Pepsin Concentration Research Articles

Probing structural modification of milk proteins in the presence of pepsin and/or acid using small- and ultra-small-angle neutron scattering

Acid- and pepsin-induced milk protein coagulation plays a crucial role in the gastric digestion of milk. Real-time structural evolution at a nano- (e.g. colloidal calcium phosphate (CCP) and micelle) and micro- (gel network) level of unheated and heated (85 °C for 30 min) bovine milk was examined under acidic conditions and at low and high concentrations of pepsin using ultra-small- and small-angle neutron scattering (USANS and SANS), small-amplitude oscillatory rheometry and confocal scanning laser microscopy. Milk was treated with glucono-δ-lactone (GDL), pepsin or a combination of GDL and pepsin to induce coagulation. Heat-treated milk showed a faster increase in elastic storage modulus (G′) and scattering intensity (USANS and SANS) compared with unheated milk when coagulated with GDL or the combination of GDL and pepsin. At pH 6.3, heat treatment retarded pepsin (1.10 U/mL)-induced milk coagulation, with slower increases in G′ and scattering intensity. At a high concentration of pepsin (2000 U/mL) that mimics the concentration found in the stomach, general proteolysis followed coagulation. Heat treatment retarded coagulation but accelerated curd proteolysis. This study demonstrates how time-resolved USANS and SANS can be used to investigate the structural evolution of protein coagulation and degradation under gastric environment conditions at nano- and micro-metre length scales.

The association between salivary pepsin and gastroesophageal reflux disease: A meta-analysis.

The definitive diagnosis of gastroesophageal reflux disease (GERD) often requires invasive investigations like upper gastrointestinal endoscopy or reflux monitoring. We aimed to explore the relationship between salivary pepsin and GERD and its value as a non-invasive diagnostic tool. Databases (PubMed, Web of Science, Cochran Library, and EMBASE) were searched from their inception to January 22, 2024 to explore the correlation of salivary pepsin with GERD. The meta-analysis data retrieved were summarized, including the salivary pepsin concentration, sensitivity of diagnosis (SEN), specificity of diagnosis (SPE), negative likelihood ratio, positive likelihood ratio, diagnostic odds ratio, and receiver operating characteristic (ROC) curve. The meta-analysis comparing salivary pepsin concentration in two groups (proven GERD and non-GERD) with 18 studies revealed that the proven GERD group had higher salivary pepsin concentration than the non-GERD group (SMD = 1.74 [95% CI 1.14-2.34]). The meta-analysis of salivary pepsin diagnostic value for proven GERD incorporated 23 studies. The results showed pooled SEN (0.73 [95% CI 0.66-0.80]), SPE (0.72 [95% CI 0.65-0.78]), positive likelihood ratio (2.61 [95% CI 2.02-3.39]), negative likelihood ratio (0.37 [95% CI 0.28-0.50]), diagnostic odds ratio (7.03 [95% CI 4.24-11.66]) and area under the SROC curve (0.79 [95% CI 0.75-0.82]). GERD patients presented a higher salivary pepsin concentration. Salivary pepsin is both sensitive and specific in identifying GERD, making it a promising non-invasive marker for diagnosis.

