Nanoparticles Loaded with a Carotenoid-Rich Extract from Cantaloupe Melon Improved Hepatic Retinol Levels in a Diet-Induced Obesity Preclinical Model.

The study evaluated the effect of the carotenoid-rich extract from cantaloupe melon (CE) nanoencapsulated in porcine gelatin (EPG) on hepatic retinol concentration and liver damage scores in Wistar rats with obesity induced by high glycemic index and high glycemic load diet (HGLI diet). For 17 days, animals were fed the HGLI diet. They were divided into three groups and treated for 10 days [HGLI diet + water, HGLI diet + CE (12.5 mg/kg), and HGLI diet + EPG (50 mg/kg)]. The groups were evaluated for dietary intake, retinol, weight variation, hematological parameters, fasting glucose, lipid profile, hepatic retinol concentration, AST/ALT ratio, FIB-4 (Fibrosis-4 Index for Liver Fibrosis), and APRI (AST to Platelet Ratio Index) scores to evaluate the effects on the liver. Animals treated with EPG showed a lower dietary intake (p < 0.05). No significant weight change was detected in the evaluated groups (p > 0.05). The EPG-treated group had significantly higher concentrations (p < 0.05) of hepatic retinol [266 (45) µg/g] than the untreated group [186 (23.8) µg/g] and the one treated with CE [175 (8.08) µg/g]. Liver damage assessment scores did not show significant differences, but the lowest means were observed in the group treated with EPG. The nanoencapsulation of the extract rich in beta-carotene promoted reduced food consumption and increased hepatic retinol without causing significant changes in liver damage scores. Thus, EPG is a candidate for future clinical studies to evaluate the beneficial effects of treating diseases involving vitamin A deficiencies.

Hydrolyzed Proteins and Vegetable Peptides: Anti-Inflammatory Mechanisms in Obesity and Potential Therapeutic Targets.

Chronic low-grade inflammation is present in overweight and obesity, causing changes in several metabolic pathways. It impairs systemic functioning and positively feeds back the accumulation of more adipose tissue. Studies with hydrolyzed proteins and plant peptides have demonstrated a potential anti-inflammatory and immunomodulatory effect of these peptides. However, it is challenging and necessary to explore the mechanism of action of such molecules because understanding their effects depends on their structural characterizations. Furthermore, the structure might also give insights into safety, efficacy and efficiency, with a view of a possible health application. Thus, the present narrative review aimed to discuss the mechanisms of action of hydrolyzed proteins and plant peptides as anti-inflammatory agents in obesity. Keywords and related terms were inserted into databases for the search. Based on the studies evaluated, these biomolecules act by different pathways, favoring the reduction of inflammatory cytokines and adipokines and the polarization of macrophages to the M2 phenotype. Finally, as a future perspective, bioinformatics is suggested as a tool to help understand and better use these molecules considering their applicability in pre-clinical and clinical studies.

Antibacterial action mechanisms and mode of trypsin inhibitors: a systematic review.

This systematic review (SR) aimed to gather studies describing the antibacterial action mechanisms and mode of trypsin inhibitors. The review protocol was registered (PROSPERO: CRD42020189069). Original articles resulting from studies in animal models, in bacterial culture, and using cells that describe antibacterial action of trypsin inhibitor-type peptides or proteins were selected in PubMed, Science Direct, Scopus, Web of Science, BVS, and EMBASE. The methodological quality assessment was performed using the PRISMA and OHAT tool. 2382 articles were retrieved, 17 of which were eligible. Four studies demonstrated the action mechanism directly on the bacterial membrane, and the fifth study on endogenous proteases extracted from the bacteria themselves. The antibacterial action mode was presented in the other studies, which can generate bacteriostatic or bactericidal effects without describing the mechanisms. This study generated information to enable new preclinical or clinical studies with molecules contributing to public health.

Can polyphenols improve the gut health status in pre-clinical study with diet-induced obesity?: A protocol for systematic review and/or meta-analysis.

