Pepsin Concentration Research Articles

Binding loop of sunflower trypsin inhibitor 1 serves as a design motif for proteolysis-resistant antimicrobial peptides

Although antimicrobial peptides (AMPs) have become powerful drug candidates in the post-antibiotic era, but their low protease stability hinders their clinical application. In the present study, the natural sunflower trypsin inhibitor 1 (SFTI-1) binding loop (CTKSIPPIC) was used to design and synthesize a specific anti-proteolytic sequence template ((RX)n W (RX)n CTKSIPPIC (n = 2, 3; X represents A, I, L, V, F, and W)). After several antibacterial, bactericidal, and toxicity tests, RV3 stood out from the variants and had the highest average selectivity index (SI all = 156.03). It is highly stable in serum, varying pH, temperature, and salt ions as well as under high trypsin, pepsin, or papain concentrations. In a mouse skin inflammation model, established by Pseudomonas aeruginosa infection, RV3 could effectively kill the pathogen, promote wound healing, inhibit inflammatory cell infiltration, and inhibit mRNA and protein expression of TNF-α, IL-6, and IL-1β inflammatory factors. The antibacterial mechanisms of RV3 include combining with lipopolysaccharides and increasing cell membrane permeability, leading to cell membrane rupture and death. These findings indicate that RV3 has great potential for the treatment of bacterial infections.

Analysis of Pepsin Concentration and Influencing Factors in Saliva of Elderly Nasal Feeding Patients

Background Elderly patients receiving nasal feeding have weaker physiological function, and placement of a nasogastric tube weakens the natural barrier of the cardia-esophageal sphincter; therefore, the risk of gastroesophageal reflux (GER) is higher. Many studies have shown that pepsin is extremely sensitive in predicting GERD, so this study intends to investigate the level of pepsin in saliva of elderly patients with nasal feeding and analyze its influencing factors. Methods This was a cross-sectional study. Patients admitted to the Chinese PLA General Hospital from April 2018 to October 2018 who received nasal feeding were included. One ml of saliva was collected from each patient in while sitting during fasting in the morning and 1 hour after lunch for 3 consecutive days. Pepsin was quantified by enzyme-linked immunosorbent assay (ELISA). The patients were predivided into two groups (≥7.75μg/ml or <7.75μg/ml) based on the median pepsin. Baseline and clinical factors were compared. Results The mean age of the patients was 91.09 ± 4.91 years. There were statistical differences in diabetes and feeding methods between the two groups. There was a positive correlation between the morning and postprandial pepsin levels (r = 0.442, P < 0.001), and has no statistical difference (P = 0.175). Multivariate analysis showed that the risk factors for higher pepsin levels were diabetes (odds ratio (OR): 2.67; 95% CI: 1.225-5.819, P = 0.013) and nasal feeding methods (OR: 2.475; 95% CI: 1.183-5.180, P=0.016). Conclusions For patients undergoing nasal feeding who are older than 80 years, the fasting and 1-hour postprandial pepsin concentration were consistent. Diabetes and feeding methods are risk factors for high pepsin levels. For the elderly over 80 years old, age has no influence on pepsin concentration.

Does Pepsin Saliva Concentration (Peptest™) Predict the Therapeutic Response of Laryngopharyngeal Reflux Patients?

To study the profile and the therapeutic response of patients with laryngopharyngeal reflux (LPR) at the hypopharyngeal-esophageal multichannel intraluminal impedance-pH monitoring (HEMII-pH) according to the initial pepsin saliva concentration. From January 2018 to January 2020, patients with positive LPR diagnosis at the HEMII-pH were consecutively recruited from 3 European Hospitals. Saliva pepsin concentration (Peptest™) was measured during the HEMII-pH testing period and patients were classified into 2 groups: negative versus positive Peptest. The clinical outcomes, that is, gastrointestinal and HEMII-pH findings, reflux symptom score-12 (RSS-12), and 3-month therapeutic response, were compared between groups. A total of 124 patients completed the study. Among them, 30 patients had negative Peptest. Pharyngeal reflux events occurred outside 1-hour post-meal time in 74.0%, after the meals in 20.5% and nighttime in 5.5%. The pepsin saliva level was not significantly associated with the reflux events preceding the sample collection. Patients with positive Peptest had better improvement of RSS-12 digestive and respiratory subscores and oral, pharyngeal, and laryngeal findings compared with patients with negative Peptest. Patients with high saliva pepsin concentration had no stronger gastrointestinal, HEMII-pH, or clinical outcomes compared with those with low or undetectable saliva pepsin concentration.