586. VALUE OF PEPSIN IN SALIVA TO ASSESS THE POSTOPERATIVE OUTCOME OF PATIENTS WITH GERD

Abstract Background The aim of this study was to evaluate the value of salivary pepsin to assess the outcome of surgical treatment of patients with gastroesophageal reflux (GERD). Methods Forty-five consecutive patients with GERD despite proton pump inhibitor treatment received laparoscopic anti-reflux surgery (LARS). 24-hour esophageal pH-monitoring (MII-pH) and esophageal manometry (HRM) data were documented preoperatively and at 3-month follow-up. Clinical symptoms were rated with the Gastrointestinal Quality of Life Index (GIQLI) and gastrointestinal symptoms were evaluated by a standardized symptom checklist (SCL), assessing the severity and intensitiy of 14 different symptoms. Simultaneous to MII-pH the collection of 3 saliva samples per patient was performed. Treatment failure was defined as improvement of GIQLI and SCL of < 10 points, despite showing a normal DeMeester score. Results At baseline, all patients showed a pathological MII-pH measurement. Furthermore, all patients showed postoperatively a normal DeMeester score (mean 7.10 ± 4.56). Ten patients were defined as treatment failures with a change of pepsin concentration from a mean value of 198.73 ng/mL to 186.00 ng/mL (p>0.05). In patients defined as treatment success, mean pepsin value decreased from 205.83 ng/mL to 85.24 ng/mL (p<0.001). Conclusion Salivary pepsin could be a marker for treatment success after LARS. However, larger studies are required to reach firm conclusions.

Does Extraesophageal Reflux Support the Development of Lung Adenocarcinoma? Analysis of Pepsin in Bronchoalveolar Lavage in Non-Smoker Patients.

The significance of extraesophageal reflux as a risk factor in lung adenocarcinoma has been understudied. In this study, we investigated whether extraesophageal reflux leads to higher pepsin concentrations in bronchoalveolar lavage (BAL) in patients with lung adenocarcinoma compared to controls. Subjects were recruited from non-smoker patients (lifelong non-smokers and ex-smokers with more than 5 years of non-smoking history) who had undergone bronchoscopy due to pulmonary abnormalities on a CT scan and met the inclusion criteria. Based on histological verification of the lung process, the patients were divided into three groups: (1) lung adenocarcinoma, (2) pulmonary metastases, and (3) lung sarcoidosis. Lung adenocarcinoma cases were further categorized as central or peripheral. BAL samples collected during bronchoscopy were quantitatively analyzed by enzyme-linked immunosorbent assay (ELISA) to measure pepsin levels. No statistically significant difference in pepsin concentration was observed between the lung adenocarcinoma group and control groups (p = 0.135). After excluding hemorrhagic BAL samples, the pepsin concentration was significantly the lowest in patients with lung adenocarcinoma (p = 0.023) compared to the control groups. The results of the study do not support the hypothesis of a higher occurrence of extraesophageal reflux (evaluated as the amount of pepsin in BAL) in non-smoker patients with lung adenocarcinoma.

Diagnostic value of the pepsin concentration in saliva and induced sputum for gastroesophageal reflux-induced chronic cough: a prospective clinical study.

Finding a simple, effective and rapid diagnostic method to improve the diagnosis of gastroesophageal reflux-induced chronic cough (GERC) is indicated. Our objective was to determine the diagnostic value of the pepsin concentration in saliva and induced sputum for GERC. 171 patients with chronic cough were enrolled. The diagnosis and treatment followed the chronic cough diagnosis and treatment protocol. Saliva and induced sputum were collected, and the pepsin concentration was determined using Peptest. A Gastroesophageal Reflux Diagnostic Questionnaire (GerdQ) was completed. The diagnostic value of the pepsin concentration in saliva and induced sputum for GERC was analysed and compared. The salivary pepsin concentration predicted GERC with an area under the receiver operating characteristic curve (AUC) of 0.845. The optimal cut-off value was 76.10 ng·mL-1, the sensitivity was 83.58% and the specificity was 82.69%. The pepsin concentration in the induced sputum supernatant for GERC had an AUC of 0.523. When GerdQ was used for GERC diagnosis, the AUC was 0.670 and the diagnostic value of salivary pepsin was better compared to GerdQ (DeLong test, p=0.0008). Salivary pepsin had a comparable diagnostic value to GerdQ (AUC 0.779 versus 0.826; p=0.4199) in acidic GERC. Salivary pepsin had superior diagnostic value compared to GerdQ (AUC 0.830 versus 0.533; p<0.0001) in non-acidic GERC. A salivary pepsin concentration >76.10 ng·mL-1 is of good diagnostic value for GERC, especially in non-acidic GERC. The pepsin concentration in induced sputum has a low diagnostic value.

