Pitfalls and novel experimental approaches to optimize microbial interventions for chemotherapy-induced gastrointestinal mucositis

PURPOSE OF REVIEW: There is a growing number of studies implicating gut dysbiosis in mucositis development. However, few studies have shed light on the causal relationship limiting translational potential. Here, we detail the key supportive evidence for microbial involvement, candidate mechanisms by which the microbiome may contribute to mucositis and emerging approaches to model host-microbe interactions with clinical relevance and translational potential. RECENT FINDINGS: Synthesis of existing clinical data demonstrate that modulating the microbiome drastically alters the development and severity of mucositis, providing a strong rationale for its involvement. Review of the literature revealed potential microbiome-dependent mechanisms of mucosal injury including altered drug metabolism, bile acid synthesis and regulation of the intestinal barrier. Current studies are limited in their mechanistic insight due to cross-sectional and would benefit from longitudinal analyses and baseline phenotyping. SUMMARY: The causative role of the microbiome in mucositis development remains unclear. Future studies must adopt comprehensive microbial analyses with functional assessment, and utilize emerging ex-vivo models to interrogate host-microbe interactions in mucositis

Alkyl-Glycerol Rescues Plasmalogen Levels and Pathology of Ether-Phospholipid Deficient Mice

A deficiency of plasmalogens, caused by impaired peroxisomal metabolism affects normal development and multiple organs in adulthood. Treatment options aimed at restoring plasmalogen levels may be relevant for the therapy of peroxisomal and non-peroxisomal disorders. In this study we determined the in vivo efficacy of an alkyl glycerol (AG), namely, 1-O-octadecyl-rac-glycerol, as a therapeutic agent for defects in plasmalogen synthesis. To achieve this, Pex7 knockout mice, a mouse model for Rhizomelic Chondrodysplasia Punctata type 1 characterized by the absence of plasmalogens, and WT mice were fed a control diet or a diet containing 2% alkyl-glycerol. Plasmalogen levels were measured in target organs and the biochemical data were correlated with the histological analysis of affected organs. Plasmalogen levels in all peripheral tissues of Pex7 KO mice fed the AG diet for 2 months normalized to the levels of AG fed WT mice. In nervous tissues of Pex7 KO mice fed the AG-diet, plasmalogen levels were significantly increased compared to control fed KO mice. Histological analysis of target organs revealed that the AG-diet was able to stop the progression of the pathology in testis, adipose tissue and the Harderian gland. Interestingly, the latter tissues are characterized by the presence of lipid droplets which were absent or reduced in size and number when ether-phospholipids are lacking, but which can be restored with the AAG treatment. Furthermore, nerve conduction in peripheral nerves was improved. When given prior to the occurrence of major pathological changes, the AG-diet prevented or ameliorated the pathology observed in Pex7 KO mice depending on the degree of plasmalogen restoration. This study provides evidence of the beneficial effects of treating a plasmalogen deficiency with alkyl-glycerol

Functional characterization of Arabidopsis thaliana transthyretin-like protein

<p>Abstract</p> <p>Background</p> <p><it>Arabidopsis thaliana </it>transthyretin-like (TTL) protein is a potential substrate in the brassinosteroid signalling cascade, having a role that moderates plant growth. Moreover, sequence homology revealed two sequence domains similar to 2-oxo-4-hydroxy-4-carboxy-5-ureidoimidazoline (OHCU) decarboxylase (N-terminal domain) and 5-hydroxyisourate (5-HIU) hydrolase (C-terminal domain). TTL is a member of the transthyretin-related protein family (TRP), which comprises a number of proteins with sequence homology to transthyretin (TTR) and the characteristic C-terminal sequence motif Tyr-Arg-Gly-Ser. TRPs are single domain proteins that form tetrameric structures with 5-HIU hydrolase activity. Experimental evidence is fundamental for knowing if TTL is a tetrameric protein, formed by the association of the 5-HIU hydrolase domains and, in this case, if the structural arrangement allows for OHCU decarboxylase activity. This work reports about the biochemical and functional characterization of TTL.</p> <p>Results</p> <p>The TTL gene was cloned and the protein expressed and purified for biochemical and functional characterization. The results show that TTL is composed of four subunits, with a moderately elongated shape. We also found evidence for 5-HIU hydrolase and OHCU decarboxylase activities <it>in vitro</it>, in the full-length protein.</p> <p>Conclusions</p> <p>The <it>Arabidopsis thaliana </it>transthyretin-like (TTL) protein is a tetrameric bifunctional enzyme, since it has 5-HIU hydrolase and OHCU decarboxylase activities, which were simultaneously observed <it>in vitro</it>.</p

