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International Journal of Biological... Dec 2023Pepsin is a proteolytic enzyme used in the treatment of digestive disorders. In this study, we investigated the physicochemical properties of the...
Pepsin is a proteolytic enzyme used in the treatment of digestive disorders. In this study, we investigated the physicochemical properties of the tetradecyltrimethylammonium bromide (TTAB) and pepsin protein mixture in various sodium salt media within a temperature range of 300.55-320.55 K with 5 K intervals. The conductometric study of the TTAB+pepsin mixture revealed a reduction in the critical micelle concentration (CMC) in electrolyte media. The micellization of TTAB was delayed in the presence of pepsin. The CMC of the TTAB + pepsin mixture was found to depend on the concentrations of electrolytes and protein, as well as the temperature variations. The aggregation of the TTAB+pepsin mixture was hindered as a function of [pepsin] and increasing temperatures, while micellization was promoted in aqueous electrolyte solutions. The negative free energy changes (∆G) indicated the spontaneous aggregation of the TTAB+pepsin mixture. Changes in enthalpy, entropy, molar heat capacities, transfer properties, and enthalpy-entropy compensation variables were calculated and illustrated rationally. The interaction forces between TTAB and pepsin protein in the experimental solvents were primarily hydrophobic and electrostatic (ion-dipole) in nature. An analysis of molecular docking revealed hydrophobic interactions as the main stabilizing forces in the TTAB-pepsin complex.
Topics: Pepsin A; Sodium; Molecular Docking Simulation; Water; Micelles
PubMed: 37866567
DOI: 10.1016/j.ijbiomac.2023.127478 -
Journal of Otolaryngology - Head & Neck... Oct 2023To investigate the association between obstructive sleep apnea (OSA) and laryngopharyngeal reflux (LPR) through oropharyngeal pH-monitoring and pepsin saliva...
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.
Topics: Humans; Saliva; Pepsin A; Prospective Studies; Laryngopharyngeal Reflux; Sleep Apnea, Obstructive; Hydrogen-Ion Concentration
PubMed: 37838710
DOI: 10.1186/s40463-023-00675-0 -
Biomaterials Nov 2023Idiopathic Pulmonary Fibrosis (IPF) is a progressively debilitating lung condition characterized by oxidative stress, cell phenotype shifts, and excessive extracellular...
Idiopathic Pulmonary Fibrosis (IPF) is a progressively debilitating lung condition characterized by oxidative stress, cell phenotype shifts, and excessive extracellular matrix (ECM) deposition. Recent studies have shown promising results using decellularized ECM-derived hydrogels produced through pepsin digestion in various lung injury models and even a human clinical trial for myocardial infarction. This study aimed to characterize the composition of ECM-derived hydrogels, assess their potential to prevent fibrosis in bleomycin-induced IPF models, and unravel their underlying molecular mechanisms of action. Porcine lungs were decellularized and pepsin-digested for 48 h. The hydrogel production process, including visualization of protein molecular weight distribution and hydrogel gelation, was characterized. Peptidomics analysis of ECM-derived hydrogel contained peptides from 224 proteins. Probable bioactive and cell-penetrating peptides, including collagen IV, laminin beta 2, and actin alpha 1, were identified. ECM-derived hydrogel treatment was administered as an early intervention to prevent fibrosis advancement in rat models of bleomycin-induced pulmonary fibrosis. ECM-derived hydrogel concentrations of 1 mg/mL and 2 mg/mL showed subtle but noticeable effects on reducing lung inflammation, oxidative damage, and protein markers related to fibrosis (e.g., alpha-smooth muscle actin, collagen I). Moreover, distinct changes were observed in macroscopic appearance, alveolar structure, collagen deposition, and protein expression between lungs that received ECM-derived hydrogel and control fibrotic lungs. Proteomic analyses revealed significant protein and gene expression changes related to cellular processes, pathways, and components involved in tissue remodeling, inflammation, and cytoskeleton regulation. RNA sequencing highlighted differentially expressed genes associated with various cellular processes, such as tissue remodeling, hormone secretion, cell chemotaxis, and cytoskeleton engagement. This study suggests that ECM-derived hydrogel treatment influence pathways associated with tissue repair, inflammation regulation, cytoskeleton reorganization, and cellular response to injury, potentially offering therapeutic benefits in preventing or mitigating lung fibrosis.