Study of Factors Influencing the Oral Bioaccessibility of Commonly Used and Detected Pesticides in Bananas and Mangoes Based on in vitro Methods.

Estimating the impact of pesticide residue bioaccessibility in fruits on dietary exposure is a complex task in human health risk assessment. This research investigated the bioaccessibility of ten commonly used and detected pesticides in bananas and mangoes, as well as the factors influencing it, using an in vitro model. The highest bioaccessibility was observed at pH levels of 2.5 and 6.5 in the gastric and intestinal stages, respectively. Bioaccessibility decreased significantly with increasing solid/liquid ratios for most pesticides. The consumption of protein and four dietary components (carbohydrates, protein, lipids, and dietary fiber) could significantly reduce pesticide bioaccessibility by 9.89-48.32% (p < 0.05). Bioaccessibility in oral and gastric stages among four populations followed the order of adults/the elderly > children > infants, due to decreasing concentrations of α-amylase and pepsin. Pesticides in bananas generally exhibited a higher bioaccessibility (18.65-82.97%) compared to that in mangoes (11.68-87.57%). Bioaccessibility showed a negative correlation with the Log P values of the target pesticide, while no clear relationship was found between bioaccessibility and initial pesticide concentrations. Incorporating bioaccessible pesticide concentrations into risk assessments could lower dietary risk estimates by 11.85-79.57%. Assessing human exposure to pesticides based on bioaccessibility would greatly improve the accuracy of the risk assessment.

Fully Organic Sensors for Continuous Real-Time Digestion Monitoring.

Monitoring the gastric digestive function is important for the diagnosis of gastric disorders and drug development. However, there is no report on the in situ and real-time monitoring of digestive functions. Herein, we report a flexible fully organic sensor to effectively monitor protein digestion in situ in a simulated gastric environment for the first time. The sensors are made of a blend of gluten that is a protein and poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) that is a conducting polymer. During the protein digestion, the breakdown of the polypeptides increases the level of separation among the PEDOT chains, thereby increasing the resistance. The resistance variation is sensitive to various conditions, including the concentration of pepsin that is the enzyme for protein digestion, temperature, pH value, and digestive drugs. Hence, these sensors can provide real-time information about the digestion and efficacy of digestive drugs. In addition, the signals can be collected via a convenient wireless communication manner.

BIOCHEMICAL INDICATORS OF GASTRIC JUICE IN INCOMPETENCE OF THE PHYSIOLOGICAL GASTRIC CARDIA

Aim. This study aimed to evaluate the biochemical characteristics of gastric juice in cases incompetence of the physiological cardia (IPC) at the gastroesophageal junction. Methods. Gastric juice samples were collected from 42 patients diagnosed with hiatal hernia (HH) at the State Institution "Institute of Gastroenterology of the National Academy of Medical Sciences of Ukraine". Patients were classified into type I (sliding) HH (n=26) and type II (paraesophageal) HH (n=16), with a control group of healthy volunteers (n=9). Results. Analysis included pH, pepsin concentration, bile acids, total calcium and stable metabolites of nitric oxide (NOx). In type I HH, gastric juice showed increased pH (3.73±0.49) and elevated pepsin concentration (1.33±0.22 mg/ml) compared to controls (p&lt;0.01 and P&lt;0.05 respectively), indicating hypoacidity and hyperfunction of chief cells. Type II HH exhibited pH levels (2.34±0.72) similar to controls and no significant difference in pepsin concentration. NOx levels in type I HH were lower (P&lt;0.05) compared to controls, suggesting reduced NOergic system activity. Calcium concentration in gastric juice did not significantly differ between groups. Conclusions. These findings suggest that type I HH is associated with disturbances in gastric secretion regulation, possibly unrelated to duodenogastric reflux. Further investigation is warranted to elucidate the underlying pathophysiological mechanisms.

Elevated Saliva Pepsin Concentration as a Risk Factor for Asthma in Children with Allergic Rhinitis: A Preliminary Study.