INTRODUCTION: Obesity is characterized as a low-grade inflammation that impairs physiological functions, including intestinal functioning and gut microbiota balance. Dietary polyphenols can be a strategy for obesity management, collaborating to preserve or recover gut health through antioxidant and anti-inflammatory actions, as well as modulators of the microbiota. This study describes a systematic review protocol to elucidate effects of polyphenols on intestinal health of pre-clinical models with diet-induced obesity. AIM: Our aim is to evaluate evidence about polyphenols' effects in the gut microbiota composition and diversity, parameters of the physical and molecular status of the gut barrier in obese models, additionally, understand the possible involved mechanisms. METHODOLOGY: A protocol was developed and published on PROSPERO (Registration No: CRD42021262445). Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols is used to outline the protocol. The articles will be selected according to the PICOS strategy (population, interventions, control, outcome, and study design) in the following databases: PubMed, Science Direct, Scopus, Web of Science, and EMBASE. Experimental studies performed on rats and mice with a control group that describes treatment with polyphenols (from food matrix or crude extracts or isolated compounds) at any frequency, time, and dose will be included. Two reviewers will, independently, select the papers, extract data, and evaluate the data quality. The Systematic Review Center for Laboratory Animal Experimentation (SYRCLE) tool will be used to assess the risk of bias. EXPECTED RESULTS: Results will be showed through of native synthesis and, if possible, a metanalysis will be conducted. The review produced with this protocol can show the scientific evidence level about polyphenols' effects in intestinal health in obesity status.

What are the digestion and absorption models used to reproduce gastrointestinal protein processes?: A protocol for systematic review.

BACKGROUND: Animal, cell, and in vitro studies have been applied to simulate the human gastrointestinal tract (GIT) and evaluate the behavior of biomolecules. Understanding the peptides and/or proteins stability when exposed to these physiological conditions of the GIT can assist in the application of these molecules in the treatment of diseases such as obesity. This study describes a protocol of systematic reviews to analyze the methodologies that mimic the digestive and absorptive processes of peptides and/or proteins. METHODS: The protocol follows the guidelines described by Preferred Reporting Items for Systematic Reviews and Meta-Analyzes Protocols (PRISMA-P). The search strategies will be applied in the electronic databases PubMed, ScienceDirect, Scopus, Web of Science, Evidence portal, Virtual Health Library, and EMBASE. The intervention group will be formed by in vivo, in cells, and in vitro (gastrointestinal simulating fluids) studies of digestion and absorption of peptides and/or proteins presenting a schedule, duration, frequency, dosages administered, concentration, and temperature, and the control group consisting in studies without peptides and/or proteins. The selection of studies, data extraction, and assessment of the risk of bias will be carried out independently by 2 reviewers. For animal studies, the risk of bias will be assessed by the instrument of the Systematic Review Center for Experimentation with Laboratory Animals (SYRCLE) and the Office of Health Assessment and Translation (OHAT) tool will be used to assess the risk of bias in cell studies. RESULTS: This protocol contemplates the development of 2 systematic reviews and will assist the scientific community in identifying methods related to the digestive and absorptive processes of peptides and/or proteins. CONCLUSION: Both systematic reviews resulting from this protocol will provide subsidies for the construction of research related to the clinical application of bioactive peptides and/or proteins. In this context, they will make it possible to understand the gastrointestinal processes during administering these molecules, as the gastrointestinal environment can affect its functionality. Therefore, validating the effectiveness of these protocols is important, as it mimics in vitro biological conditions, reducing the use of animals, being consistent with the reduction, refine and replace program.

What are the mechanisms of action of anti-inflammatory agents in adipose tissue?: A protocol for systematic review and meta-analysis.

