Challenges in simulating the human gut for understanding the role of the microbiota in obesity

2017 ◽  
Vol 8 (1) ◽  
pp. 31-53 ◽  
Author(s):  
M. Aguirre ◽  
K. Venema
Keyword(s):  
Potential Role ◽  
Human Gut ◽  
Colonic Fermentation ◽  
Physiological Relevance ◽  
In Vitro Simulation ◽  
In Vitro Systems ◽  
Specific Standard ◽  
Obese Subjects

There is an elevated incidence of cases of obesity worldwide. Therefore, the development of strategies to tackle this condition is of vital importance. This review focuses on the necessity of optimising in vitro systems to model human colonic fermentation in obese subjects. This may allow to increase the resolution and the physiological relevance of the information obtained from this type of studies when evaluating the potential role that the human gut microbiota plays in obesity. In light of the parameters that are currently used for the in vitro simulation of the human gut (which are mostly based on information derived from healthy subjects) and the possible difference with an obese condition, we propose to revise and improve specific standard operating procedures.

scholarly journals Bioaminergic Responses in an In Vitro System Studying Human Gut Microbiota–Kiwifruit Interactions

2020 ◽  
Vol 8 (10) ◽  
pp. 1582
Author(s):  
Shanthi Parkar ◽  
Carel Jobsis ◽  
Tania Trower ◽  
Janine Cooney ◽  
Duncan Hedderley ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Gene Expression Analysis ◽  
Serotonin Synthesis ◽  
Gastrointestinal Digestion ◽  
Human Gut ◽  
Colonic Fermentation ◽  
In Vitro System ◽  
Physiological Relevance ◽  
Intestinal Functions

Whole kiwifruit (‘Hayward’ and ‘Zesy002’) were examined for their bioaminergic potential after being subjected to in vitro gastrointestinal digestion and colonic fermentation. Controls included the prebiotic inulin and water, a carbohydrate-free vehicle. The dopamine precursor l-dihydroxyphenylalanine (L-DOPA) and the serotonin precursor 5-hydroxytryptophan were increased in the kiwifruit gastrointestinal digesta (‘Hayward’ > ‘Zesy002’) in comparison to the water digesta. Fermentation of the digesta with human fecal bacteria for 18 h modulated the concentrations of bioamine metabolites. The most notable were the significant increases in L-DOPA (‘Zesy002’ > ‘Hayward’) and γ-aminobutyric acid (GABA) (‘Hayward’ > ‘Zesy002’). Kiwifruit increased Bifidobacterium spp. and Veillonellaceae (correlating with L-DOPA increase), and Lachnospira spp. (correlating with GABA). The digesta and fermenta were incubated with Caco-2 cells for 3 h followed by gene expression analysis. Effects were seen on genes related to serotonin synthesis/re-uptake/conversion to melatonin, gut tight junction, inflammation and circadian rhythm with different digesta and fermenta from the four treatments. These indicate potential effects of the substrates and the microbially generated organic acid and bioamine metabolites on intestinal functions that have physiological relevance. Further studies are required to confirm the potential bioaminergic effects of gut microbiota–kiwifruit interactions.

scholarly journals Preservation of Human Gut Microbiota Inoculums for In Vitro Fermentations Studies

Fermentation ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 14
Author(s):  
Nelson Mota de Carvalho ◽  
Diana Luazi Oliveira ◽  
Mayra Anton Dib Saleh ◽  
Manuela Pintado ◽  
Ana Raquel Madureira
Keyword(s):  
Gut Microbiota ◽  
Metabolic Profile ◽  
Bacterial Count ◽  
Glycerol Solution ◽  
Metabolic Profiles ◽  
Human Gut ◽  
Colonic Fermentation ◽  
In Vitro Fermentation ◽  
Fecal Samples

The use of fecal inoculums for in vitro fermentation models requires a viable gut microbiota, capable of fermenting the unabsorbed nutrients. Fresh samples from human donors are used; however, the availability of fresh fecal inoculum and its inherent variability is often a problem. This study aimed to optimize a method of preserving pooled human fecal samples for in vitro fermentation studies. Different conditions and times of storage at −20 °C were tested. In vitro fermentation experiments were carried out for both fresh and frozen inoculums, and the metabolic profile compared. In comparison with the fresh, the inoculum frozen in a PBS and 30% glycerol solution, had a significantly lower (p < 0.05) bacterial count (<1 log CFU/mL). However, no significant differences (p < 0.05) were found between the metabolic profiles after 48 h. Hence, a PBS and 30% glycerol solution can be used to maintain the gut microbiota viability during storage at −20 °C for at least 3 months, without interfering with the normal course of colonic fermentation.