Topics: Swine; Rats; Humans; Animals; Hydrogels; Actins; Pepsin A; Proteomics; Extracellular Matrix; Idiopathic Pulmonary Fibrosis; Lung; Fibrosis; Collagen; Inflammation; Bleomycin
PubMed: 37820517
DOI: 10.1016/j.biomaterials.2023.122338 -
Food Research International (Ottawa,... Nov 2023The roles of protein composition, pH and enzymes in goat milk protein hydrolysis is still unclear and the proteolysis of low abundant goat milk proteins has received...
The roles of protein composition, pH and enzymes in goat milk protein hydrolysis is still unclear and the proteolysis of low abundant goat milk proteins has received limited attention. The aim of this study was to study the impact of protein composition and proteolytic conditions on goat milk protein hydrolysis in a simplified digestion model. Both whole milk and infant formula were hydrolyzed at pH 2 and 4, using pepsin as well as pepsin combined with pancreatin. Intact proteins were separated from digests using spin filters, followed by bottom-up proteomics of the separated proteins. Results show that under all conditions, caseins are hydrolyzed quickly. Goat casein hydrolysis in infant formula was slightly faster than in goat whole milk, possibly due to less casein coagulation during pepsin hydrolysis at both pH 2 and 4. Several low abundant immunoactive goat milk proteins, especially immunoglobulins, GLYCAM-1 and osteopontin, resisted proteolysis more than high abundant proteins, independent of the pH and enzyme used for hydrolysis. Fast hydrolysis of casein and slow hydrolysis of immunoactive proteins may indicate a good balance between protein utilization and protection of the infant by goat milk proteins.
Topics: Animals; Infant; Humans; Milk Proteins; Proteolysis; Pancreatin; Caseins; Pepsin A; Goats; Hydrogen-Ion Concentration
PubMed: 37803606
DOI: 10.1016/j.foodres.2023.113294 -
Journal of Otolaryngology - Head & Neck... Oct 2023To study the variability and diagnostic value of multiple salivary pepsin measurements in the detection of laryngopharyngeal reflux (LPR).
OBJECTIVE
To study the variability and diagnostic value of multiple salivary pepsin measurements in the detection of laryngopharyngeal reflux (LPR).
METHODS
Patients with LPR symptoms were consecutively recruited from December 2019 to Augustus 2022. Twenty-one asymptomatic individuals completed the study. The diagnostic was confirmed with hypopharyngeal-esophageal impedance-pH monitoring (HEMII-pH). Patients collected three saliva samples during the 24-h testing period. Symptoms and findings were studied with reflux symptom score-12 and reflux sign assessment. Sensitivity, specificity, positive (PPV) and negative (NPV) predictive values of pepsin measurements were calculated considering morning, post-lunch and post-dinner samples. The consistency and relationship between HEMII-pH, pepsin measurements, and clinical features were investigated.
RESULTS
Morning, post-lunch and post-dinner saliva pepsin concentrations were measured in 42 patients. Pepsin measurements were 64.9%, 59.5%, and 59.0% sensitive for morning, post-lunch and post-dinner collections at cutoff ≥ 16 ng/mL. Considering the highest concentration of the three pepsin saliva collections, the accuracy, sensitivity, specificity and PPV were 70.5%, 73.0%; 66.7% and 78.9%, respectively. Morning pepsin measurements reported higher consistency, sensitivity, and specificity than post-dinner and post-lunch pepsin measurements.
CONCLUSION
The collection of several saliva pepsin samples improves the detection rate of LPR. In case of high clinical LPR suspicion and negative pepsin test, a HEMII-pH study could provide further diagnostic information.
Topics: Humans; Laryngopharyngeal Reflux; Saliva; Pepsin A; Prospective Studies; Esophageal pH Monitoring
PubMed: 37794462
DOI: 10.1186/s40463-023-00670-5 -
Journal of Ethnopharmacology Jan 2024Huang-Qi-Jian-Zhong-Tang (HQJZT) is a canonical traditional Chinese medicine (TCM) formula that has been widely used in both the prevention and treatment of...
