-
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 -
Molecules (Basel, Switzerland) Aug 2023The lysozyme in the chicken egg white consists of various bioactive amino acids. However, these compounds are inactive when they are in the sequence of parent proteins....
The lysozyme in the chicken egg white consists of various bioactive amino acids. However, these compounds are inactive when they are in the sequence of parent proteins. They become active only when isolated from these proteins. The aim of this study was to modify lysozyme with proteolytic enzymes under specific conditions of the reaction environment so as to obtain active biopeptides. The physicochemical properties of the resulting preparations were also assessed. Our study showed that the modification of lysozyme with hydrolytic enzymes (pepsin and trypsin) under strictly specified conditions resulted in obtaining biopeptide preparations with new and valuable properties, as compared with native lysozyme. After the enzymatic modification of lysozyme, two structural fractions were distinguished in the composition of the resulting preparations-the monomeric fraction and the peptide fraction. The modified lysozyme exhibited high surface hydrophobicity and high total antibacterial activity despite the decrease in the hydrolytic activity. Modification of lysozyme with hydrolytic enzymes, especially pepsin, resulted in preparations with very good antioxidative properties.
Topics: Muramidase; Peptide Hydrolases; Pepsin A; Hydrolysis; Dermatologic Agents
PubMed: 37687089
DOI: 10.3390/molecules28176260 -
Journal of Hazardous Materials Oct 2023Microplastics (MPs) in the environment are always colonized by microbes, which may have implications for carrying effect of pollutants and exposure risk in organisms. We...
Microplastics (MPs) in the environment are always colonized by microbes, which may have implications for carrying effect of pollutants and exposure risk in organisms. We present the crucial impacts and mechanisms of microbial colonization on the bioaccessibility and toxicity of Pb(II) loaded in disposable box-derived polypropylene (PP) and polystyrene (PS) MPs and montmorillonite (MMT) clay particles. After 45 d incubation, higher biomass measured by crystal violet staining were detected in MMT (1.23) than in PP and PS (0.400 and 0.721) indicating preferential colonization of microbes in clay particles. Microbial colonization further enhanced the sorption ability toward Pb(II), but inhibited the desorption and bioaccessibility of enriched Pb(II) in zebrafish and decreased the toxicity to gastric epithelial cells in an order of MMT > PS ≈ PP. The crucial effects were mainly because microbe-colonized substrates possessed higher oxygen functional groups and specific surface area and exhibited stronger interactions with Pb(II) and digestive component (i.e., pepsin) than pure substrates. This decreased the available soluble pepsin for complexing with sorbed Pb(II). The findings highlight the role of microbial colonization in modulating the exposure risks of artificial and natural substrate-associated pollutants and suggest that the risks of MPs may be overestimated compared to clay particles.
Topics: Animals; Bentonite; Clay; Lead; Microplastics; Pepsin A; Plastics; Zebrafish; Environmental Pollutants; Polypropylenes; Polystyrenes
PubMed: 37619279
DOI: 10.1016/j.jhazmat.2023.132350 -
Food Chemistry Jan 2024Ruminant milk is known to coagulate into structured clots during gastric digestion. This study investigated the movements of moisture and acid in skim milk clots formed...
Ruminant milk is known to coagulate into structured clots during gastric digestion. This study investigated the movements of moisture and acid in skim milk clots formed during dynamic gastric digestion and the effects of milk type (regular or calcium-rich) and the presence/absence of pepsin. We conducted hyperspectral imaging analysis and successfully modelled the moisture contents based on the spectral information using partial least squares regression. We generated prediction maps of the spatiotemporal distribution of moisture within the samples at different stages of gastric digestion. Simultaneously to acid uptake, the moisture in the milk clots tended to decrease over the digestion time; this was significantly promoted by pepsin. Moisture mapping by hyperspectral imaging demonstrated that the high and low moisture zones were centralized within the clot and at the surface respectively. A structural compaction process promoted by pepsinolysis and acidification probably contributed to the water expulsion from the clots during digestion.