scholarly journals Specificity of the HIV-1 Protease on Substrates Representing the Cleavage Site in the Proximal Zinc-Finger of HIV-1 Nucleocapsid Protein

Viruses ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1092
Author(s):  
János András Mótyán ◽  
Márió Miczi ◽  
Stephen Oroszlan ◽  
József Tőzsér
Keyword(s):  
Amino Acid ◽  
Zinc Finger ◽  
Cleavage Site ◽  
Potential Role ◽  
Binding Mode ◽  
Interaction Energies ◽  
Vitro Assay ◽  
Hiv 1

To explore the sequence context-dependent nature of the human immunodeficiency virus type 1 (HIV-1) protease’s specificity and to provide a rationale for viral mutagenesis to study the potential role of the nucleocapsid (NC) processing in HIV-1 replication, synthetic oligopeptide substrates representing the wild-type and modified versions of the proximal cleavage site of HIV-1 NC were assayed as substrates of the HIV-1 protease (PR). The S1′ substrate binding site of HIV-1 PR was studied by an in vitro assay using KIVKCF↓NCGK decapeptides having amino acid substitutions of N17 residue of the cleavage site of the first zinc-finger domain, and in silico calculations were also performed to investigate amino acid preferences of S1′ site. Second site substitutions have also been designed to produce “revertant” substrates and convert a non-hydrolysable sequence (having glycine in place of N17) to a substrate. The specificity constants obtained for peptides containing non-charged P1′ substitutions correlated well with the residue volume, while the correlation with the calculated interaction energies showed the importance of hydrophobicity: interaction energies with polar residues were related to substantially lower specificity constants. Cleavable “revertants” showed one residue shift of cleavage position due to an alternative productive binding mode, and surprisingly, a double cleavage of a substrate was also observed. The results revealed the importance of alternative binding possibilities of substrates into the HIV-1 PR. The introduction of the “revertant” mutations into infectious virus clones may provide further insights into the potential role of NC processing in the early phase of the viral life-cycle.

scholarly journals Cortistatin Is Not a Somatostatin Analogue but Stimulates Prolactin Release and Inhibits GH and ACTH in a Gender-Dependent Fashion: Potential Role of Ghrelin

Endocrinology ◽  
2011 ◽  
Vol 152 (12) ◽  
pp. 4800-4812 ◽  
Author(s):  
José Córdoba-Chacón ◽  
Manuel D. Gahete ◽  
Ana I. Pozo-Salas ◽  
Antonio J. Martínez-Fuentes ◽  
Luis de Lecea ◽  
...  
Keyword(s):  
Metabolic Phenotype ◽  
Somatostatin Analogue ◽  
Growth Hormone Secretagogue Receptor ◽  
Growth Hormone Secretagogue ◽  
Ancestral Gene ◽  
Ghrelin Receptor ◽  
Physiological Relevance

Cortistatin (CST) and somatostatin (SST) evolve from a common ancestral gene and share remarkable structural, pharmacological, and functional homologies. Although CST has been considered as a natural SST-analogue acting through their shared receptors (SST receptors 1–5), emerging evidence indicates that these peptides might in fact exert unique roles via selective receptors [e.g. CST, not SST, binds ghrelin receptor growth hormone secretagogue receptor type 1a (GHS-R1a)]. To determine whether the role of endogenous CST is different from SST, we characterized the endocrine-metabolic phenotype of male/female CST null mice (cort−/−) at hypothalamic-pituitary-systemic (pancreas-stomach-adrenal-liver) levels. Also, CST effects on hormone expression/secretion were evaluated in primary pituitary cell cultures from male/female mice and female primates (baboons). Specifically, CST exerted an unexpected stimulatory role on prolactin (PRL) secretion, because both male/female cort−/− mice had reduced PRL levels, and CST treatment (in vivo and in vitro) increased PRL secretion, which could be blocked by a GHS-R1a antagonist in vitro and likely relates to the decreased success of female cort−/− in first-litter pup care at weaning. In contrast, CST inhibited GH and adrenocorticotropin-hormone axes in a gender-dependent fashion. In addition, a rise in acylated ghrelin levels was observed in female cort−/− mice, which were associated with an increase in stomach ghrelin/ghrelin O-acyl transferase expression. Finally, CST deficit uncovered a gender-dependent role of this peptide in the regulation of glucose-insulin homeostasis, because male, but not female, cort−/− mice developed insulin resistance. The fact that these actions are not mimicked by SST and are strongly gender dependent offers new grounds to investigate the hitherto underestimated physiological relevance of CST in the regulation of physiological/metabolic processes.

