Para melhor compreender o papel dos micro-organismos nas doenças da cavidade bucal, é necessário inicialmente avaliar a diversidade microbiana naturalmente existente em indivíduos saudáveis, além de sua distribuição espacial na cavidade bucal. Muitos estudos são conduzidos elucidando o papel do biofilme e das bactérias na saúde bucal, porém poucas pesquisas focaram na atuação das leveduras. Neste sentido, o objetivo do presente trabalho foi avaliar a diversidade e distribuição de leveduras do gênero Candida na microbiota bucal de indivíduos saudáveis. Foram coletadas amostras da boca pacientes adultos saudáveis. Foram obtidas amostras de 9 diferentes habitats da boca: bochechas direita e esquerda, assoalho da boca, palato, língua dorsal, língua ventral, dente molar, vestíbulo labial e saliva. Foram avaliados 100 pacientes com uma média de 28 dentes. Quarenta e nove indivíduos apresentaram leveduras na sua microbiota bucal. Candida albicans foi o micro-organismo mais prevalente (49%), seguido de Candida krusei, Candida parapsilosis, Meyerozyma guilliermondii (C. guilliermondii), Candida glabrata, Candida tropicalis e Candida dubliniensis. A associação das leveduras encontradas e os habitats bucais sugeriu que comunidades leveduriformes podem distinguir-se entre os diferentes tecidos da cavidade bucal. A língua (dorsal e ventral) apresentou colonização específica, caracterizada pelas espécies C. tropicalis e C. dubliniensis. De forma semelhante, a microbiota dos habitats revestidos por mucosa foi análoga. A microbiota da língua e dos tecidos duros assemelhou-se entre si em menor intensidade. Estes resultados introduzem a dimensão espacial desta diversidade microbiana que vem sendo estudada, complementando as informações obtidas nos estudos do microbioma humano. / To better understand the role of microorganisms in the diseases of the oral cavity, first it is necessary to evaluate the natural microbial diversity in healthy individuals, as well as their spatial distribution in the oral cavity. Many studies are conducted elucidating the role of biofilms and bacteria in oral health, but few research has focused on the yeast’s performance. In this sense, the objective of this study was to evaluate the diversity and distribution of Candida species in the oral microbiota of healthy individuals. Samples were colleted from the mouth of healthy adults. Samples of 9 different mouth habitats were obtained: right and left cheeks, floor of the mouth, palate, dorsal tongue, ventral tongue, molar tooth, labial vestibule and saliva. We evaluated 100 patients with an average of 28 teeth. Forty-nine subjects had yeasts in their oral microbiota. Candida albicans was the most prevalent microorganism (49%), followed by Candida krusei, Candida parapsilosis, Meyerozyma guilliermondii (C. guilliermondii), Candida glabrata, Candida tropicalis and Candida dubliniensis. The association found between the yeasts and oral habitats suggested that communities can be distinguished by the different tissues of the oral cavity. The tongue (dorsal and ventral) presented specific colonization, characterized by the species C. tropicalis, and C. dubliniensis. Similarly, the microbiota of the mucous habitats was similar. The microbiota of the tongue and hard tissue resembled each other in a lesser degree. These results introduce the spatial dimension of the microbial diversity that has been studied, complementing the information obtained in the human microbiome research.