This study aimed to explore whether saliva pepsin concentration (SPC) could be regarded as a risk factor for the occurrence and unfavorable control of asthma in children with allergic rhinitis. A prospective study was conducted on a group of 20 consecutive children newly diagnosed with allergic rhinitis and asthma (referred to as the asthma group). All these children underwent fractional exhaled nitric oxide (FeNO) measurement, lung function tests, and assessment of asthma control using the 7-item Childhood Asthma Control Test (C-ACT) score. Simultaneously, a control group consisting of 20 children with simple allergic rhinitis, matched for baseline characteristics, was included. SPC measurement was performed in the two groups. The SPC value was significantly higher in the asthma group than that in the control group (165.0 ± 82.8 ng/mL vs 68.4 ± 34.5 ng/mL) (P < 0.001). In the asthma group, SPC was independently associated with FeNO, the ratio of forced expiratory volume in 1 second (FEV1) to forced vital capacity (FVC), and forced expiratory flow at 50% and 75% of FVC (FEF50 and FEF75) (all P < 0.05). The severity of nasal symptoms evaluated by the visual analogue scale (N-VAS) was independently associated with FEF75, the maximal mid-expiratory flow (MMEF), and C-ACT score (P < 0.05). Direct pepsin exposure and uncontrolled nasal symptoms may play crucial roles in the pathogenesis and progression of childhood allergic asthma. The SPC value can be considered as a risk factor for asthma in children with allergic rhinitis.

Tonghua Liyan granules in the treatment of Laryngopharyngeal reflux disease with stagnation of phlegm and qi syndrome: a randomized, double-blind, placebo-controlled study.

Background: Laryngopharyngeal reflux disease (LPRD) is an extraesophageal syndromic manifestation of gastroesophageal reflux disease (GERD). Despite the increasing incidence of and concern about LPRD, treatment with proton pump inhibitors (PPIs) is unsatisfactory. Here, LPRD was treated with Tonghua Liyan (THLY) granules in combination with PPIs to evaluate treatment efficacy and possible adverse reactions. Methods: Seventy-six LPRD patients with stagnation of phlegm and qi syndrome (SPQS) were randomly divided into an experimental group and a control group. The experimental group received THLY granules combined with rabeprazole capsules. The control group received THLY granule placebo combined with rabeprazole capsules. A parallel, randomized, double-blind, placebo-controlled clinical trial was conducted with these two groups. The treatment cycle was 8weeks. The reflux symptom index (RSI), clinical symptom score, salivary pepsin content, reflux finding score (RFS) and gastroesophageal reflux disease questionnaire (GerdQ) were used to evaluate clinical efficacy. The final efficacy rate was evaluated according to the RSI and clinical symptom score. Results: Compared with those at baseline, all the indicators in the experimental group and control group significantly improved (p < 0.01). In terms of the RSI, clinical symptom score, and RFS, the experimental group had a higher degree of improvement (p < 0.05), and the overall efficacy rate was higher (p < 0.05). In terms of the salivary pepsin concentration and GerdQ, there was no significant difference between the test group and the control group (p > 0.05). Both groups of safety indicators showed no abnormalities and did not cause any allergic reactions in the body. Conclusion: Compared with PPIs alone, THLY granules combined with PPIs are more effective in the treatment of LPRD patients with SPQS in terms of symptoms and signs. This combination treatment, because of its higher clinical efficacy and lack of obvious adverse reactions, is worthy of clinical promotion and further in-depth study. Clinical Trial Registration: www.chictr.org.cn, identifier ChiCTR2100046614.

Determination of pepsin in human saliva using pepsin-susceptible peptide reporter and colorimetric dipstick assay: a prospective, cross-sectional study.