BACKGROUND: Obesity is a disease characterized by the abnormal accumulation of adipose tissue in the body, triggering a chronic subclinical state of inflammation. Bioactive compounds, given their anti-inflammatory properties, are a safe and promising alternative in controlling the inflammatory condition of obesity. This study describes a systematic review protocol aiming to analyze the anti-inflammatory molecules mechanisms and compounds action on adipocytes. METHODS: Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) will outline the protocol and PRISMA to the systematic review. The databases used for research will be PubMed, Science Direct, Scopus, Web of Science, BVS, and EMBASE. Experimental studies performed on rats and mice with a control group that describes treatment with anti-inflammatory agents (drugs, nutraceuticals, bio active compounds, among others) at any frequency, time, and dose will be included. Three independent reviewers will select studies and extract data. The evaluation of the methodological quality of each research will be performed using the SYRCLE tool. If at least 2 studies show clinical and/or methodological and/or statistical homogeneity, a meta-analysis will be performed, using the RevMan Analyzes statistical package in Review Manager v.5.3. RESULTS: In this study, we hope to find a considerable number of articles presenting mechanisms involved in the action of anti-inflammatory molecules and compounds on adipocytes. CONCLUSION: The systematic review produced from this protocol will present evidence on the mechanisms involved in the action of anti-inflammatory molecules and compounds in adipocytes. It will also contribute to developing new research and new insights about anti-inflammatory therapies with a future application view. RECORD OF SYSTEMATIC REVIEW: This review was registered with the International Register of Prospective Systematic Reviews on May 18, 2020 (registration: CRD42020182897). Available at: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020182897.

Structural insights and molecular dynamics into the inhibitory mechanism of a Kunitz-type trypsin inhibitor from Tamarindus indica L.

Trypsin inhibitors from tamarind seed have been studied in vitro and in preclinical studies for the treatment of obesity, its complications and associated comorbidities. It is still necessary to fully understand the structure and behaviour of these molecules. We purifed this inhibitor, sequenced de novo by MALDI-TOF/TOF, performed its homology modelling, and assessed the interaction with the trypsin enzyme through molecular dynamics (MD) simulation under physiological conditions. We identified additional 75 amino acid residues, reaching approximately 72% of total coverage. The four best conformations of the best homology modelling were submitted to the MD. The conformation n°287 was selected considering the RMSD analysis and interaction energy (-301.0128 kcal.mol-1). Residues Ile (54), Pro (57), Arg (59), Arg (63), and Glu (78) of pTTI presented the highest interactions with trypsin, and arginine residues were mainly involved in its binding mechanism. The results favour bioprospecting of this protein for pharmaceutical health applications.

Safety and bioactive potential of nanoparticles containing Cantaloupe melon (Cucumis melo L.) carotenoids in an experimental model of chronic inflammation.

The safety and bioactive potential of crude carotenoid extract from Cantaloupe melon nanoencapsulated in porcine gelatin (EPG) were evaluated in a chronic inflammatory experimental model. Animals were fed a high glycemic index and high glycemic load (HGLI) diet for 17 weeks and treated for ten days with 1) HGLI diet, 2) standard diet, 3) HGLI diet + crude carotenoid extract (CE) (12.5 mg/kg), and 4) HGLI diet + EPG (50 mg/kg). General toxicity signals were investigated, considering body weight, food intake, hematological, biochemical parameters, relative weight, morphology, and histopathology of organs. The biochemical parameters indicated the low toxicity of EPG. Acute hepatitis was observed in animals' livers, but CE and EPG groups presented improved tissue appearance. Chronic enteritis was observed in animals, with villi and intestinal glands preservation in the EPG group. The results suggest the safety and the bioactive effect of EPG, possibly related to its anti-inflammatory potential.

Effect of carotenoid encapsulation on antioxidant activities: A protocol for systematic review.

BACKGROUND: Carotenoids play essential roles in human health, such as antioxidant activity, and therefore can decrease free radicals oxidation action, preventing numerous diseases. However, these compounds have an unstable nature, turning them susceptible to adverse conditions in food processing and storage. Thereby the search for alternatives that maintain and enhance carotenoid antioxidant function, such as encapsulation, has grown. The objective of this study was to establish a systematic review protocol to evaluate the effect of different encapsulation techniques on the antioxidant action of carotenoids, evaluating which one is the best and safest, and their role in enhancing the antioxidant activity. METHODS: This protocol was guided by the preferred reporting items for protocols for systematic reviews and meta-analyzes. The databases to be searched are PubMed, EMBASE, Scopus, ScienceDirect, and Web of Science. Experimental studies conducted in rats and mice (in vivo) of both sexes and ages, evaluating the use of encapsulated and crude carotenoids will be included in the systematic review. The characteristics of the studies, the experimental model, and the main results will be described, and the risk of bias assessment will be evaluated. Three independent reviewers will proceed with the selection of studies, data extraction, and methodological quality assessment. A narrative synthesis will be made for the included studies. Besides, if sufficient qualitative data is available, a meta-analysis will be conducted. I2 statistics will be used to assess heterogeneity. RESULTS: This protocol will guide the production of a systematic review that can determine the effect of different encapsulation techniques and encapsulating agents on the antioxidant action of carotenoids. Thus, it will enable the determination of the best encapsulation techniques to promote the preservation and increase of the antioxidant activity, contributing to future research that may reproduce the best carotenoid encapsulation technique in an animal model. CONCLUSION: The systematic review to be produced from this protocol will provide support for the construction of research that evaluates the effect of encapsulation on the antioxidant function of carotenoids and its possible application as a nutraceutical, considering that this functionality is directly associated with health promotion. RECORD OF SYSTEMATIC REVIEW: This review was recorded in the International Register of Prospective Systematic Reviews on January 22, 2020 (registration: CRD42020142065). Available at: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020142065.