Bioinspired proteolytic membrane (BPM) with bilayer pepsin structure for protein hydrolysis

Peptides derived from food proteins exhibit a great application potential as natural health product. Conventional enzymatic membrane reactor for peptides production bears some disadvantages, such as high membrane fouling, clear enzyme leaching, and low operational stability. Herein, the bioinspired proteolytic membrane (BPM) with bilayer pepsin structure was fabricated to produce the peptides via reverse filtration and layered immobilization (polydopamine coating and polyethyleneimine grafting). The results of Fourier transform infrared spectroscopy and Emission scanning electron microscopy found that BPM could stably form 3 different structures by various fabrication methods: monolayer reverse proteolytic membrane (MR-PM), monolayer reverse bioinspired proteolytic membrane (MR-BPM) and bilayer reverse bioinspired proteolytic membrane (BR-BPM). Besides, with the increase of enzyme layers, the enzyme loading, enzyme activity and degree of hydrolysis BPM considerably improved. Then, BR-BPM filtration tests were conducted under various operation conditions (transmembrane pressure (TMP) (1–4 bar) and pepsin concentration (0.1–0.9 mg/mL)). BR-BPM acquired the higher enzyme loading, degree of hydrolysis (DH) and permeate flux than MR-PM and MR-BPM by bilayer pepsin structure. In addition, BR-BPM demonstrated the great filtration performance (permeate flux = 6.5 L m−2 h−1 bar−1 and DH = 45.7%) for the long-term tests (four continuous filtration cycles) at the optimized condition (TMP = 3 bar and pepsin concentration = 0.5 mg/mL). This work offers a promising guideline of the fabrication of functional membrane for peptides production.

Identification and characterization of novel α-amylase and α-glucosidase inhibitory peptides from camel whey proteins

This study explores the inhibitory properties of camel whey protein hydrolysates (CWPH) toward α-amylase (AAM) and α-glucosidase (AG). A general full factorial design (3 × 3) was applied to study the effect of temperature (30, 37, and 45°C), time (120, 240, and 360 min), and enzyme (pepsin) concentration (E%; 0.5, 1, and 2%). The results showed that maximum degree of hydrolysis was obtained when hydrolysis was carried out at higher temperature (45°C; P < 0.05), compared with lower temperatures of 30 and 37°C. Electrophoretic pattern displays degradation of all protein bands upon hydrolysis by pepsin at various hydrolysis conditions applied. All the 27 CWPH generated showed significant AAM and AG inhibitory potential as indicated by their lower IC50 values (mg/mL) compared with intact whey proteins. In total 196 peptides were identified from selected hydrolysates and 15 potential peptides (PepSite score > 0.8; http://pepsite2.russelllab.org/) were explored via in silico approach. Novel peptides PAGNFLMNGLMHR, PAVACCLPPLPCHM, MLPLMLPFTMGY, and PAGNFLPPVAAAPVM were identified as potential inhibitors for both AAM and AG due to their high number of binding sites and highest binding probability toward the target enzymes. CCGM and MFE, as well as FCCLGPVPP were identified as AG and AAM inhibitory peptides, respectively. This is the first study that reports novel AG and AAM inhibitory peptides from camel whey proteins. The future direction for this research involves synthesis of these potential AG and AAM inhibitory peptides in a pure form and investigate their antidiabetic properties in the in vitro, as well as in vivo models. Thus, CWPH can be considered for potential applications in glycaemic regulation.