A simple and effective pepsin detection assay is reported based on a pepsin-susceptible peptide (PSP) reporter degradation strategy. PSP, which can be specifically cleaved by pepsin, was modified with fluorescein isothiocyanate (FITC) and biotin at the N- and C-terminals to be used as a reporter for colorimetric detection of dipsticks. A universal lateral flow dipstick consisting of a streptavidin test line for biotin binding and a sample pad immobilized with a gold-labeled polyclonal (rabbit) anti-FITC antibody was used to verify PSP-based pepsin detection. When the PSP reporter reacts with pepsin in a tube, it cleaves into two fragments, and the cleaved fragments do not display any color on the test line. Therefore, the higher the concentration of pepsin is, the greater is the decrease in test line intensity (IT-line) and the higher is the control line intensity (IC-line). First, the PSP cleavage and dipstick assay conditions for pepsin detection was optimized. The ratio of color intensity (IT-line/IC-line) of PSP-based dipstick assay showed a linear relationship with log concentration of pepsin ranging between 4 and 500 ng/mL (R2 = 0.98, n = 6), with a limit of detection of 1.4 ng/mL. It also exhibited high specificity and good reproducibility. Finally, pepsin levels were quantified in saliva samples from healthy controls (n = 34) and patients with laryngopharyngeal reflux (LPR, n = 61). Salivary pepsin levels were higher in patients with LPR than in healthy controls. The salivary pepsin levels correlated with those measured using a conventional enzyme-linked immunosorbent assay kit. Therefore, this PSP-based dipstick assay is a convenient tool for assessing salivary pepsin levels.

Gastric stability of bare and chitosan-fabricated ferritin and its bio-mineral: implication for potential dietary iron supplements.

Iron deficiency anaemia (IDA), the most widespread nutritional disorder, is a persistent global health issue affecting millions, especially in resource-limited geographies. Oral iron supplementation is usually the first choice for exogenous iron administration owing to its convenience, effectiveness and low cost. However, commercially available iron supplementations are often associated with oxidative stress, gastrointestinal side effects, infections and solubility issues. Herein, we aim to address these limitations by employing ferritin proteins-self-assembled nanocaged architectures functioning as a soluble cellular iron repository-as a non-toxic and biocompatible alternative. Our in vitro studies based on PAGE and TEM indicate that bare ferritin proteins are resistant to gastric conditions but their cage integrity is compromised under longer incubation periods and at higher concentrations of pepsin, which is a critical component of gastric juice. To ensure the safe delivery of encapsulated iron cargo, with minimal cage disintegration/degradation and iron leakage along the gastrointestinal tract, we fabricated the surface of ferritin with chitosan. Further, the stoichiometry and absorptivity of iron-chelator complexes at both gastric and circumneutral pH were estimated using Job's plot. Unlike bipyridyl, deferiprone exhibited pH dependency. In vitro kinetics was studied to evaluate iron release from bare and chitosan-fabricated ferritins employing both reductive (in the presence of ascorbate and bipyridyl) and non-reductive (direct chelation by deferiprone) pathways to determine their bio-mineral stabilities. Chitosan-decorated ferritin displayed superior cage integrity and iron retention capability over bare ferritin in simulated gastric fluid. The ability of ferritins to naturally facilitate controlled iron release in conjugation with enteric coating provided by chitosan may mitigate the aforementioned side effects and enhance iron absorption in the intestine. The results of the current study could pave the way for the development of an oral formulation based on ferritin-caged iron bio-mineral that can be a promising alternative for the treatment of IDA, offering better therapeutic outcomes.

Optimization Process of the Pepsin-Solubilized Collagen from Lizardfish (Saurida tumbil Bloch, 1795) Skins by-Product

By-products from the marine fish processing are rich in organic compounds that can be converted into value-added products like collagen, and it is thought as an ideal candidate polymer for such research and medical applications. The lizardfish (Saurida tumbil Bloch, 1795) skin collagen had been investigated by our previous work, but an effective extraction method is needed to increase the yield of collagen. The purpose of this study was to optimize the method used to extract pepsin-solubilized collagen (PSC) from lizardfish skin. We employed an approach of one factor at a time (OFAT), along with response surface methodology (RSM) utilizing a central composite design (CCD), to attain the highest possible yield of the extracted collagen. Additionally, its properties were also assessed comparatively. The suggested optimal conditions for extraction were a pepsin concentration of 1.87%, a liquid-solid ratio of 24.90 mL/g, and a hydrolysis period of 38.09 h. Using these conditions resulted in a PSC yield of 21.82 g/100g, which closely matched the predicted collagen value.

