin levels in saliva of NPC patients before and after radiotherapy and the individuals in normal group were measured. SPSS 21.0 software was used for statistical analysis. Results: Pepsin expression in 133 specimens of NPC patients was strongly positive in 24 cases (18.05%), positive in 21 cases (15.79%), weakly positive in 69 cases (51.88%), and negative in 19 cases (14.29%). The specimens of control group had 10 cases of weakly positive (17.24%), 48 cases of negative (82.76%), but no strong positive or positive pepsin expression. The rate of positive pepsin expression in the NPC group was higher than that in the control group, with a statistically significant (χ2=83.15, P<0.001). The pepsin content in the saliva of NPC patients after radiotherapy ((30.31±7.82) ng/ml) was higher than that before radiotherapy ((20.47±8.21) ng/ml) and the normal group (5.11±2.13) ng/ml), and the pepsin content in saliva before radiotherapy was higher than that in the normal group, and all differences were statistically significant (all P<0.05). After radiotherapy, the five functional domains of quality of life and overall quality of life of NPC patients decreased, while the related symptom scores increased (all P<0.05). Multiple linear regression analysis showed that pepsin content in saliva was the influential factor of five functional domains of quality of life, related symptoms and overall quality of life in NPC patients after radiotherapy (all P<0.05). Conclusion: The positive rate of pepsin expression in NPC tissues is high, and the pepsin in saliva before and after radiotherapy of NPC patients is significantly higher than that in normal, suggesting that LPR may be involved in the process of NPC and affect the quality of life after radiotherapy in NPC patients.

Obstructive sleep apnoea patients vs laryngopharyngeal reflux disease: Non-invasive evaluation with NBI and pepsin detection in tears.

Obstructive sleep apnoea (OSA) and laryngopharyngeal reflux disease (LPR) are two common diseases that lower patients' quality of life. OSA is defined by cyclic events of airflow obstruction that occur during sleep, while LPR is characterized by upper airway inflammatory signs and symptoms due to the return of gastroduodenal gaseous and liquid elements. pH-metry is the gold standard in LPR diagnosis, but considering its invasiveness among other negative traits, questionnaires that catalog symptoms and signs of the disease such as Reflux Symptoms Index (RSI) and Reflux Finding Score (RFS) are preferred. Moreover, LPR can be evaluated by testing the presence of pepsin in tears, and Narrow Band Imaging (NBI) has been introduced for the early diagnosis of larynx oncological disease. This paper aims to test whether LPR is more frequent in OSA patients than in control ones, performing a non-invasive protocol composed of RSI, RFS test (with light vs. NBI techniques), followed by pepsin detection in tears. 68 LPR patients were enrolled in the study (45 with OSA and 23 without OSA). A strong linear relationship between Apnea-Hypopnea Index (AHI) and Oxygen Desaturation Index (ODI) was found, and patients who presented pepsin in tears had higher values of AHI and ODI in comparison to patients without it. Pathological RFS and NBI showed higher values of AHI and ODI in comparison to the control group. Furthermore, pathological RSI showed higher values of AHI and ODI in comparison to the control group. In conclusion, this diagnostic combined non-invasive protocol may be a good method to perform an early diagnosis of LPR.

The role of Glut-1 and H+/K+-ATPase expression in hyperplasia of mice laryngeal epithelium induced by pepsin.

PURPOSE: To explore the role played by Glut-1 and H+/K+-ATPase in pepsin-induced, mouse laryngeal epithelial proliferation, growth, and development. METHODS: We established a mouse model of laryngopharyngeal reflux and measured Glut-1 and H+/K+-ATPase expression levels in mouse laryngeal epithelium treated with artificial gastric juice containing pepsin. RESULTS: Artificial pepsin-containing gastric juice induced significant hyperplastic changes in mouse laryngeal epithelium compared to control mice at 15, 30, and 45 days. Inhibition of Glut-1 expression by 2-DG significantly suppressed such hyperplasia compared to mice exposed to artificial gastric juice containing pepsin at 15, 30, and 45 days. After treatment with pepsin-containing artificial gastric juice, RT-PCR and Western blotting showed that the levels of Glut-1 and H+/K+-ATPase α, ß increased significantly. CONCLUSIONS: Pepsin-containing artificial gastric juice promoted mouse laryngeal epithelial hyperplasia associated with abnormal expression of Glut-1 and H+/K+-ATPase α, ß.

Role and mechanism of Glut-1 and H+/K+-ATPase expression in pepsin-induced development of vocal cord leukoplakia.