Transesophageal echocardiography-associated tracheal microaspiration and ventilator-associated pneumonia in intubated critically ill patients: a multicenter prospective observational study

BackgroundMicroaspiration of gastric and oropharyngeal secretions is the main causative mechanism of ventilator-associated pneumonia (VAP). Transesophageal echocardiography (TEE) is a routine investigation tool in intensive care unit and could enhance microaspiration. This study aimed at evaluating the impact of TEE on microaspiration and VAP in intubated critically ill adult patients.MethodsIt is a four-center prospective observational study. Microaspiration biomarkers (pepsin and salivary amylase) concentrations were quantitatively measured on tracheal aspirates drawn before and after TEE. The primary endpoint was the percentage of patients with TEE-associated microaspiration, defined as: (1) ≥ 50% increase in biomarker concentration between pre-TEE and post-TEE samples, and (2) a significant post-TEE biomarker concentration (> 200 μg/L for pepsin and/or > 1685 IU/L for salivary amylase). Secondary endpoints included the development of VAP within three days after TEE and the evolution of tracheal cuff pressure throughout TEE.ResultsWe enrolled 100 patients (35 females), with a median age of 64 (53–72) years. Of the 74 patients analyzed for biomarkers, 17 (23%) got TEE-associated microaspiration. However, overall, pepsin and salivary amylase levels were not significantly different between before and after TEE, with wide interindividual variability. VAP occurred in 19 patients (19%) within 3 days following TEE. VAP patients had a larger tracheal tube size and endured more attempts of TEE probe introduction than their counterparts but showed similar aspiration biomarker concentrations. TEE induced an increase in tracheal cuff pressure, especially during insertion and removal of the probe.ConclusionsWe could not find any association between TEE-associated microaspiration and the development of VAP during the three days following TEE in intubated critically ill patients. However, our study cannot formally rule out a role for TEE because of the high rate of VAP observed after TEE and the limitations of our methods.

The Role of Salivary Pepsin in the Diagnosis of Gastroesophageal Reflux Disease (GERD) Evaluated Using High-Resolution Manometry and 24-Hour Multichannel Intraluminal Impedance-pH Monitoring.

BackgroundThe Lyon Consensus classification confirms or rules out gastroesophageal reflux disease (GERD). The refractory symptoms of patients with GERD taking proton pump inhibitors (PPIs) are challenging in clinical practice. Salivary pepsin concentration was proposed as a diagnostic biomarker for GERD. We aimed to determine the diagnostic value of salivary pepsin concentration for patients with conclusive GERD, based on the Lyon classification, and the correlation of salivary pepsin concentration with parameters of high-resolution manometry and 24-h multichannel intraluminal impedance-pH in patients with PPI-refractory symptoms.Material/MethodsSaliva samples obtained from 130 patients who were suspicious for GERD and had PPI-refractory symptoms were used for pepsin determination using the enzyme-linked immunosorbent assay. All patients underwent upper gastrointestinal endoscopy, high-resolution manometry, 24-h multichannel intraluminal impedance, and pH recording and were classified as conclusive GERD, inconclusive GERD, and evidence against GERD groups according to Lyon classification.ResultsSalivary pepsin concentration was 8.2 ng/mL (3.8–17.8 ng/mL), 4.0 ng/mL (2.3–6.1 ng/mL), and 2.4 ng/mL (2.2–3.1 ng/mL) in conclusive GERD, inconclusive GERD, and evidence against GERD groups, respectively (P<0.001), and had a negative correlation with distal mean nocturnal baseline impedance and positive correlations with acid exposure time, total number of reflux events, and esophagogastric junction type. The area under the ROC curve of salivary pepsin for conclusive GERD was 0.76 (0.68–0.84), with a sensitivity of 76.36% and a specificity of 63.41% for conclusive GERD diagnosis at a cut-off value of 4.21 ng/mL.ConclusionsSalivary pepsin test had moderate diagnostic value for conclusive GERD by Lyon classification in patients with PPI-refractory symptoms.

Diagnostic performance of salivary pepsin for gastroesophageal reflux disease.