Para melhor compreender o papel dos micro-organismos nas doenças da cavidade bucal, é necessário inicialmente avaliar a diversidade microbiana naturalmente existente em indivíduos saudáveis, além de sua distribuição espacial na cavidade bucal. Muitos estudos são conduzidos elucidando o papel do biofilme e das bactérias na saúde bucal, porém poucas pesquisas focaram na atuação das leveduras. Neste sentido, o objetivo do presente trabalho foi avaliar a diversidade e distribuição de leveduras do gênero Candida na microbiota bucal de indivíduos saudáveis. Foram coletadas amostras da boca pacientes adultos saudáveis. Foram obtidas amostras de 9 diferentes habitats da boca: bochechas direita e esquerda, assoalho da boca, palato, língua dorsal, língua ventral, dente molar, vestíbulo labial e saliva. Foram avaliados 100 pacientes com uma média de 28 dentes. Quarenta e nove indivíduos apresentaram leveduras na sua microbiota bucal. Candida albicans foi o micro-organismo mais prevalente (49%), seguido de Candida krusei, Candida parapsilosis, Meyerozyma guilliermondii (C. guilliermondii), Candida glabrata, Candida tropicalis e Candida dubliniensis. A associação das leveduras encontradas e os habitats bucais sugeriu que comunidades leveduriformes podem distinguir-se entre os diferentes tecidos da cavidade bucal. A língua (dorsal e ventral) apresentou colonização específica, caracterizada pelas espécies C. tropicalis e C. dubliniensis. De forma semelhante, a microbiota dos habitats revestidos por mucosa foi análoga. A microbiota da língua e dos tecidos duros assemelhou-se entre si em menor intensidade. Estes resultados introduzem a dimensão espacial desta diversidade microbiana que vem sendo estudada, complementando as informações obtidas nos estudos do microbioma humano. / To better understand the role of microorganisms in the diseases of the oral cavity, first it is necessary to evaluate the natural microbial diversity in healthy individuals, as well as their spatial distribution in the oral cavity. Many studies are conducted elucidating the role of biofilms and bacteria in oral health, but few research has focused on the yeast’s performance. In this sense, the objective of this study was to evaluate the diversity and distribution of Candida species in the oral microbiota of healthy individuals. Samples were colleted from the mouth of healthy adults. Samples of 9 different mouth habitats were obtained: right and left cheeks, floor of the mouth, palate, dorsal tongue, ventral tongue, molar tooth, labial vestibule and saliva. We evaluated 100 patients with an average of 28 teeth. Forty-nine subjects had yeasts in their oral microbiota. Candida albicans was the most prevalent microorganism (49%), followed by Candida krusei, Candida parapsilosis, Meyerozyma guilliermondii (C. guilliermondii), Candida glabrata, Candida tropicalis and Candida dubliniensis. The association found between the yeasts and oral habitats suggested that communities can be distinguished by the different tissues of the oral cavity. The tongue (dorsal and ventral) presented specific colonization, characterized by the species C. tropicalis, and C. dubliniensis. Similarly, the microbiota of the mucous habitats was similar. The microbiota of the tongue and hard tissue resembled each other in a lesser degree. These results introduce the spatial dimension of the microbial diversity that has been studied, complementing the information obtained in the human microbiome research.

Background: Recent research showing how dietary interventions substantially influence the potential presence of widespread and stable bacterial core phyla in the human colon has garnered a considerable amount of attention. Because the human gut can play a major role in host health, there is currently some interest in observing how diet influences human gut microbial composition and how changes in diet affect the potential for gut microbiota to transform mercury. This study aims to discover how different kinds of diet affect the nature and magnitude of microbial Hg transformations in the human gut environment. Methods: Fecal samples have been collected from 5 human male individuals at University of Ottawa and stored at -80ºC for further investigation. Using high throughput DNA amplicon sequencing targeting the 16s rRNA V4 region, we investigated the microbial community structure of the gut in 5 healthy male. Mercury biotransformations in the pooled fecal sample have been carried out using stable isotopes of mercury (198HgCl2 and Me199HgCl) and analysis was conducted by using inductively coupled plasma mass spectrometry (ICP-MS). Results and conclusions: We were not able to detect any significant Hg methylation or MeHg demethylation. We suspect this is due to Enterobacteria dominating the microbial community structure after 96h; Although Enterobacteria are part of the typical microbiota of a healthy individual, they do not possess genes required for Hg methylation. As such, our microbial data support our chemical analyses. We were not able to identify whether a change in diet affected Hg transformations in the human gut environment.