ETHNOPHARMACOLOGICAL RELEVANCE
Huang-Qi-Jian-Zhong-Tang (HQJZT) is a canonical traditional Chinese medicine (TCM) formula that has been widely used in both the prevention and treatment of gastrointestinal diseases, including gastric ulcer, duodenal ulcer, and chronic atrophic gastritis, in China.
AIM OF THE STUDY
In the present study, we investigated the gastroprotective potential of HQJZT in a rat model of indomethacin (IND)-induced gastric ulcer and explained the biochemical, cellular, and molecular mechanisms involved.
MATERIALS AND METHODS
Observations were conducted at the macroscopic level to ascertain the ulcer index (UI) and the curative index (CI). Histopathological examinations were conducted, and a microscopic score (MS) was computed. The gastric juice volume, total acidity, pH value, and pepsin activity were quantified. Antioxidant and oxidative parameters were assessed, namely GSH, CAT, SOD, and MDA content. The RFLSI Pro instrument was employed to measure the blood flow within the gastric mucosa continuously. The mRNA levels of the inflammatory cytokines were assessed using droplet digital PCR (ddPCR). Molecular docking was employed to examine the interaction between representative active components of HQJZT and the binding sites associated with the NF-κB and STAT signaling pathways. The protein expression and localization of p-JAK, p-STAT, p-IκBβ, and p-NF-κB were evaluated through immunofluorescence analysis.
RESULTS
The administration of HQJZT treatment demonstrated a significant reduction in gastric lesions induced by IND, leading to a notable decrease in the UI. Additionally, HQJZT treatment significantly decreased gastric juice volume, acidity, and pepsin activity, accompanied by increased pH value. IND-treated stomachs exhibited severe hemorrhagic necrosis, submucosal edema, and epithelial cell destruction. However, the administration of HQJZT effectively counteracted these pathological changes. Furthermore, HQJZT administration significantly increased blood flow to the gastric mucosa. HQJZT enhanced antioxidant defenses and modulated oxidative stress by increasing SOD, CAT, and GSH activities while reducing MDA levels. Moreover, HQJZT reversed IND-induced increases in mRNA expression levels of inflammatory cytokines. Molecular docking analysis revealed that the representative active components of HQJZT could bind to the NF-κB and STAT signaling pathways. In addition, immunofluorescence microscopy revealed that HQJZT markedly attenuated the phosphorylation of IκΒβ, NF-κB, JAK, and STAT.
CONCLUSIONS
The therapeutic and protective effect of HQJZT on gastric ulcers is attributed to its ability to suppress gastric acid secretion, enhance antioxidative defenses and blood flow, mitigate proinflammatory cytokines, and inhibit the activation of NF-κB and STAT signaling pathways.
Topics: Rats; Animals; Indomethacin; Antioxidants; Stomach Ulcer; NF-kappa B; Pepsin A; Molecular Docking Simulation; Anti-Ulcer Agents; Anti-Inflammatory Agents; Gastric Mucosa; Cytokines; Superoxide Dismutase; RNA, Messenger
PubMed: 37783407
DOI: 10.1016/j.jep.2023.117264 -
International Journal of Biological... Dec 2023In this work, four structurally similar flavonols (galangin, kaempferol, quercetin and myricetin) were coated on the surface of...