Uncertain diagnostic performance has limited clinical adoption of salivary pepsin, a noninvasive diagnostic tool for gastroesophageal reflux disease (GERD). This study aimed to assess diagnostic performance of salivary pepsin, and test validity of thresholds in an external cohort of patients with or without GERD. This two-phase prospective study conducted at two centers enrolled adult asymptomatic volunteers, patients with symptoms of GERD undergoing reflux monitoring, and patients with Barrett's esophagus (BE). Fasting saliva samples were processed for pepsin concentration using Peptest. Phase 1 compared pepsin concentration between No GERD (volunteers/functional heartburn) and GERD (erosive reflux disease/nonerosive reflux disease (NERD)/BE). Phase 2 tested validity of the diagnostic thresholds identified from Phase 1 among external functional heartburn and NERD cohorts. Of 243 enrolled subjects, 156 met inclusion criteria. Phase 1 (n = 114): Pepsin concentrations were significantly higher in GERD (n = 84) versus No GERD (n = 30) (73.8ng/mL vs. 21.1ng/mL; P < 0.001). Area under the curve for pepsin concentration was 0.74 (95% CI 0.65, 0.83). A salivary pepsin threshold of 24.9ng/mL optimized the true negative rate and 100.0ng/mL optimized the true positive rate. Phase 2 (n = 42): Pepsin concentrations were significantly higher in NERD (n = 22) versus Functional Heartburn (n = 20) (176.0ng/mL vs. 53.3ng/mL, P < 0.001). Applying Phase 1 thresholds in this external cohort, salivary pepsin 24.9ng/mL was 86% sensitive (64%, 97%) and 100.0ng/mL was 72% specific for distinguishing NERD from functional heartburn. Given modest sensitivity and specificity for GERD, salivary pepsin may have clinical utility as a noninvasive office based diagnostic screening tool for GERD.

Pepsin in gastroesophageal and extraesophageal reflux: molecular pathophysiology and diagnostic utility.

Gastroesophageal and extraesophageal reflux are prevalent and costly diseases. Recognition of the pathogenicity of nonacid reflux has stimulated interest in alternatives to acid-targeting diagnostics and therapeutics. Pepsin is the most deleterious enzyme in refluxate, eliciting inflammatory and carcinogenic effects irrespective of acid. Its presence in all refluxate and detection in saliva have situated pepsin as the most widely researched biomarker for reflux today. This review summarizes emerging findings regarding pepsin-mediated damage during reflux and developments in pepsin-targeting diagnostics. New evidence supports a role for pepsin in epithelial--mesenchymal transition, an important process in carcinogenesis and fibrosis. The first global transcriptomic analysis of pepsin-exposed laryngeal cells was described, yielding evidence of a putative airway pepsin receptor. Evaluation of pepsin diagnostics highlighted the need for rigorous validation in which pepsin concentrations are corroborated by a secondary quantitative assay, and reflux is confirmed or excluded by multichannel intraluminal impedance pH testing. Standards for sample collection and storage, and normative and pathological values are lacking. Progress continues to be made in our understanding of pepsin-mediated damage with implications for novel therapeutic strategies. Salivary pepsin diagnostics continue to garner interest; however, further work appears necessary to improve their accuracy and reproducibility.

Evidence of Pepsin-Related Ocular Surface Damage and Dry Eye (PROD Syndrome) in Patients with Laryngopharyngeal Reflux

Background: patients with laryngopharyngeal reflux (LPR) showed detectable levels of tear pepsin that explain the nasolacrimal obstruction. The purpose of this study was to determine whether patients with LPR show ocular surface changes and to investigate the relationship between lacrimal pepsin concentration and ocular alterations. Methods: Fifty patients with positive endoscopic signs for LPR and an equal or higher score of 13 and 7 for Reflux Symptom Index and Reflux Finding Score were enrolled. Twenty healthy patients with no reflux disease and dry eye were included as the control group. After evaluation of ocular discomfort symptoms, the tear break-up time test, corneal staining, and tear sampling were performed. Tear pepsin levels were measured using Pep-testTM kit. Results: Patients with LPR showed ocular surface changes including epithelial damage (48%) and impairment of lacrimal function (72%). Tear pepsin levels were detectable in 32 out of 50 (64%) patients with LPR (mean ± SD: 55.4 ± 67.5 ng/mL) and in none of the control subjects. Most of the LPR patients complained of ocular discomfort symptoms, including itching (38%), redness (56%), or foreign body sensation (40%). Tear pepsin levels were significantly correlated with the severity of LPR disease and with ocular surface changes. Conclusions: A multidisciplinary approach, including ophthalmological evaluation, should be considered in order to improve the management of patients with LPR.

Association of pepsin and DNA damage in laryngopharyngeal reflux-related vocal fold polyps.