La obesidad es un problema de salud a nivel mundial que incrementa el riesgo de sufrir un amplio rango de comorbilidades, incluyendo la diabetes tipo II y las enfermedades cardiovasculares. Debido a estos motivos, es necesario encontrar estrategias para reducir la obesidad y sus co-morbilidades y que puedan ser implementadas en los sistemas de salud públicos. El objetivo general de la tesis ha sido avanzar en el conocimiento de la influencia de la composición y funciones de la microbiota intestinal y su genoma (microbioma) en la obesidad y alteraciones metabólicas asociadas e identificar bacterias intestinales que, junto a cambios en la dieta, puedan contribuir a establecer estrategias de intervención más eficaces para controlar estos desórdenes. El capítulo primero de la tesis se centra en el estudio de la seguridad y habilidad para metabolizar distintas fuentes de fibra de Bacteroides uniformis CECT 7771. Para ello, hemos llevado a cabo la secuenciación del genoma y el análisis del transcriptoma de la bacteria en respuesta a diferentes fuentes de carbono. Se ha observado que B. uniformis CECT7771 es capaz de fermentar todos los sustratos evaluados y crecer más rápido en presencia de aquellas fuentes de carbono de estructura más sencilla (salvado de trigo rico en arabinoxilanos (AXOS) y glucosa). Además, B.uniformis CECT 7771 posee la capacidad de degradar los O-glicanos de la mucina y producir butirato y disminuir la producción de ácidos grasos de cadena larga y proteínas transportadoras de acilo (ACPs), implicados en la síntesis de lipopolisacárido (LPS) bacteriano causante de endotoxemia. Cuando crece en presencia de pectina, B. uniformis CECT 7771 incrementa la producción y secreción de GABA, lo cual podría tener un impacto en el eje intestino-cerebro. B. uniformis CECT 7771 no ha mostrado signos de toxicidad o patogenicidad tras el análisis exhaustivo de los genes codificados en su genoma, ni tras su administración por vía oral en un modelo de toxicidad sub-crónica en ratas. En este modelo, la bacteria produce un perfil de citocinas anti-inflamatorio comparado con el grupo placebo y muestra un efecto dosis-dependiente en la disminución de los valores de la alanina aminotransferasa (ALT), sugiriendo un efecto hepato-protector. En el segundo capítulo de la tesis se ha llevado a cabo un estudio de intervención en humanos con sobrepeso y síndrome metabólico en el que se evaluó, en un primer lugar, los efectos de la suplementación dietética con fibras enriquecidas en AXOS y ácidos grasos poliinsaturados (PUFAs) durante 4 semanas en la composición de la microbiota intestinal y en los parámetros bioquímicos. Los resultados demuestran que la ingesta de AXOS modifica la microbiota, ejerciendo un efecto bifidogénico y un aumento de especies bacterianas productoras de butirato, aunque no hemos visto una mejora en los parámetros bioquímicos analizados. En el caso de la intervención con PUFAs, no hemos detectado cambios en la composición de la microbiota ni en los parámetros bioquímicos evaluados. En segundo lugar, hemos llevado a cabo un estudio multi-ómico en un subgrupo de sujetos de la intervención con AXOS a fin de profundizar en los efectos de este tipo de fibra. El análisis metagenómico nos ha permitido identificar cambios en la configuración de la microbiota intestinal, incluyendo un aumento de Ruminococcus gnavus y Prevotella spp. así como una disminución de Parabacteroides, Paraprevotella y Rikenella. También hemos detectado un incremento de metagenes implicados en la producción de tetrahidrofolato y derivados del ácido fólico, los cuales llevan a cabo una función protectora frente a la hiperhomocisteinemia; la vitamina K2, implicada en la correcta absorción del calcio; y el GABA, cuya baja concentración en el organismo se asocia a estados de ansiedad y desbalance energético y que favorece la secreción de insulina y regula los niveles de ceramidas en plasma. / L'obesitat és un problema de salut a nivell mundial que incrementa el risc de patir un ampli rang de comorbilitats, incloent la diabetis tipus II i les malalties cardiovasculars. A causa d'estos motius, és necessari trobar estratègies per a reduir l'obesitat i les seues co-morbiditats i que puguen ser implementades en els sistemes de salut públics. L'objectiu general de la tesi ha sigut avançar en el coneixement de la influència de la composició i funcions de la microbiota intestinal i el seu