Prophylactic Treatment with Vitamins C and B2 for Methotrexate-Induced Gastrointestinal Mucositis

Mucositis is a common side-effect of chemotherapy treatment, inducing alterations in the composition of the gut microbiota. Redox active compounds, such as vitamins B2 and C, have been shown to reduce inflammation and enhance the growth of anaerobic bacteria in the gut. We therefore aimed to (1) validate the ability of these compounds to promote bacterial cell growth in vitro, and (2) determine their prophylactic efficacy in a rat model of methotrexate (MTX)-induced mucositis. Bacterial growth curves were performed to assess the growth kinetics of bacteria exposed to Vitamins C and B2 (0.5 mM). Male wistar rats (150-200 g) received vitamins B2 (12 mg/day) and C (50 mg/day) via daily oral gavage (from day -1 to day 10). MTX (45 mg/Kg) was administrated via I.V. injection (N = 4-8/group) on day 0. Body weight, water/food consumption and diarrhea were assessed daily. Blood and faecal samples were collected longitudinally to assess citrulline levels (mucositis biomarker) and gut microbiota composition. Vitamins C/B2 enhanced the in vitro growth of anaerobic bacteria Blautia coccoides and Roseburia intestinalis. Contrarily to vitamin B2, in vivo administration of Vitamin C significantly attenuated clinical symptoms of mucositis. Despite their influence on the composition of the gut microbiota, both vitamins did not modulate the course of MTX-induced mucositis, as accessed by plasma citrulline. Vitamins B2 and C enhanced anaerobic bacterial growth in vitro, however their ability to mitigate MTX-induced mucositis was limited

Extracellular enolase of Candida albicans is involved in colonization of mammalian intestinal epithelium

Enolase is secreted by C. albicans and is present in its biofilms although its extracellular function is unknown. Here we show that extracellular enolase mediates the colonization of small intestine mucosa by C. albicans. Assays using intestinal mucosa disks show that C. albicans adhesion is inhibited, in a dose dependent mode, either by pretreatment of intestinal epithelium mucosa disks with recombinant C. albicans enolase (70% at 0.5 mg/ml enolase) or by pretreatment of C. albicans yeasts with anti-enolase antibodies (48% with 20 µg antiserum). Also using flow cytometry, immunoblots of conditioned media and confocal microscopy we demonstrate that enolase is present in biofilms and that the extracellular enolase is not an artifact due to cell lysis, but must represent functional secretion of a stable form. This is the first direct evidence that C. albicans extracellular enolase mediates colonization on its primary translocation site. Also, because enolase is encoded by a single locus in C. albicans, its dual role peptide, as glycolytic enzyme and extracellular peptide, is a remarkable example of gene sharing in fungi

Enterotype May Drive the Dietary-Associated Cardiometabolic Risk Factors

Analyses of typical bacterial clusters in humans named enterotypes may facilitate understanding the host differences in the cardiometabolic profile. It stills unknown whether the three previously described enterotypes were present in populations living below the equator. We examined how the identification of enterotypes could be useful to explain the dietary associations with cardiometabolic risk factors in Brazilian subjects. In this cross-sectional study, a convenience sample of 268 adults (54.2% women) reported their dietary habits and had clinical and biological samples collected. In this study, we analyzed biochemical data and metagenomics of fecal microbiota (16SrRNA sequencing, V4 region). Continuous variables were compared using ANOVA, and categorical variables using chi-square test. Vsearch clustered the operational taxonomic units, and Silva Database provided the taxonomic signatures. Spearman coefficient was used to verify the correlation between bacteria abundances within each enterotype. One hundred subjects were classified as omnivore, 102 lacto-ovo-vegetarians, and 66 strict vegetarians. We found the same structure as the three previously described enterotypes: 111 participants were assigned to Bacteroides, 55 to Prevotella, and 102 to Ruminococcaceae enterotype. The Prevotella cluster contained higher amount of strict vegetarians individuals than the other enterotypes (40.0 vs. 20.7 and 20.6, p = 0.04). Subjects in this enterotype had a similar anthropometric profile but a lower mean LDL-c concentration than the Bacteroides enterotype (96 +/- 23 vs. 109 +/- 32 mg/dL, p = 0.04). We observed significant correlations between bacterial abundances and cardiometabolic risk factors, but coefficients differed depending on the enterotype. In Prevotella enterotype, Eubacterium ventriosum (r BMI = -0.33, p = 0.03, and r HDL-c = 0.33, p = 0.04), Akkermansia (r 2h glucose = -0.35, p = 0.02), Roseburia (r BMI = -0.36, p = 0.02 and r waist = -0.36, p = 0.02), and Faecalibacterium (r insulin = -0.35, p = 0.02) abundances were associated to better cardiometabolic profile. The three enterotypes previously described are present in Brazilians, supporting that those bacterial clusters are not population-specific. Diet-independent lower LDL-c levels in subjects from Prevotella than in other enterotypes suggest that a protective bacterial cluster in the former should be driving this association. Enterotypes seem to be useful to understand the impact of daily diet exposure on cardiometabolic risk factors. Prospective studies are needed to confirm their utility for predicting phenotypes in humans.FAPESPUniv Sao Paulo, Sch Publ Hlth, Dept Epidemiol, Sao Paulo, BrazilFundacao Oswaldo Cruz, Rene Rachou Res Ctr, Belo Horizonte, MG, BrazilUniv Fed Sao Paulo, Dept Prevent Med, Sao Paulo, BrazilUniv Sao Paulo, Sch Med, Heart Inst Incor, Lab Genet & Mol Cardiol, Sao Paulo, BrazilUniv Fed Sao Paulo, Dept Prevent Med, Sao Paulo, BrazilFAPESP: 2012/12626-9FAPESP: 2012/03880-9Web of Scienc