In this work, four structurally similar flavonols (galangin, kaempferol, quercetin and myricetin) were coated on the surface of (11-mercaptoundecyl)-N,N,N-trimethylammonium bromide (MUTAB)‑gold nanoparticles (AuNPs) by two-step phase transfer and self-assembly, and the cationic MUTAB- AuNPs coated with flavonols (flavonol-MUTAB-AuNPs) were designed. Free radical scavenging and antibacterial experiments show that flavonol-MUTAB-AuNPs greatly improve the scavenging effect on DPPH, hydroxyl and superoxide anion radicals, and significantly enhance the inhibition effect on Staphylococcus aureus and Escherichia coli compared with flavonols and AuNPs. Then γ-globulin, fibrinogen, trypsin and pepsin were selected as representative proteins and their interaction with flavonol-MUTAB-AuNPs were investigated by various spectroscopic techniques. The fluorescence quenching mechanism of these four proteins by flavonol-MUTAB-AuNPs is static quenching. The binding constants K between them are in the range of 10 to 10. The interaction between them is endothermic, entropy-driven spontaneous process, and the main non-covalent force is the hydrophobic interaction. The effect of flavonol-MUTAB-AuNPs on the structure of the four proteins were investigated using UV-vis absorption spectra, synchronous fluorescence spectra and circular dichroism spectra. These results offer important insights into the essence of the interaction between flavonol-MUTAB-AuNPs and γ-globulin/fibrinogen/trypsin/pepsin. They will contribute to the development of safe and effective flavonol-MUTAB-AuNPs in biomedical fields.
Topics: Gold; Antioxidants; Pepsin A; Trypsin; Metal Nanoparticles; Flavonols; Anti-Bacterial Agents; Fibrinogen; gamma-Globulins
PubMed: 37769767
DOI: 10.1016/j.ijbiomac.2023.127074 -
Spectrochimica Acta. Part A, Molecular... Jan 2024Vildagliptin (VDG) and Metformin (Met) belong to a class of dipeptidylpeptidase-4 (DPP-4) inhibitor and biguanide, respectively and used for the management of diabetes...
Vildagliptin (VDG) and Metformin (Met) belong to a class of dipeptidylpeptidase-4 (DPP-4) inhibitor and biguanide, respectively and used for the management of diabetes mellitus type II (DMTII). Both the drugs are orally available which leads to various side effects due to its oral ingestion. Occurrence of these side effects might be due to some interactions with pepsin at a molecular level. Therefore, in order to investigate these interactions, multi-spectroscopic and in-silico techniques have been extensively studied to identify the binding characteristics of VDG with pepsin. Fluorescence data suggested that the quenching is due to dynamic and static mechanism and static was dominant one. However, fluorescence and UV-Vis spectroscopic measurement analysis suggested that VDG tends to associate with pepsin, via ground-state complex formation. Fluorescence study revealed the binding-constant value which was found to be 0.559 × 10 M at 298.15 K that is non-covalent in nature. VDG-pepsin complex shows exothermic and spontaneous binding as confirmed by the calculated values of ΔH, ΔS, and ΔG, are majorly caused by van der Waals forces and H-bonding interactions. CD spectra of pepsin in presence of VDG confirmed post binding conformational change. Enzyme-activity assay showed that activity of pepsin was decreased by upto 28 %. FRET analysis suggested that energy transfer efficiency is negligible for VDG-pepsin interaction. In-silico analysis reveals that H-bonding and electrostatic negative forces are the significant driving forces involved in the interaction of VDG and pepsin.
Topics: Spectrometry, Fluorescence; Binding Sites; Pepsin A; Vildagliptin; Metformin; Molecular Docking Simulation; Protein Binding; Thermodynamics; Circular Dichroism
PubMed: 37748335
DOI: 10.1016/j.saa.2023.123368 -
Environment International Sep 2023Microplastics residues in natural waters can adsorb organic contaminants owing to their rough surface morphology and high specific surface area, potentially harming...