This study aimed to evaluate if laryngopharyngeal reflux (LPR) plays a role as a risk factor for vocal fold polyps (VFPs), and if pepsin is associated with higher oxidative DNA damage of VFPs in the presence of LPR. Thirty patients with VFPs were recruited between 2017 and 2018. Prior to surgery, a laryngoscopy was performed on all subjects to evaluate VFPs. Polyp tissue and saliva samples were obtained scrupulously. Hematoxylin-eosin staining was performed for pathologic analysis. Immunohistochemistry and ELISA were used to detect pepsin in tissue and saliva of VFP patients. 8-OHdG and p-H2AX expression was detected to measure oxidative DNA damage in tissue. DNA damage was investigated in human immortalized laryngeal epithelial cells exposed to pepsin. The pepsin concentration in saliva was significantly higher (t=2.38, P=.024) in the pepsin positive group. There was no significant difference in pepsin expression at different sites and pathological subtypes of VFPs. The levels of 8-OHdG and p-H2AX were significantly higher in the pepsin positive group and positively correlated with the tissue expression of pepsin. The concentration of pepsin in saliva also showed a significant correlation with 8-OHdG levels. Expression of 8-OHdG and p-H2AX, and tail moment of the comet assay were elevated in human immortalized laryngeal epithelial cells following treatment with pepsin. Patients with VFPs have higher levels of oxidative DNA damage in the presence of pepsin reflux. Pepsin may induce DNA damage in laryngeal epithelial cells and participate in the pathogenesis of VFPs.

PHYSIOCHEMICAL PROPERTIES AND ACE INHIBITORY CAPACITY OF HAZELNUT PROTEIN ISOLATE AND HYDROLYSATES

Protein solubility, water holding capacity, fat absorption capacity, emulsion activity index, emulsion stability index, gel formation capacity and Angiotensin-Converting Enzyme (ACE) inhibitory capacity of hazelnut protein isolate (HPI) and its hydrolysate were determined. The results showed that protein solubility had U shape solubility profile with an isoelectric point at pH 4.5-5 and highest value at pH 2 and pH 10. Water holding capacity and fat absorption capacity of HPI was found as 1.95 mL water/g protein and 2.1 g fat/g protein, respectively. Emulsion activity index and emulsion stability index values were found as 44 m2/g and 46 min at pH 7.0, respectively. Weak gel formation of HPI was seen at 8% and firm gel (LGC) was observed at 12% protein concentration. The concentration of pepsin hydrolysates needed to inhibit 50% of the ACE activity values (IC50) at 0, 30, 60 and 120 min of hydrolysis were 1.47 mg protein/mL, 0.27 mg protein/mL, 0.27 mg protein/mL and 0.26 mg protein/mL respectively. Whereas, IC50 of trypsin hydrolysates at 0, 30, 60 and 120 min were 5.51 mg protein/mL, 0.61 mg protein/mL, 0.56 mg protein/mL and 0.54 mg protein/mL. These results showed that isolates and hydrolysates of hazelnut has valuable functional properties and noted as good candidates for effectively reducing hypertension.

4167 Peri-transplant Lung Microbiome Reveal Oral Bacteria, Pepsin And Inflammatory Markers Co-associate With Primary Graft Dysfunction, Implicating Aspiration As A Potential Contributor

OBJECTIVES/GOALS: Primary graft dysfunction (PGD) is acute lung injury in the first three days after lung transplant. Patients that experience PGD have increased mortality and an increased risk of chronic lung allograft dysfunction. The pathogenesis is thought to be an ischemia-reperfusion injury but is incompletely understood and there are no specific therapies. We investigated the role of the microbiome in PGD and associations with inflammation and markers of aspiration. METHODS/STUDY POPULATION: We collected airway lavage samples from lung transplant donors before procurement and recipients after reperfusion. We extracted DNA, amplified the bacterial 16S rRNA gene, and sequenced on the Illumina MiSeq platform. QIIME2 and Deblur were used for bioinformatic analysis. R packages were used for downstream analysis and visualizations. The host response was quantified using the Milipore 41-plex Luminex and an ELISA for pepsin. Clinical data was collected by the Penn Lung Transplant Outcomes Group. PGD was assessed by degree of hypoxemia and chest X-ray findings in the 72 hours after transplant. RESULTS/ANTICIPATED RESULTS: There was no significant difference in alpha diversity (Shannon index, p = 0.51), biomass (via comparison of 16S amplicon PicoGreen, p = 0.6), or beta diversity (Weighted UniFrac, p = 0.472, PERMANOVA) between subjects with PGD grade 3 (n = 36) and those that did not (n = 96). On taxonomic analysis, we found an enrichment of Prevotella in donor and recipient lungs that went on to develop PGD (p = 0.05). To follow up this finding we measured immune response and pepsin concentrations in recipient lungs. We found elevated levels in 35/41 cytokines measured in subjects that developed PGD as well as an elevation in pepsin and a correlation between pepsin concentration and Prevotella relative abundance (Figure 1). Additionally, Prevotella relative abundance had statistically significant positive correlations with multiple cytokines such as IL-6 (Pearson’s = 0.26, p = 0.009) and eotaxin (Pearson’s = 0.24, p = 0.016). DISCUSSION/SIGNIFICANCE OF IMPACT: There is an enrichment of oral anerobes in lung allografts that eventually develop PGD. This is associated with elevated levels of pepsin and markers of inflammation. These lines of evidence suggest aspiration contributes to priming the allograft for PGD.