genoma (microbioma) en l'obesitat i alteracions metabóliques associades i identificar bacteris intestinals que, junt amb canvis en la dieta, puguen contribuir a establir estratègies d'intervenció més eficaços per a controlar estos desordes. El capítol primer de la tesi es centra en l'estudi de la seguretat i habilitat per a metabolitzar distintes fonts de fibra de Bacteroides uniformis CECT 7771. Per a això, hem dut a terme la seqüenciació del genoma i l'anàlisi del transcriptoma del bacteri en resposta a diferents fonts de carboni. S'ha observat que B. uniformis CECT7771 és capaç de fermentar tots els substrats avaluats i créixer més ràpid en presència d'aquelles fonts de carboni d'estructura més senzilla (segó de blat ric en arabinoxilans (AXOS) i glucosa). A més, B.uniformis CECT 7771 posseïx la capacitat de degradar els O-glicans de la mucina i produir butirat i disminuir la producció d'àcids grassos de cadena llarga i proteïnes transportadores d'acil (ACPs), implicades en la síntesi de lipopolisacárid (LPS) bacterià causant d'endotoxemia. Quan creix en presència de pectina, B. uniformis CECT 7771 incrementa la producció i secreció de GABA, la qual cosa podria tindre un impacte en l'eix intestí-cervell. B. uniformis CECT 7771 no ha mostrat signes de toxicitat o patogenicidad després de l'anàlisi exhaustiva dels gens codificats en el seu genoma, ni després de la seua administració per via oral en un model de toxicitat subcrònica en rates. En este model, el bacteri produïx un perfil de citoquines antiinflamatori comparat amb el grup placebo i mostra un efecte dosi- dependent en la disminució dels valors de l'alanino aminotransferasa (ALT) , suggerint un efecte hepato-protector. En el segon capítol de la tesi s'ha dut a terme un estudi d'intervenció en humans amb sobrecàrrega i síndrome metabòlica en què es va avaluar, en un primer lloc, els efectes de la suplementació dietètica amb fibres enriquides en AXOS i àcids grassos poliinsaturats (PUFAs) durant 4 setmanes en la composició de la microbiota intestinal i en els paràmetres bioquímics (mesures antropomètriques, metabolisme de glucosa, perfil lipídic, marcadors d'inflamació, etc.). Els resultats demostren que la ingesta d'AXOS modifica la microbiota, exercint un efecte bifidogénic i un augment d'espècies bacterianes productores de butirat, encara que no hem vist una millora en els paràmetres bioquímics analitzats. En el cas de la intervenció amb PUFAs, no hem detectat canvis en la composició de la microbiota ni en els paràmetres bioquímics avaluats. En segon lloc, hem dut a terme un estudi multi-ómic en un subgrup de subjectes de la intervenció amb AXOS a fi d'aprofundir en els efectes d'este tipus de fibra. L'anàlisi metagenómic ens ha permés identificar canvis en la configuració de la microbiota intestinal, incloent un augment de Ruminococcus gnavus i Prevotella spp. així com una disminució de Parabacteroides, Paraprevotella i Rikenella. També hem detectat un increment de metagens implicats en la producció de tetrahidrofolat i derivats de l'àcid fòlic, els quals duen a terme una funció protectora enfront de l'hiperhomocisteinemia; la vitamina K2, implicada en la correcta absorció del calci; i el GABA, la baixa concentració del qual en l'organisme s'associa a estats d'ansietat i desbalanç energètic i que afavorix la secreció d'insulina i regula els nivells de ceramides en plasma. L'anàlisi conjunta / Obesity is a global health problem that increases the risk of suffering a wide range of comorbidities, including type II diabetes and cardiovascular diseases. Due to these reasons, it is necessary to find strategies to reduce obesity and its co-morbidities that can be implemented in public health systems. The general objective of the thesis has been to advance in the knowledge of the influence of the composition and functions of the intestinal microbiota and its genome (microbiome) in obesity and associated metabolic alterations and to identify intestinal bacteria that, together with changes in the diet, can help to establish more effective intervention strategies to control these disorders. The first chapter of the thesis focuses on the study of the safety and ability to metabolize different fiber sources of Bacteroides uniformis CECT 7771. For this, we have carried out the genome sequencing and the transcriptome analysis of the bacteria in response to different carbon sources. It has been observed that