Threshold level of Peptest in diagnosing gastroesophageal reflux disease with extraesophageal symptoms: Evidence from Vietnam.

We aimed to evaluate the application of Peptest, a novel technique to detect pepsin in the saliva, and identify its threshold level for the diagnosis of gastroesophageal reflux disease (GERD) with extraesophageal symptoms. A cross-sectional study was conducted in two groups: patients with extraesophageal GERD symptoms (symptomatic group divided into GERD and non-GERD groups according to 24-h esophageal pH-impedance monitoring [pH-I] results) and healthy controls. For the symptomatic group, endoscopy, pH 24 h, high-resolution manometry (HRM), and salivary Peptest were performed. For the healthy control group, only Peptest was done. The accuracy of Peptest was compared with that of pH-I by the Lyon consensus criteria. Chronic laryngitis was the most frequent extraesophageal symptom. On saliva testing, the GERD group had a higher prevalence of positive samples and pepsin concentration than the control group. Between GERD and non-GERD groups, the optimal threshold level was 31.2 ng/mL, with a sensitivity of 86.7% and specificity of 27.5%. The optimal threshold level was 31.4 ng/mL to differentiate GERD from healthy controls, with a sensitivity of 86.7% and specificity of 66.0%. Age, number of total refluxes, DeMeester score, post-reflux swallow-induced peristaltic wave (PSPW) index, and mean nocturnal baseline impedence (MNBI) were associated with pepsin concentration. Regarding HRM metrics, there was no significant difference of pepsin concentration between low/normal upper esophageal sphincter (UES) resting pressure, low/normal lower esophageal sphincter (LES) resting pressure, low/normal 4-s integrated relaxation pressure (IRP4s), and hypomotility/normal motility. Patients with extraesophageal symptoms had a higher prevalence of positive Peptest. The optimum threshold level of 31.4 ng/mL had high sensitivity and moderate specificity to differentiate between patients with GERD and healthy controls.

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

To study the diagnostic value of salivary pepsin tests for detecting laryngopharyngeal reflux (LPR) in patients with primary burning mouth syndrome (BMS). 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 ≥ 100ng/mL cutoffs. Receiver operating characteristic curve (ROC) was evaluated. 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 ≥ 100ng/mL, respectively. The ROC analysis reported that a threshold of ≥ 21.5ng/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). 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.

Preparation of Enzyme-Soluble Swim Bladder Collagen from Sea Eel (Muraenesox cinereus) and Evaluation Its Wound Healing Capacity.

In the present research, the enzyme-facilitated collagen from sea eel (Muraenesox cinereus) swim bladder was isolated, and the collagen characteristics were analyzed. Then, the collagen sponge was prepared and its potential mechanism in promoting skin wound healing in mice was further investigated. Collagen was obtained from the swim bladder of sea eels employing the pepsin extraction technique. Single-factor experiments served as the basis for the response surface method (RSM) to optimize pepsin concentration, solid-liquid ratio, and hydrolysis period. With a pepsin concentration of 2067 U/g, a solid-liquid ratio of 1:83 g/mL, and a hydrolysis period of 10 h, collagen extraction achieved a yield of 93.76%. The physicochemical analysis revealed that the extracted collagen belonged to type I collagen, and the collagen sponge displayed a fibrous structure under electron microscopy. Furthermore, in comparison to the control group, mice treated with collagen sponge dressing exhibited elevated activities of superoxide dismutase (SOD), catalase (CAT), total antioxidant capacity (T-AOC), and glutathione peroxidase (GSH-Px), and decreased levels of malondialdehyde (MDA), interleukin (IL)-1β, interleukin (IL)-6, and tumor necrosis factor (TNF)-α. The collagen sponge dressing effectively alleviated inflammation in the wound area, facilitating efficient repair and rapid healing of the skin tissue. During the initial phase of wound healing, the group treated with collagen sponge dressing exhibited an enhancement in the expressions of cluster of differentiation (CD)31, epidermal growth factor (EGF), transforming growth factor (TGF)-β1, and type I collagen, leading to an accelerated rate of wound healing. In addition, this collagen sponge dressing could also downregulate the expressions of CD31, EGF, and type I collagen to prevent scar formation in the later stage. Moreover, this collagen treatment minimized oxidative damage and inflammation during skin wound healing and facilitated blood vessel formation in the wound. Consequently, it exhibits significant potential as an ideal material for the development of a skin wound dressing.