scholarly journals High Expression of GSDMC Is Associated with Poor Survival in Kidney Clear Cell Cancer

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Yun-Qian Cui ◽  
Fei Meng ◽  
Wen-Li Zhan ◽  
Zhou-Tong Dai ◽  
Xinghua Liao
Keyword(s):  
Potential Role ◽  
Clear Cell ◽  
Cell Cancer ◽  
Progression Free Survival ◽  
Renal Clear Cell Carcinoma ◽  
High Expression ◽  
Poor Survival ◽  
Free Survival

This study is aimed at exploring the potential role of GSDMC in kidney renal clear cell carcinoma (KIRC). We analyzed the expression of GSDMC in 33 types of cancers in TCGA database. The results showed that the expression of GSDMC was upregulated in most cancers. We found a significant association between high expression of GSDMC and shortened patient overall survival, progression-free survival, and disease-specific survival. In vitro experiments have shown that the expression of GSDMC was significantly elevated in KIRC cell lines. Moreover, decreased expression of GSDMC was significantly associated with decreased cell proliferation. In summary, we believe that this study provides valuable data supporting future clinical treatment.

The Role of Microbiology in Models of Dental Caries: Reaction Paper

1995 ◽  
Vol 9 (3) ◽  
pp. 255-269 ◽  
Author(s):  
G.H. Bowden
Keyword(s):  
Process Selection ◽  
Advantages And Disadvantages ◽  
Test Models ◽  
Plaque Development ◽  
In Vitro Systems ◽  
Selection Of

Models of the caries process have made significant contributions toward defining the roles of bacteria in caries. Microbiologists use a variety of in vitro systems to model aspects of the caries process. Also, in situ models in humans provide information on the microbiology of caries in vivo. These models do not involve the entire process leading to natural caries; consequently, the results from such studies are used to deduce the roles of bacteria in natural caries. Therefore, they can be described as Inferential Caries Models. In contrast, animal models and some clinical trials in humans involve natural caries and can be described as Complete Caries Models. Furthermore, these models are used in two distinct ways. They can be used as Exploratory Models to explore different aspects of the caries process, or as Test Models to determine the effects of anticaries agents. This dichotomy in approach to the use of caries models results in modification of the models to suit a particular role. For example, if we consider Exploratory Models, the in situ appliance in humans is superior to others for analyzing the microbiology of plaque development and demineralization in vivo. The chemostat and biofilm models are excellent for exploring factors influencing bacterial interactions. Both models can also be used as Test Models. The in situ model has been used to test the effects of fluoride on the microflora and demineralization, while the chemostat and biofilm models allow for the testing of antibacterial agents. Each model has its advantages and disadvantages and role in analysis of the caries process. Selection of the model depends on the scientific question posed and the limitations imposed by the conditions available for the study.

scholarly journals Ozone Therapy as Adjuvant for Cancer Treatment: Is Further Research Warranted?

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Bernardino Clavo ◽  
Norberto Santana-Rodríguez ◽  
Pedro Llontop ◽  
Dominga Gutiérrez ◽  
Gerardo Suárez ◽  
...  
Keyword(s):  
Cancer Treatment ◽  
Immune Modulation ◽  
Animal Studies ◽  
Potential Role ◽  
Randomized Clinical Trials ◽  
Tumor Hypoxia ◽  
Tumor Resection ◽  
Ozone Therapy

Introduction. This article provides an overview of the potential use of ozone as an adjuvant during cancer treatment.Methods. We summarize the findings of the most relevant publications focused on this goal, and we include our related clinical experience.Results. Over several decades, prestigious journals have publishedin vitrostudies on the capacity of ozone to induce direct damage on tumor cells and, as well, to enhance the effects of radiotherapy and chemotherapy. Indirect effects have been demonstrated in animal models: immune modulation by ozone alone and sensitizing effect of radiotherapy by concurrent ozone administration. The effects of ozone in modifying hemoglobin dissociation curve, 2,3-diphosphoglycerate levels, locoregional blood flow, and tumor hypoxia provide additional support for potential beneficial effects during cancer treatment. Unfortunately, only a few clinical studies are available. Finally, we describe some works and our experience supporting the potential role of local ozone therapy in treating delayed healing after tumor resection, to avoid delays in commencing radiotherapy and chemotherapy.Conclusions.In vitroand animal studies, as well as isolated clinical reports, suggest the potential role of ozone as an adjuvant during radiotherapy and/or chemotherapy. However, further research, such as randomized clinical trials, is required to demonstrate its potential usefulness as an adjuvant therapeutic tool.