Usefulness of Pep-Test for Laryngo-Pharyngeal Reflux: A Pilot Study in Primary Care.

BackgroundGastroesophageal reflux disease is a digestive disorder characterized by nausea, regurgitation, and heartburn. Gastroesophageal reflux is the primary cause of laryngeal symptoms, especially chronic posterior laryngitis. The best diagnostic test for this disease is esophageal impedance-pH monitoring; however, it is poorly employed owing to its high cost and invasiveness. Salivary pepsin measured using a lateral flow device (Pep-test) has been suggested as an indirect marker of laryngopharyngeal reflux (LPR). The present study tested the reliability of Pep-test in diagnosing LPR in uninvestigated primary care attenders presenting with chronic laryngeal symptoms, and evaluated the raw pepsin concentration in patients with LPR.MethodsA multicenter, non-interventional pilot study was conducted on 86 suspected patients with LPR and 59 asymptomatic subjects as controls in three Italian primary care settings. A reflux symptom index questionnaire was used to differentiate patients with LPR (score >13) from controls (score <5). Two saliva samples were collected, and comparisons between the groups were performed using two-sided statistical tests, according to variable distributions.ResultsThere was no statistical difference in the salivary pepsin positivity between LPR patients and controls, whereas the pepsin intensity value was higher in controls than in LPR patients.ConclusionA high prevalence of pepsin positivity was observed in asymptomatic controls. Pepsin measurement should not be considered as a diagnostic test for LPR in primary care patients.

Hypopharyngeal‐Esophageal Impedance‐pH Monitoring Profiles of Laryngopharyngeal Reflux Patients

To investigate the profile of patients with laryngopharyngeal reflux (LPR) at hypopharyngeal-esophageal multichannel intraluminal impedance-pH (HEMII-pH) monitoring and the relationship between hypopharyngeal-proximal reflux episodes (HREs) and saliva pepsin concentration. Prospective non-controlled. Patients were recruited from three European hospitals from January 2018 to October 2019. Patients benefited from HEMII-pH monitoring and saliva collections to measure saliva pepsin concentration in the same time. Saliva pepsin concentration was measured in the morning (fasting), after lunch, and after dinner. The LPR profile of patients was studied through a breakdown of the HEMII-pH findings over the 24 hours of testing. The relationship between the concentrations of saliva pepsin and 24-hour HREs was studied through linear multiple regression. One hundred twenty-six patients completed the study. The HEMII-pH analyses revealed that 73.99% of HREs occurred outside 1-hour postmeal times, whereas 20.49% and 5.52% of HREs occurred during the 1-hour postmeal and nighttime, respectively. Seventy-four patients (58.73%) did not have nighttime HREs. Patients with both daytime and nighttime HREs had more severe HEMII-pH parameters and reflux symptom score compared with patients with only daytime HREs. There were no significant associations between HREs and saliva pepsin concentration. Unlike gastroesophageal reflux disease, HREs occur less frequently after meals and nighttime. The analysis of the HEMII-pH profile of the LPR patients has to be considered to develop future personalized therapeutic strategies. 4 Laryngoscope, 131:268-276, 2021.