Topics: Animals; Milk; Pepsin A; Hyperspectral Imaging; Stomach; Acids; Digestion
PubMed: 37586231
DOI: 10.1016/j.foodchem.2023.137094 -
Journal of Ethnopharmacology Jan 2024Chi006Eese herbal medicine Weifuchun Tablets (WFC) approved by the State Food and Drug Administration in 1982 has been widely used in treating a variety of chronic...
ETHNOPHARMACOLOGICAL RELEVANCE
Chi006Eese herbal medicine Weifuchun Tablets (WFC) approved by the State Food and Drug Administration in 1982 has been widely used in treating a variety of chronic stomach disorders including Chronic atrophic gastritis (CAG) and Gastric precancerous lesions in China clinically. This study aimed to investigate the efficacy and potential mechanism of WFC in treating Gastric intestinal metaplasia (GIM) and Gastric dysplasia (GDys).
MATERIALS AND METHODS
Rat GIM and GDys established by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) combined with hot paste, ethanol injury, and intermittent fasting were intervened by WFC. Body weight, histopathology, pH of gastric acid, pepsin activity, intestinal metaplasia index and inflammation were detected. Rat bone marrow derived macrophages (BMDMs) pretreated with WFC were stimulated by LPS. Inflammatory factors and the nuclear factor-kappa B (NF-κB) pathway were assessed. GES-1 cells pretreated by WFC were stimulated by MNNG and TNF-α, intestinal metaplasia index, the NF-κB pathway and interaction between P65 and CDX2 were detected.
RESULTS
WFC improved rat body weight, histopathology, pH value of gastric acid, activity of gastric pepsin, intestinal metaplasia (CDX2), inflammation (IL-1β, IL-6 and TNF-α), macrophage aggregation (CD68) in gastric mucosa in rat GIM and GDys. WFC inhibited inflammation (IL-1β and TNF-α) by inactivating the NF-κB pathway. WFC reduced the expression of CDX2 by inhibiting the binding of CDX2 promoter TSS upstream region with p65.
CONCLUSION
WFC blocked GIM and GDys associated with inflammation by regulating the NF-κB pathway.
Topics: Rats; Animals; NF-kappa B; Tumor Necrosis Factor-alpha; Methylnitronitrosoguanidine; Pepsin A; Inflammation; Precancerous Conditions; Hyperplasia; Stomach Neoplasms; Metaplasia; Gastric Mucosa
PubMed: 37567428
DOI: 10.1016/j.jep.2023.117020 -
Journal of Ethnopharmacology Jan 2024The traditional Chinese medicine formula Lizhong Pill (LZP) and its herbal constituents are frequently utilized in Asian (China, Saudi Arabia, India, Japan, etc.) and...
ETHNOPHARMACOLOGICAL RELEVANCE
The traditional Chinese medicine formula Lizhong Pill (LZP) and its herbal constituents are frequently utilized in Asian (China, Saudi Arabia, India, Japan, etc.) and some European (Russia, Sweden, UK, etc.) nations to treat various gastrointestinal ailments.
AIM OF THE STUDY
This study aimed to investigate the protective impact and potential mechanism of LZP against indomethacin (IND)-induced gastric mucosal injury in rats.
MATERIAL AND METHODS
Using a biochemical kit, we investigated the levels of superoxide dismutase (SOD), catalase (CAT), and glutathione S-transferase (GST) in rat serum, as well as pepsin in rat stomach tissue, using an IND-induced rat model of gastric mucosal injury. Various imaging tools, including HE staining, scanning electron microscopy (SEM), and transmission electron microscopy (TEM), were used to examine the gastric mucosa's surface morphology and ultrastructure. Furthermore, molecular docking was employed to predict the binding capacity of the primary bioactive components of LZP to the critical molecular protein targets in the IL-17 and TNF signaling pathways. At the same time, immunofluorescence was used to determine the protein expressions of CASP3, VCAM1, MAPK15, MMP3, IL-17RA, and TNFR1.