Pepsin concentration in oral lavage fluid of rabbit reflux model constructed by dilating the lower esophageal sphincter.

The aim of this study was to explore the changes in pH and pepsin concentrations in oral lavage fluid of rabbit reflux model. A total of 18 New Zealand rabbits were randomly divided into two groups. The lower esophageal sphincters (LESs) of the rabbits in the experimental group (EG) were dilated by balloon after the LESs were localized by manometry. The pH levels of the throat and the lower esophagus were monitored 1 week before and 2 weeks after inflation. Oral lavage fluid was collected 1 week before, and 2 and 8 weeks after inflation. The pH monitoring showed that the percentage of reflux time, the number of reflux events, and the longest time of reflux after the dilation (AE) in the EG were significantly higher than before the dilation (P < 0.01). The pepsin concentrations at 2 and 8 weeks AE in the EG were significantly higher than that before and that in the control group (P < 0.05). Based on receiver operating characteristic curve analysis, the best diagnostic threshold value was 30.3 ng/ml. The reflux model constructed by balloon inflation of the LES in rabbits is characterized by a decrease in throat pH and an increase in salivary pepsin concentration.

Clinical Utility of Pepsin and Bile Acid in Tracheal Secretions for Accurate Diagnosis of Aspiration in ICU Patients.

Aspiration of stomach content or saliva in critical conditions-e.g., shock, intoxication, or resuscitation-can lead to acute lung injury. While various biomarkers in bronchoalveolar lavage fluids have been studied for diagnosing aspiration, none have been conclusively established as early indicators of lung damage. This study aims to evaluate the diagnostic value of pepsin, bile acid, and other biomarkers for detecting aspiration in an intensive care unit (ICU). In this study, 50 ICU patients were enrolled and underwent intubation before admission. The evaluation of aspiration was based on clinical suspicion or documented instances of observed events. Tracheal secretion (TS) samples were collected within 6 h after intubation using sterile suction catheters. Additional parameters, including IL-6, pepsin, and bile acid, were determined for analysis. Pepsin levels were measured with an ELISA kit, while bile acid, uric acid, glucose, IL-6, and pH value in the tracheal secretion were analyzed using standardized lab methods. The 50 patients admitted to the ICU with various diagnoses. The median survival time for the entire cohort was 52 days, and there was no significant difference in survival between patients with aspiration pneumonia (AP) and those with other diagnoses (p = 0.69). Among the AP group, the average survival time was 50.51 days (±8.1 SD; 95% CI 34.63-66.39), while patients with other diagnoses had a mean survival time of 32.86 days (±5.1 SD; 95% CI 22.9-42.81); the survival group comparison did not yield statistically significant results. The presence of pepsin or bile acid in TS patients did not significantly impact survival or the diagnosis of aspiration. The p-values for the correlations between pepsin and bile acid with the aspiration diagnosis were p = 0.53 and p > 0.99, respectively; thus, pepsin and bile acid measurements did not significantly affect survival outcomes or enhance the accuracy of diagnosing aspiration pneumonia. The early and accurate diagnosis of aspiration is crucial for optimal patient care. However, based on this study, pepsin concentration alone may not reliably indicate aspiration, and bile acid levels also show limited association with the diagnosis. Further validation studies are needed to assess the clinical usefulness and reliability of gastric biomarkers in diagnosing aspiration-related conditions. Such future studies would provide valuable insights for improving aspiration diagnosis and enhancing patient care.