scholarly journals Potential Role of the Chemokine Macrophage Inflammatory Protein 1α in Human and Experimental Schistosomiasis

2005 ◽  
Vol 73 (4) ◽  
pp. 2515-2523 ◽  
Author(s):  
Adriano L. S. Souza ◽  
Ester Roffê ◽  
Vanessa Pinho ◽  
Danielle G. Souza ◽  
Adriana F. Silva ◽  
...  
Keyword(s):  
Potential Role ◽  
Severe Disease ◽  
Experimental Studies ◽  
Interleukin 4 ◽  
Enzyme Linked Immunosorbent Assay ◽  
Inflammatory Protein ◽  
Macrophage Inflammatory Protein ◽  
Deficient Mice

ABSTRACT In human schistosomiasis, the concentrations of the chemokine macrophage inflammatory protein 1α (MIP-1α/CCL3) is greater in the plasma of patients with clinical hepatosplenic disease. The objective of the present study was to confirm the ability of CCL3 to detect severe disease in patients classified by ultrasonography (US) and to evaluate the potential role of CCL3 in Schistosoma mansoni-infected mice. CCL3 was measured by enzyme-linked immunosorbent assay in the plasma of S. mansoni-infected patients. CCL3-deficient mice were infected with 25 cercariae, and various inflammatory and infectious indices were evaluated. The concentration of CCL3 was higher in the plasma of S. mansoni-infected than noninfected patients. Moreover, CCL3 was greater in those with US-defined hepatosplenic than with the intestinal form of the disease. In CCL3-deficient mice, the size of the granuloma and the liver eosinophil peroxidase activity and collagen content were diminished compared to wild-type mice. In CCL3-deficient mice, the worm burden after 14 weeks of infection, but not after 9 weeks, was consistently smaller. The in vitro response of mesenteric lymph node cells to antigen stimulation was characterized by lower levels of interleukin-4 (IL-4) and IL-10. CCL3 is a marker of disease severity in infected humans, and experimental studies in mice suggest that CCL3 may be a causative factor in the development of severe schistosomiasis.

scholarly journals Role for the Related Poly(ADP-Ribose) Polymerases Tankyrase 1 and 2 at Human Telomeres

2002 ◽  
Vol 22 (1) ◽  
pp. 332-342 ◽  
Author(s):  
Brandoch D. Cook ◽  
Jasmin N. Dynek ◽  
William Chang ◽  
Grigoriy Shostak ◽  
Susan Smith
Keyword(s):  
Potential Role ◽  
Telomere Maintenance ◽  
Telomeric Dna ◽  
Continuous Growth ◽  
Telomere Elongation ◽  
Bona Fide ◽  
Tankyrase 1 ◽  
Growth Of Tumor

ABSTRACT Telomere maintenance is essential for the continuous growth of tumor cells. In most human tumors telomeres are maintained by telomerase, a specialized reverse transcriptase. Tankyrase 1, a human telomeric poly(ADP-ribose) polymerase (PARP), positively regulates telomere length through its interaction with TRF1, a telomeric DNA-binding protein. Tankyrase 1 ADP-ribosylates TRF1, inhibiting its binding to telomeric DNA. Overexpression of tankyrase 1 in the nucleus promotes telomere elongation, suggesting that tankyrase 1 regulates access of telomerase to the telomeric complex. The recent identification of a closely related homolog of tankyrase 1, tankyrase 2, opens the possibility for a second PARP at telomeres. We therefore sought to establish the role of tankyrase 1 at telomeres and to determine if tankyrase 2 might have a telomeric function. We show that endogenous tankyrase 1 is a component of the human telomeric complex. We demonstrate that telomere elongation by tankyrase 1 requires the catalytic activity of the PARP domain and does not occur in telomerase-negative primary human cells. To investigate a potential role for tankyrase 2 at telomeres, recombinant tankyrase 2 was subjected to an in vitro PARP assay. Tankyrase 2 poly(ADP-ribosyl)ated itself and TRF1. Overexpression of tankyrase 2 in the nucleus released endogenous TRF1 from telomeres. These findings establish tankyrase 2 as a bona fide PARP, with itself and TRF1 as acceptors of ADP-ribosylation, and suggest the possibility of a role for tankyrase 2 at telomeres.

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