RESULTS
The present study demonstrates that LZP (3.75 and 7.50 g/kg) significantly reduces the gastric mucosal injury index induced by IND. This effect is evidenced by the improved morphology, surface, and structure of the gastric mucosa, as determined by HE, SEM, and TEM findings. Additionally, 3.75 and 7.50 g/kg LZP intervention significantly increased SOD and CAT contents and inhibited pepsin and GST activities. Molecular docking analysis revealed that the small molecular components of LZP can bind spontaneously to crucial proteins involved in the IL-17 and TNF signaling pathways, including MAPK15, MMP3, VCAM1, and CASP3. The immunofluorescence findings proved that LZP (3.75 and 7.50 g/kg) can inhibit the protein expressions of MAPK15, MMP3, VCAM1, CASP3, IL-17RA, and TNFR1.
CONCLUSIONS
Our investigation findings demonstrate that LZP can potentially ameliorate IND-induced damage to the gastric mucosa by inhibiting IL-17 and TNF signaling pathways. These results offer encouraging support for using alternative medicine to manage drug-induced gastric mucosal injury.
Topics: Rats; Animals; Receptors, Tumor Necrosis Factor, Type I; Matrix Metalloproteinase 3; Caspase 3; Pepsin A; Interleukin-17; Molecular Docking Simulation; Gastric Mucosa; Anti-Inflammatory Agents, Non-Steroidal; Stomach Diseases; Indomethacin; Superoxide Dismutase; Signal Transduction; Stomach Ulcer
PubMed: 37536648
DOI: 10.1016/j.jep.2023.116991 -
Spectrochimica Acta. Part A, Molecular... Dec 2023In this work, under simulated physiological conditions (pH = 2.2, glycine hydrochloric acid buffer solution), the interactions of cinnamic acid (CA), m-hydroxycinnamic...
In this work, under simulated physiological conditions (pH = 2.2, glycine hydrochloric acid buffer solution), the interactions of cinnamic acid (CA), m-hydroxycinnamic acid (m-CA) and p-hydroxycinnamic acid (p-CA) with pepsin were studied by fluorescence spectroscopy, ultraviolet-visible absorption spectroscopy, circular dichroism (CD) spectroscopy, Fourier transform infrared spectroscopy (FTIR), molecular docking and molecular dynamic simulation (MD). The spectrogram results showed that these three kinds of CA had a strong ability to quench the intrinsic fluorescence of pepsin, and the quenching effects were obvious with the increase of concentration of these three kinds of molecules. The quenching mechanism of CA, m-CA and p-CA on the fluorescence of pepsin was static quenching. In addition, a stable complex was formed between three kinds of CA with pepsin. Thermodynamic data and docking information suggested that three kinds of CA combine with pepsin were mainly driven by electrostatic force and hydrogen bond. The binding constant and the number of binding sites were determined. The interaction of CA, m-CA and p-CA with pepsin was spontaneous, and accompanied by non-radiative energy transfer. The results from CD, FTIR, UV-Vis and synchronous fluorescence spectra measurements manifested that the secondary structure of pepsin was changed by the binding of three kinds of CA. The β-sheet of pepsin increased after the interaction with three kinds of CA. The assay results of pepsin activity showed that three kinds of CA led to a decrease in pepsin activity within the investigated concentrations. Molecular docking investigation revealed the formation of polar hydrogen bonds as well as hydrophobic interactions between three kinds of CA with pepsin, and the ligand within the binding pocket of pepsin. MD results implied the formation of a stable complex between three kinds of CA and pepsin. The research suggested that cinnamic acid and its derivatives could be a potential effect on the structure and properties of digestive enzyme.