B. uniformis CECT7771 is able to ferment all evaluated substrates and grow faster in the presence of those carbon sources of simpler structure (wheat bran rich in arabinoxylans (AXOS) and glucose). In addition, B.uniformis CECT 7771 has the ability to degrade the mucin O-glycans, produce butyrate and decrease the production of long chain fatty acids and acyl transport proteins (ACPs), involved in the synthesis of bacterial lipopolysaccharide (LPS) that causes endotoxemia. When grown in the presence of pectin, B. uniformis CECT 7771 increases the production and secretion of GABA, which could have an impact on the gut-brain axis. B. uniformis CECT 7771 has shown no signs of toxicity or pathogenicity after exhaustive analysis of the genes encoded in its genome, or after oral administration in a model of sub-chronic toxicity in rats. In this model, the bacterium produces an anti-inflammatory cytokine profile compared to the placebo group and shows a dose-dependent effect in the decrease of the alanine aminotransferase (ALT) values, suggesting a hepato-protective effect. In the second chapter of the thesis it was done an intervention study in humans with overweight and metabolic syndrome to evaluate at first the effects of dietary supplementation with fibers enriched in AXOS and polyunsaturated fatty acids (PUFAs) during 4 weeks in the composition of the intestinal microbiota and in the biochemical parameters. The results show that the intake of AXOS modifies the microbiota, exerting a bifidogenic effect and an increase of bacterial species that produce butyrate, although we have not seen an improvement in the biochemical parameters analyzed. In the case of the intervention with PUFAs, we have not detected changes in the composition of the microbiota or in the biochemical parameters evaluated. Secondly, we have carried out a multi-omic study in a subgroup of subjects of the intervention with AXOS in order to delve into the effects of this type of fiber. The metagenomic analysis has allowed us to identify changes in the configuration of the intestinal microbiota, including an increase in Ruminococcus gnavus and Prevotella spp. as well as a decrease of Parabacteroides, Paraprevotella and Rikenella. We have also detected an increase in metagenes involved in the production of tetrahydrofolate and folic acid derivatives, which perform a protective function against hyperhomocysteinemia; vitamin K2, involved in the correct absorption of calcium; and GABA, whose low concentration in the body is associated with states of anxiety and energy imbalance and that favors the secretion of insulin and regulates plasma ceramide levels. The joint analysis of the metagenome and the metabolome has allowed us to establish positive correlations between the abundance of Prevotella and the concentrations of short chain fatty acids and succinate, as well as between increases of Eubacterium rectale and reductions in methylamines, which could be involved in t / Gómez Del Pulgar Villanueva, EM. (2018). Identificación de componentes de la microbiota intestinal potencialmente beneficiosos frente a la obesidad [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/114770 / TESIS

Thesis advisor: Babak Momeni / Rothia mucilaginosa is a gram-positive bacterium that is found in the human oral microbiota. Under normal circumstances, it exhibits a commensal relationship with humans. However, in immunocompromised patients and those with medical implants, these bacteria can pose a serious health risk. In this thesis I outline experiments performed to reveal more about the normal role of R. mucilaginosa within the oral microbiota in the hopes of better understanding its transition to virulence. R. mucilaginosa was grown alongside several of its major co-inhabitants in the oral microbiota in pairwise fashion on solid growth media to search for signs of interspecies interactions. After initial screening, those pairs that showed consistent patterns of interaction were selected for further analysis via fluorescence microscopy. A consistent interaction pattern was confirmed between R. mucilaginosa and Streptococcus gordonii. Interactions were also noted between Corynebacterium durum and R. mucilaginosa as well as between Corynebacterium durum and Neisseria elongata. / Thesis (BS) — Boston College, 2018. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: Scholar of the College. / Discipline: Biology.