Antibiotic-induced disruption of the microbiome exacerbates chemotherapy-induced diarrhoea and can be mitigated with autologous faecal microbiota transplantation

BACKGROUND: Chemotherapy is well documented to disrupt the gut microbiome, leading to poor treatment outcomes and a heightened risk of adverse toxicity. Although strong associations exist between its composition and gastrointestinal toxicity, its causal contribution remains unclear. Our inability to move beyond association has limited the development and implementation of microbial-based therapeutics in chemotherapy adjuncts with no clear rationale of how and when to deliver them. METHODS/RESULTS: Here, we investigate the impact of augmenting the gut microbiome on gastrointestinal toxicity caused by the chemotherapeutic agent, methotrexate (MTX). Faecal microbiome transplantation (FMT) delivered after MTX had no appreciable impact on gastrointestinal toxicity. In contrast, disruption of the microbiome with antibiotics administered before chemotherapy exacerbated gastrointestinal toxicity, impairing mucosal recovery (P < 0.0001) whilst increasing diarrhoea severity (P = 0.0007) and treatment-related mortality (P = 0.0045). Importantly, these detrimental effects were reversed when the microbiome was restored using autologous FMT (P = 0.03), a phenomenon dictated by the uptake and subsequent expansion of Muribaculaceae. CONCLUSIONS: These are the first data to show that clinically impactful symptoms of gastrointestinal toxicity are dictated by the microbiome and provide a clear rationale for how and when to target the microbiome to mitigate the acute and chronic complications caused by disruption of the gastrointestinal microenvironment. Translation of this new knowledge should focus on stabilising and strengthening the gut microbiome before chemotherapy and developing new microbial approaches to accelerate recovery of the mucosa. By controlling the depth and duration of mucosal injury, secondary consequences of gastrointestinal toxicity may be avoided.Hannah R.Wardill, Stijn A.R.van der Aa, Ana R.da Silva Ferreira, Rick Havinga, Wim J.E.Tissing, Hermie J.M.Harmse

Validação de marcadores moleculares do tipo microssatélites em bananeira.

A banana é um dos produtos alimentares mais produzidos no mundo atualmente, com mais de 130 países produtores. Torna-se muito importante pois é grande geradora de fonte e renda empregando milhões de pessoas em todo o território nacional, principalmente no Nordeste do pais, onde a maioria dos produtores são de baixa renda. Dentre os fatores limitantes da cultura está o cultivo de variedades pouco resistentes a pragas e doenças; e uma estratégia para a solução deste problema é a do programa de melhoramento na busca de variedades mais produtivas e resistentes. Sendo assim os marcadores moleculares torna-se uma ferramenta acessória aos programas de melhoramento. Dentre os marcadores moleculares mais utilizados nos estudos genéticos em bananeira, os marcadores microssatélites, destacam-se por serem altamente informativos, multialélicos e por apresentarem alta reprodutibilidade. Este trabalho objetivou a validação de marcadores moleculares microssatélites EST e BAC ? SSRs para auxílio ao programa de mapeamento genético da bananeira, em diplóides de bananeira contrastantes para resistência a Sigatoka amarela e negra.PDF. 033

Identification of drought-responsive genes in roots of upland rice (Oryza sativa L)

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