Pepsin and bile acids detection in saliva for the diagnosis of gastroesophageal reflux disease

Objective: To identify the value of the detection of pepsin and bile acids in saliva for the diagnosis of gastroesophageal reflux disease(GERD). Methods: From January 2018 to June 2019, 104 GERD patients and 43 healthy people in Guangdong Provincial People's Hospital were recruited. The 104 patients of GERD group were divided into four sub-groups, including esophageal symptoms GERD group, extraesophageal symptoms GERD group, anxiety or depression group, non-anxiety and non-depression group. Saliva was collected on waking in morning and 2 h after finishing lunch. The concentration of the total pepsin(TPP) and total bile acids(TBA) from saliva was detected by ELISA method. Receiver operating characteristics analysis was used to identify the sensitivity and specificity of the saliva pepsin and bile acids detection. Results: The concentration of TPP in morning waking samples and postprandial samples in the GERD group was 27.1(9.7,50.3) μg/L and 32.4(14.0,58.7) μg/L, the concentration of TBA in postprandial samples was (18.4±2.3)μmol/L, and these levels were significantly higher than that of the control group [7.0(5.1, 9.1) μg/L, 7.4(5.2, 9.4) μg/L, (12.6±5.0)μmol/L](P<0.01). The concentration of TBA in morning waking samples had no significant difference between these two groups(P>0.05). The concentration of TPP and TBA had no significant difference among the four GERD sub-groups(P>0.05).Pepsin in postprandial saliva samples had moderate diagnostic value for GERD, when the saliva pepsin concentration in postprandial samples was higher than 41.33 μg/L, it had a sensitivity of 82.8% and a specificity of 73.3%. The bile acids in saliva had no significant diagnostic value for GERD. Conclusions: Pepsin detection in saliva has a high level of sensitivity and specificity for diagnosing GERD. However, bile acids in saliva has no significant diagnostic value for GERD.

Isolation and characterization of collagen from local goat bone using pepsin hydrolysis

Goat bone is one of by-product which has not commonly used in Indonesia. Collagen is one of proteins which contained a bone which characterizing its uniq function. The purpose of experiment was to isolate and characterize collagen from local goat bone with pepsin enzymatic hydrolysis in various concentration. The experiment consisted of bone preparation, Isolating by leaching method, and the hydrolysis of collagen bone using pepsin enzyme in various concentration (0.1; 0.3; 0.5; and 1%). Variables observed were collagen yield, soluble protein, pH, Fourier Tansform Infrared Spectroscopy (FTIR) spectra, thermal stability using Differential Scanning Calorimetry (DSC), and molecular weight using Sodium Dodesyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE). The results showed that soluble protein concentration of collagen solution was not affected by pepsin concentrations. The soluble protein of 0.1; 0.3; 0.5 and 1 % of enzym were 0.203±0,013; 0.244±0,045; 0.295±0,065; and 0.257±0,066 mg/ml for, respectively. The results of collagen yield was significant, and it were 7.12; 7.54; 13.3; dan 8.81 %. The results of pH showed significant, it was 6.37; 5.96; 6.88; 5.92. The FTIR spectra showed that all of the sample has not changed into gelatin. The thermal stability in DSC analysis showed that the collagen start to gelation at 56.72 to 57.40 °C and Tmax for each sample were 128.20; 189.32; 131.35; 124.43 °C, respectively. In conclusion, collagen could be isolated from goat bone using enzymatic treatment and showed the fine properties as well as collagen from skin.

Improvement in Entrapment Efficiency and In Vitro Digestion Stability of Lutein by Zein Nanocarriers with Pepsin Hydrolysis

Zein is one of the popular bioactive carriers and play critical roles in the promotion of stability, absorption, and utilization of the nutrients and bioactive ingredients. The application of zein delivery systems for the encapsulation of bioactive ingredients has recently gained increasing interest. The aim of this work was to modify zein by pepsin and prepare the lutein-loaded zein nanoparticle (LZN) and the lutein-loaded zein hydrolysate nanoparticle (LZHN), respectively. The effects of zein hydrolysation on entrapment efficiency and in vitro digestion stability of lutein were also evaluated in this study. Hydrolysation of zein by the pepsin has important effects on lutein embedding. The optimal hydrolysis conditions, including the pepsin concentration (1.5%), temperature (55°C), and time (4 h), enhanced the entrapment efficiency (EE) of lutein by 93.82 ± 2.82% as compared to 85.18 ± 3.28% of the untreated zein, respectively. In contrast to LZN, LZHN had better structural characteristics, the average particle size decreases from 158.40 ± 3.22 nm to 112.2 ± 1.56 nm, and LZHN showed better dispersivity and zeta potential. The stability and release assays in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) showed that hydrolyzed zein nanocarriers by pepsin improved the digestion stability and promoted the release of lutein under gastrointestinal digestive conditions. These results suggest that hydrolyzed zein with pepsin may act as an effective carrier for lutein delivery and shows many potential advantages compared with the zein.