Dietary composition can impact colonization and composition of gut microbiota. The first aim of this dissertation was to evaluate the effect of dietary Se deprivation, sex and, aging on taxonomic composition of gut microbiota in mice. We have previously shown that long-term dietary Se deprivation promotes health span deteriorate including type-2 diabetes like symptoms in later state Terc-/- mice carrying humanized telomeres. In the present study, the data suggested that the dietary Se deprivation and aging significantly and comparably altered the gut microflora composition. The ratio of Firmicutes/Bacteroidetes was decreased by dietary Se deprivation or aging in both sexes. Abundance of selective gut bacteria genus was associated with dietary Se status and aging as evidenced by heat map and principal coordinate analyses. Moreover, the abundance of Akkermensia muciniphila, a bacterium in association with obesity, differed by Se-deprivation, aging and sex. Taken together, changes in gut microbiota composition by dietary Se deprivation may accelerate mouse aging in a sex-specific manner. The second aim of this dissertation was to investigate the effects and underlying mechanism of fecal fermentation of non-digestible fibers isolated from common beans on adipocyte differentiation and fat accumulation to elucidate the cellular mechanisms. Treatment of 3T3-L1 murine preadipocytes with fermented product resulted in a reduction of triglyceride accumulation in a dose- and time-dependent manner. The fermentation product exhibited antiipogenic effects through suppression of the adipogenesis-associated key transcription factors or activators peroxisome proliferator-activated receptor gamma (Ppar gamma), CCAAT enhancer-bind protein alpha (C/ebp alpha) and fatty acid binding protein 4 (Fabp4). Moreover, the mRNA expression lipolytic genes including peroxisome proliferator-activated receptor delta (Ppar delta) and mitochondrial uncoupling protein 2 (Ucp2) were induced by the fermentation products of non-digestible fiber isolated from common beans counteract adipogenesis through regulation of key targets.Altogether, optimizing gut microbiota by nutritionally adequate level of dietary Se and non-digestible fiber appears to represent a promising strategy to control or prevent early onset of aging and age-related metabolic diseases.

<p> Understanding the mechanisms of microbiome assembly during host development is crucial for successful modulation of the gut microbiome to improve host health and growth. Detailed characterization of the swine gut microbiome through meta-analysis allows us to understand the dynamics of microbial community succession, as well as the transient and natural variations between timepoints and animals. A total of 3,313 fecal samples from over 349 pigs covering 60 time points (from birth to market age) from 14 publications were included in the meta-analysis in Chapter 2. Alpha diversity continuously increased during early stages of animal growth and increased at a slower rate in the following stages. Random forest regression identified 30 OTUs as potential microbiota biomarkers for modeling swine gut microbiome development and the external validation suggested the generalization and benchmarking role of our models in application to future microbiome studies conducted in suckling and weaning pigs. In Chapter 3, a total of 924 fecal samples from 44 newborn piglets over 21 time points (day one of age until 41 days of age) were collected every two days and community composition, assembly, and succession was determined using the V4 region of the 16S rRNA gene. Alpha diversity continuously increased during the suckling stage, yet there was no significant increase in alpha diversity during days post-weaning. Post-weaning in-feed antibiotics consistently decreased the microbial diversity and changed the community structure in both low birth weight (LBW) and normal birth weight (NBW) piglets. Delayed gut microbial community maturation was observed in LBW piglets on post-weaning days compared with NBW. Heterogeneity of the gut microbial community between piglets linearly decreased over time, as revealed by the within-time Bray-Curtis dissimilarities. Intra-individual variance both in community structure and genus abundance indicates the importance of repeated measurements for reliable observations. Dirichlet multinomial mixtures analysis supported an age-dependent microbiome developmental pattern and identified microbial taxa that are age-discriminatory. Our study addresses ecological processes shaping the swine gut microbiome between piglets with contrasting birth weights and receiving post-weaning antibiotics. Persistent gut microbiota immaturity in LBW piglets suggests that efforts to accelerate microbial community succession might improve LBW piglet growth performance and disease resistance. </p>