Diagnostic Value of Pepsin Measurements in Dysphonia Attributed to Laryngopharyngeal Reflux Disease

To investigate the diagnostic value of pepsin test in detecting laryngopharyngeal reflux (LPR) in patients with suspected LPR-induced dysphonia. Dysphonic and non-dysphonic patients with LPR at the 24-hour hypopharyngeal-esophageal impedance-pH monitoring (HEMII-pH) were recruited from January 2019 to November 2022. Patients collected saliva/sputum samples to measure pepsin concentrations. Symptoms and findings were studied through reflux symptom score (RSS) and reflux sign assessment (RSA). Voice quality was assessed with maximum phonation time, GRBAS, voice handicap index (VHI), and acoustic parameters at baseline and 3-month post-treatment. Sensitivity, specificity, positive (PPV) and negative (NPV) predictive values of pepsin tests for dysphonia-related to LPR were calculated at ≥16ng/mL cutoff. The relationship between HEMII-pH, clinical features, voice quality outcomes, and pepsin measurement was investigated. Sixty-seven patients with LPR at the HEMII-pH completed the evaluations accounting for 30 patients consulting for dysphonia. Dysphonic patients reported higher RSS than non-dysphonic patients. RSS, RSA, laryngeal findings, VHI, and grade of dysphonia significantly improved from baseline to 3-month posttreatment. Pepsin test detected LPR in 73% of dysphonic cases. The pepsin test was 73.3 sensitive and 18.9 specific when considering the highest pepsin level of morning, postlunch, and postdinner sputum collections. Sensitivity, specificity, PPV, and NPV varied regarding the time of sputum collections. There was a strong significant association between the concentration of the morning pepsin test and the severity of laryngeal RSA score (P=0.018). The morning pepsin saliva test concentration was predictive of the 3-month otolaryngological RSS (P=0.014). Pepsin test is a sensitive but poorly specific diagnostic approach for patients with dysphonia attributed to LPR. Multiple pepsin measurements may increase the sensitivity and predictive value of pepsin test. Future large-cohort studies are needed to investigate the accuracy of pepsin test in this population.

Coagulation of model infant formulae: Impact on their in vitro dynamic gastric digestion

The rheological properties and the in vitro dynamic gastric digestion behaviours of model infant formulae containing various ratios of casein to whey protein (0:100, 40:60, 60:40 and 80:20) were investigated using a rheometer and an infant human gastric simulator. The pH profiles and the viscoelastic moduli were determined during acidification by glucono-δ-lactone and at different pepsin concentrations (0, 0.3, 1.0, 1.7 and 2.5 U/mL). The infant formula containing whey protein only formed a weak gel at about pH 5. In the presence of pepsin, all casein-containing infant formulae formed gels at pH ∼6.0 and only low pepsin activity (>0.3 U/mL) was required for the gelation. The strength of the gel/coagulum was dependent mainly on the casein content. Coagulation of protein and flocculation of oil droplets, induced by both pepsin proteolysis and the low pH under gastric conditions, were observed in the infant formulae during dynamic digestion in the human gastric simulator. Confocal images showed that the infant formula containing whey protein only formed smaller flocs of aggregated protein and oil droplets, which may have led to their observed faster protein digestion, than the infant formulae containing a combination of casein and whey protein. The casein-dominant infant formulae had greater aggregation than the whey-protein-dominant infant formulae during gastric digestion, which led to their lower rate of casein digestion. These results suggest that the extent of coagulation and the gastric digestion of the proteins in infant formulae can be controlled by the rational selection of the protein components and the ratio of casein to whey protein, such that different nutritional requirements of infants can be met.