PURPOSE: We investigated the role of Glut-1 and H+/K+-ATPase expression in pepsin-induced development of human vocal cord leukoplakia cells (HVCLCs). Next, we analyzed the relationship between Glut-1 and H+/K+-ATPase expression with the clinicopathological features of laryngeal carcinoma. METHODS: Glut-1 and H+/K+-ATPase expression levels in HVCLCs were determined after treatment with artificial gastric juice containing pepsin and laryngeal carcinoma tissues. RESULTS: Exposure to pepsin-containing artificial gastric juice significantly enhanced the migration and proliferation of VSCLCs in a time-dependent manner. The apoptotic rate of VSCLCs decreased over time after exposure to pepsin and reached a nadir on day 7 (p < 0.01). With increasing duration of exposure to pepsin, the proportion of VSCLCs in G0/G1 phase decreased and the proportions in the S and G2/M phases significantly increased (p < 0.05). After treatment with pepsin-containing artificial gastric juice, RT-PCR and Western blotting showed that the expression of Glut-1 and H+/K+-ATPase α, ß significantly increased in HVCLCs compared to in the absence of pepsin (p < 0.05). The expression of Glut-1 and H+/K+-ATPase α, ß gradually increased from vocal cord leukoplakia (VLC) to laryngeal carcinoma (p < 0.05). Lentivirus-mediated inhibition of Glut-1 expression in VCL significantly inhibited the cells' migration and proliferation (p < 0.05) but enhanced their apoptosis (p < 0.05). Also, inhibition of Glut-1 expression resulted in an increased proportion of cells in G0/G1 phase and a significantly decreased proportion in G2/M phase (p < 0.05). CONCLUSIONS: Elevated Glut-1 expression may promote the development of VCL by upregulating laryngeal H+/K+-ATPase expression to reactivate absorbed pepsin, thus damaging the laryngeal mucosa.

Carangoides bartholomaei (Cuvier, 1833) stomach: a source of aspartic proteases for industrial and biotechnological applications / Estômago de Carangoides bartholomaei (Cuvier, 1833): uma fonte de proteases aspárticas para aplicações industriais e biotecnológicas

The viscera and other residues from fish processing are commonly discarded by the fishing industry. These by products can be a source of digestive enzymes with industrial and biotechnological potential. In this study, we aimed at the extraction, characterization, and application of acidic proteases from the stomach of Carangoides bartholomaei (Cuvier, 1833). A crude extract from the stomachs was obtained and submitted to a partial purification process by salting-out, which obtained a Purified Extract (PE) with a specific proteolytic activity of 54.0 U·mg-¹. A purification of 1.9 fold and a yield of 41% were obtained. The PE presents two isoforms of acidic proteases and a maximum proteolytic activity at 45 °C and pH 2.0. The PE acidic proteolytic activity was stable in the pH range of 1.5 to 7.0 and temperature from 25 °C to 50 °C. Purified Extract kept 35% of its proteolytic activity at the presence of NaCl 15% (m/v) but was totally inhibited by pepstatin A. Purified Extract aspartic proteases presented high activity in the presence of heavy metals such as Cd2+, Hg2+, Pb2+, Al3+, and Cu2+. The utilization of PE as an enzymatic addictive in the collagen extraction from Nile tilapia scales has doubled the process yield. The results indicate the potential of these aspartic proteases for industrial and biotechnological applications.

As vísceras e outros resíduos do processamento de peixes são geralmente descartados pela indústria pesqueira. Esses resíduos podem ser uma fonte de enzimas digestivas com potencial industrial e biotecnológico. Neste estudo, objetivamos a extração, caracterização e aplicação de proteases aspárticas do estômago de Carangoides bartholomaei (Cuvier, 1833). Um extrato bruto do estômago foi obtido e submetido a um processo de purificação parcial, que obteve um Extrato Purificado (EP) com uma atividade proteolítica específica de 54,0 U·mg-¹. Foi obtida uma purificação de 1,9 vezes e um rendimento de 41%. O EP apresenta duas isoformas de proteases ácidas e atividade proteolítica máxima a 45 °C e pH 2,0. A atividade proteolítica do EP foi estável na faixa de pH de 1,5 a 7,0 e temperatura de 25 °C a 50 °C. O EP manteve 35% de sua atividade proteolítica na presença de NaCl a 15% (m/v), mas foi totalmente inibida pela pepstatina A. As proteases ácidas do EP apresentaram alta atividade na presença de metais pesados como o Cd2+, Hg2+, Pb2+, Al3+ e Cu2+. A utilização de EP como aditivo enzimático na extração de colágeno a partir de escamas de tilápia do Nilo dobrou o rendimento do processo. Os resultados indicam um potencial dessas proteases para aplicações industriais e biotecnológicas.