Topics: Molecular Docking Simulation; Pepsin A; Spectrophotometry, Ultraviolet; Binding Sites; Spectrometry, Fluorescence; Thermodynamics; Protein Binding; Circular Dichroism
PubMed: 37517266
DOI: 10.1016/j.saa.2023.123169 -
Environmental Pollution (Barking, Essex... Oct 2023Human ingestion of microplastics (MPs) is common and inevitable due to the widespread contamination of food items, but implications on the gastric digestion of food...
Human ingestion of microplastics (MPs) is common and inevitable due to the widespread contamination of food items, but implications on the gastric digestion of food proteins are still unknown. In this study, the interactions between pepsin and polystyrene (PS) MPs were evaluated by investigating enzyme activity and conformation in a simulated human gastric environment in the presence or absence of PS MPs. The impact on food digestion was also assessed by monitoring the kinetics of protein hydrolysis through static in vitro gastric digestion of cow's milk contaminated with PS. The binding of pepsin to PS showed that the surface chemistry of MPs dictates binding affinity. The key contributor to pepsin adsorption seems to be π-π interactions between the aromatic residues and the PS phenyl rings. During quick exposure (10 min) of pepsin to increasing concentrations (222, 2219, 22188 particles/mL) of 10 μm PS (PS10) and 100 μm PS (PS100), total enzymatic activities were not affected remarkably. However, upon prolonged exposure at 1 and 2 h, preferential binding of pepsin to the small, low zeta-potential PS caused structural changes in the protein which led to a significant reduction of its activity. Digestion of cow's milk mixed with PS10 resulted in transient accumulation of larger peptides (10-35 kDa) and reduced bioavailability of short peptides (2-9 kDa) in the gastric phase. This, however, was only observed at extremely high PS10 concentration (0.3 mg/mL or 5.46E+05 particles/mL). The digestion of milk peptides, bound preferentially over pepsin within the hard corona on the PS10 surface, was delayed up to 15 min in comparison to bulk protein digestion. Intact caseins, otherwise rapidly digested, remained bound to PS10 in the hard corona for up to 15 min. This work presents valuable insights regarding the interaction of MPs, food proteins, and pepsin, and their dynamics during gastric digestion.
Topics: Humans; Milk Proteins; Pepsin A; Microplastics; Polystyrenes; Plastics; Peptides; Caseins; Allergens; Digestion
PubMed: 37516294
DOI: 10.1016/j.envpol.2023.122282 -
International Journal of Biological... Sep 2023Fish skin gelatin is an important functional product used in food, medicine and other industries. However, the structure and function of gelatins extracted with...
Fish skin gelatin is an important functional product used in food, medicine and other industries. However, the structure and function of gelatins extracted with different methods differ significantly, thus limiting its production and application. This study used dry-salting, wet-salting, pepsin, acid and heat methods to extract gelatins from the skins of tilapia, grass carp and sea perch. Then, their structural characteristics (micro- and ultra-structure, amyloid-like fibril, etc.) and functional properties (viscosity, emulsifying performance, antioxidant abilities, etc.) were analyzed, and interaction between gelatin components were also explored. According to the results, the gelatins extracted with dry-salting and wet-salting methods had better reticular structure, larger fiber length/height, and higher viscosity properties, emulsifying and antioxidant capacity. The gelatin extracted by applying heat has the highest gel strength, and the gelatin extracted using pepsin had better thermal stability, water absorption capacity, and fat absorption capacity. Further analysis of component interaction showed that 11 types of collagens detected in the gelatins might promote the conversion of collagen to gelatin through self-assembly ability. The co-assembly of different types of collagens enhanced the properties of gelatin. Decorin had a positive effect on gelatin network structure, but Metallopeptidase inhibited the formation of network structure. Different methods can produce personalized gelatin products according to specific needs. The mining of component interaction would reveal the mechanism of gelatin formation and promote the development of gelatin synthetic biology.
Topics: Animals; Gelatin; Antioxidants; Pepsin A; Chemical Phenomena; Collagen
PubMed: 37479198
DOI: 10.1016/j.ijbiomac.2023.125813