Adipocytes and intestinal epithelium dysfunctions linking obesity to inflammation induced by high glycemic index pellet-diet in Wistar rats.

We investigated the inflammatory effect of a pellet-diet with high glycemic index and load (HGLI) on the histological organization of adipocytes, intestinal epithelium, and fat in liver and pancreas in adult male Wistar rats. Two groups (n=10) received for 17 weeks: (1) HGLI diet or (2) Standard diet (Labina®). Histological analyses of adipose tissue, jejunum, liver, and pancreas were performed. Stereology analysis, visceral adiposity index, gene expression, and immunohistochemistry of tumor necrosis factor-α (TNF-α) in visceral adipose tissue and plasma TNF-α were also assessed. The HGLI diet-induced hypertrophy of adipocytes with adipocyte volume density equal to 97.0%, cross-sectional area of adipocytes equivalent to 1387 µm² and a total volume of adipocytes of 6.97 cm³ an elevation of 8%, 25%, and 58%, respectively. Furthermore, the HGLI diet increased liver and pancreatic fat deposition, altered and inflamed the intestinal epithelia, and increased TNF-α gene expression (P=0.014) with a positive immunostaining in visceral adipose tissue and high plasma TNF-α in comparison with standard diet. The results suggest that this diet was able to generate changes commonly caused to solid diets with high fat or fructose-rich beverages. To the best of our knowledge, this is the first report in the literature concerning the properties of low-cost, sucrose-rich pellet-diet presenting high glycemic index and high glycemic load efficient on the development of obesity complications in Wistar rats that were subjected to diet-induced obesity. Therefore, the HGLI pellet-diet may be considered an effective tool to be used by the scientific community in experimental research.

Gastroprotective and antielastase effects of protein inhibitors from Erythrina velutina seeds in an experimental ulcer model.

Trypsin and chymotrypsin inhibitors from Erythrina velutina seeds have been previously isolated by our group. In previous studies using a sepsis model, we demonstrated the antitumor and anti-inflammatory action of these compounds. This study aimed to evaluate the gastroprotective and antielastase effects of protein inhibitors from E. velutina seeds in an experimental stress-induced ulcer model. Two protein isolates from E. velutina seeds, with antitrypsin (PIAT) and antichymotrypsin (PIAQ) activities, were tested. Both protein isolates showed a high affinity and inhibitory effect against human neutrophil elastase, with 84% and 85% inhibition, respectively. Gastric ulcer was induced using ethanol (99%) in 6 groups of animals (female Wistar rats, n = 6). Before ulcer induction, these animals were treated for 5 days with one of the following: (1) PIAT (0.2 mg·kg-1), (2) PIAT (0.4 mg·kg-1), (3) PIAQ (0.035 mg·kg-1), (4) ranitidine hydrochloride (50 mg·kg-1), (5) saline solution (0.9%), or (6) no intervention (sham). Both PIAT and PIAQ protected gastric mucosa, preventing hemorrhagic lesions, edema, and mucus loss. No histologic toxic effects of PIAT or PIAQ were seen in liver and pancreatic cells. Our results show that protein isolates from E. velutina seeds have potential gastroprotective effects, placing these compounds as natural candidates for gastric ulcer prevention.