Gold nanoparticles-functionalized monolithic column for enantioseparation of eight basic chiral drugs by capillary electrochromatography.

Poly(glycidyl methacrylate)-co-(ethylene dimethacrylate) [poly(GMA-co-EDMA)] monoliths were prepared, and used as a support to attach gold nanoparticles (AuNP) via Au-S bond. Pepsin, acting as a chiral selector, was linked to the surface of the carboxyl-modified AuNP through a hydrochloride/N-hydroxysuccinimide coupling reaction. The material was characterized by scanning electron microscopy, energy dispersive X-ray spectrometry, transmission electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy and N2 adsorption-desorption isotherm. The pepsin@AuNP@poly(GMA-co-EDMA) monolith showed preferable enantioselectivity for hydroxychloroquine (HCQ), chloroquine (CHQ), hydroxyzine (HXY), labetalol (LAB), nefopam (NEF), clenbuterol (CLE), amlodipine (AML) and chlorpheniramine (CHL) in capillary electrochromatography (CEC). These racemic drugs were monitored at the maximum absorption wavelength (220nm for HXQ, CHQ, HXY, LAB, NEF; 240nm for AML; 215nm for CLE, CHL). In comparison with the pepsin@poly(GMA-co-EDMA) monolith loaded with 5nm AuNP, the pepsin@poly(GMA-co-EDMA) monolith loaded with 13nm AuNP shows significantly enhanced enantiomeric resolution (HCQ: 0.62 → 3.45; CHQ: 0.60 → 2.11; HXY: 0.49 → 2.30; LAB: 1.03 → 2.45, 1.45 → 3.46, 0 → 0.67; NEF: 0.53 → 1.29; CLE: 0.42 → 0.56; AML: 0 → 0.83; CHL: 0.24 → 0.55). Pepsin concentration, buffer pH value, buffer concentration and applied voltage were investigated in detailwith (±) HCQ and (±) HXY as model analytes. The reproducibility of intra-day, inter-day and column-to-column were explored, and found to be satisfactory. Graphical abstractSchematic presentation of the preparation of gold nanoparticles (AuNP) modified.

Salivary Pepsin as an Intrinsic Marker for Diagnosis of Sub-types of Gastroesophageal Reflux Disease and Gastroesophageal Reflux Disease-related Disorders.

Background/AimsTo determine the value of salivary pepsin in discriminating sub-types of gastroesophageal reflux disease (GERD) and GERD-related disorders.MethodsOverall, 322 patients with different sub-types of GERD and 45 healthy controls (HC) were studied. All patients took Gastroesophageal Reflux Disease Questionnaire (GerdQ) and underwent endoscopy and 24-hour esophageal pH monitoring and manometry. Salivary pepsin concentration (SPC) was detected by using colloidal gold double-antibody immunological sandwich assay. Oral esomeprazole treatment was administrated in the patients with non-erosive reflux disease (NERD) and extra-esophageal symptoms (EES).ResultsCompared to HC, patients with erosive esophagitis, NERD, EES, EES plus typical GERD symptoms, or Barrett’s esophagus had a higher prevalence of saliva and SPC (all P < 0.001). There was no significant difference in the positive rate for pepsin in patients with functional heartburn or GERD with anxiety and depression, compared to HC. After esomeprazole treatment, the positive rate and SPC were significantly reduced in NERD (both P < 0.001) and in EES (P = 0.001 and P = 0.002, respectively). Of the 64 NERD patients, 71.9% (n = 46) were positive for salivary pepsin, which was significantly higher than the rate (43.8%, n = 28) of pathological acid reflux as detected by 24-hour esophageal pH monitoring (P = 0.002).ConclusionsSalivary pepsin has an important significance for the diagnosis of GERD and GERD-related disorders. Salivary pepsin and 24-hour esophageal pH monitoring may complement with each other to improve the diagnostic efficiency.