Maternal obesity is a key predictor of childhood obesity. It has been shown to cause changes in maternal adaptation to pregnancy that result in an adverse in utero environment, inducing increased risk of obesity and metabolic disease in the offspring. Perturbation of gut microbiota over the course of pregnancy has been implicated in maternal metabolic adaptations. We investigated how high-fat (HF) diet-induced obesity before and during pregnancy affects gut microbiota and maternal intestinal barrier function, and whether altered maternal gut adaptations to pregnancy influence placental development. Microbiota of HF mice was modified by diet, and further modulated by pregnancy. Changes in mucin-degrading and short chain fatty acid (SCFA) producing bacteria were found in microbiota from HF pregnant mice. SCFA receptor, GPR41, expression was reduced in the duodenum and jejunum of HF dams. Intestinal barrier function was impaired in HF pregnancies as indicated by increased paracellular intestinal permeability measured by passage of FITC-Dextran and increased concentration of bacterial lipopolysaccharide in the maternal serum, observations that were consistent with reduced gene expression of tight junction proteins in the small intestine of HF dams. Diet-induced maternal obesity altered gene expression of inflammatory and immune cell marker genes in different gut sections. However, no change in TNF and IL-6 in maternal serum suggested that HF diet-induced obesity was not associated with systemic maternal inflammation. Female placenta from HF pregnancies were smaller in size, as calculated by measuring the cross sectional area of the placenta, which may be regulated by increased apoptosis. Augmented placental inflammation was not observed in HF placentas. Changes in maternal intestinal adaptations appear to be modified by diet-induced obesity before and during pregnancy, in a manner that reduced maternal barrier function and increased intestinal immune cell markers but these changes appeared not be associated with placental pro-inflammatory status. / Thesis / Master of Science (MSc)

Cardiovascular disease (CVD) is the leading cause of death in the United States. Recently, the gut microbiota has been implicated in the pathophysiology and progression of CVD. Experimental evidence suggests that high fat feeding alters the functional composition of the gut microbiota (dysbiosis); leading to increased translocation of the pro-inflammatory, endotoxin, and increased production of the pro-atherogenic, trimethylamine-N-oxide (TMAO). Together, these changes are hypothesized to accelerate CVD progression. Conversely, administration of gut microbiota modulating agents, such as antibiotics and probiotics, attenuate high fat feeding induced CVD in rodent models. In humans, the capacity to produce TMAO following L-carnitine or phosphatidylcholine challenges is abolished after receiving broad spectrum antibiotics for a period of one week. However, whether gut modulation over a longer period of time decreases fasting serum endotoxin, fasting plasma TMAO, and CVD risk in response to high fat feeding has been unexplored in humans. To address these issues we conducted a randomized, placebo controlled, parallel group designed, controlled feeding study in healthy, non-obese males receiving the multi-strain probiotic, VSL #3 (or placebo), while a consuming a high fat diet for 4-weeks. First, we tested the hypothesis that VSL #3 would attenuate the rise in serum endotoxin and consequent arterial stiffening following high fat feeding in healthy, non-obese males. Second, we tested the hypothesis that VSL #3 would attenuate the rise in plasma TMAO concentrations following high fat feeding in healthy, non-obese males. In contrast to our first hypotheses, serum endotoxin concentrations and arterial stiffness did not change in response to high fat feeding or with VSL#3 treatment. Interestingly, VSL #3 significantly attenuated the increase in body mass (+ 1.4±0.4 vs. +2.3±0.3 kg; P < 0.05) and fat mass (+0.7±0.1 vs. + 1.4±0.3 kg; P < 0.05) following high fat feeding compared to the placebo. In contrast to our second hypothesis, probiotic supplementation did not attenuate the rise in plasma TMAO following high fat feeding. Future studies are necessary to elucidate the mechanisms responsible for the prevention of body mass and fat mass gain with VSL#3 supplementation following high fat feeding. In addition, studies are needed to determine whether higher doses of VSL #3, other single or multispecies probiotics, prebiotics, or synbiotics attenuate the production of the proatherogenic, TMAO. / Ph. D.

No description available.