Microplastics residues in natural waters can adsorb organic contaminants owing to their rough surface morphology and high specific surface area, potentially harming human health when ingested. Although humans inevitably ingest microplastics, the bioaccessibility of microplastic-associated chemicals in the human gastric and intestinal fluids remains unresolved. This study investigated the mechanism and primary factor controlling the bioaccessibility of polypropylene (PP) microplastic fiber-associated tetracycline (TC) and ciprofloxacin (CIP) in simulated human gastrointestinal fluids. After mixing 0.1 g of PP microfiber with 10 mg/L of TC (or CIP) for 96 h and exposure to simulated human gastrointestinal fluids, the TC concentrations were 0.440, 0.678, and 1.840 mg/L and the CIP concentrations were 0.700, 1.367, and 3.281 mg/L CIP in the simulated human saliva, gastric, and intestinal fluids after incubation for 60 s, 4 h, and 8 h, respectively. This indicated that the antibiotics TC and CIP adsorbed onto microfiber surface are readily released into human gastrointestinal fluids upon ingestion. Gastric and intestinal fluids showed enhanced bioaccessibility to TC/CIP adhered to PP microfiber. The primary factors affecting the bioaccessibility to TC/CIP adhered to PP microfiber surfaces were found to be pepsin in human gastric fluid and trypsin in human intestinal fluid. Molecular docking and simulated molecular dynamic analyses results showed that pepsin and trypsin stablish connections with TC via hydrogen bonds (reaction sites: pepsin TC: T, T, S, D, D and Y; trypsin TC: S, H, K, G, and G) and CIP via hydrophobic interactions (reaction sites: pepsin CIP: Y, T, T, F, I, V, and I; trypsin CIP: W, I, C, and C). Our findings highlight that microplastic ingestion increases the risk of microplastics and the co-contaminants adsorbed to human health; thus, these findings are helpful to assess the risk of microplastics and co-contaminants to human health.
Topics: Humans; Ciprofloxacin; Microplastics; Plastics; Polypropylenes; Molecular Docking Simulation; Pepsin A; Trypsin; Anti-Bacterial Agents; Tetracycline
PubMed: 37703772
DOI: 10.1016/j.envint.2023.108193 -
BMC Pulmonary Medicine Sep 2023Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) lung infection has represented a global challenge. Intriguingly, it has been shown that the alveolar lung...
BACKGROUND
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) lung infection has represented a global challenge. Intriguingly, it has been shown that the alveolar lung epithelium expresses little Angiotensin Converting Enzyme receptor protein (ACE2), the entry receptor for SARS-CoV-2. Upper airway establishment of infection and translocation to the lung is well documented but other anatomical niches may be relevant to potentially serious lung infection. ACE2 is heavily expressed in the gastrointestinal tract and gastrointestinal symptoms support a clinical diagnosis of Coronavirus disease 2019 (COVID-19). This suggests a research question and the need to gather patient data exploring potential aerodigestive links in SARS-CoV-2 tranlocation and infection which may be relevant in the peripheral lung. This recognizes anatomical proximity and concepts of bi-directional movement between the Gastrointestinal and lung systems in normal physiology and disease. We have therefore explored the potential for gastro oesophageal reflux disease (GORD) micro aspiration and aeorodigestive pathophysiology in a novel prospective investigation of patients hospitalized with COVID-19.
METHODS
This is a prospective descriptive cohort study of 210 patients who were hospitalized with a confirmed diagnosis of COVID-19. The cohort was divided into three groups of patients based on symptom severity and radiological results. The Reflux Symptom Index (RSI) was used to evaluate the presence and severity of GOR. An RSI greater than 13 is considered to be abnormal. Patients' saliva samples were tested using enzyme-linked immunosorbent assay (ELISA) to determine the level of salivary pepsin among the cohort of patients.
RESULTS
A total of 210 patients with COVID-19 were enrolled in the study with 55.2% (116/210) classified as mildly ill, 31.9% (67/210) moderately ill and 12.9% (27/210) as severely ill. 34% (72/210) of the patients had an RSI score of over 13 and a median salivary pepsin value of 54 ± 29 ng/ml which suggested an incidence of extraesophageal reflux (EOR) in around a third of patients. The presence of respiratory comorbid conditions, an RSI score of over 13 and a salivary pepsin level of > 76ng/ml increased the risk of developing a more severe COVID-19 infection.
CONCLUSION
The study showed a high prevalence of EOR among the study cohort and provide the first prospective evidence suggesting the potential for aerodigestive pathophysiology including microaspiration in COVID-19 disease. We believe that the results of our study support the need for more extensive research.
Topics: Humans; COVID-19; Prospective Studies; SARS-CoV-2; Jordan; Angiotensin-Converting Enzyme 2; Cohort Studies; Pepsin A; Gastroesophageal Reflux
PubMed: 37697259
DOI: 10.1186/s12890-023-02638-7