Oral ingestion of a hydrolyzed gelatin meal in subjects with normal weight and in obese patients: Postprandial effect on circulating gut peptides, glucose and insulin

Gut hormones Ighrelin, peptide YY (PYY) and ghrcagon-like peptide-1 (GLP-1)] are an important group of hormones that target appetite control. They are released from endocrine L cells of the small bowel in proportion to the volume, components and calories in a meal. In the current study, 20 g of gelatin (flavored and sweetened) were given to obese patients (n=12) and lean subjects (n=10). Subsequently, plasma samples were collected at-30-minute intervals rip to 180 minutes and glucose, insulin, PYY, GLP-1 and ghrelin were assayed using specific and sensitive immunofluorometric and radioimmunoassays. As expected, obese patients had normal serum glucose levels, higher serum insulin, and lower plasma concentration of ghrelin at all times compared to lean subjects. GLP-1 plasma levels were significantly elevated at 60 minutes, peaking at 120 minutes in obese patients and lean subjects. As a consequence, there was a significant rise in serum insulin levels with a significantly higher peak level at 60 min (obese) and 30 min (lean). There were no significant changes in PYY plasma concentrations and no correlation was found between body mass index and concentrations of ghrelin, PYY and GLP-1 in the group of obese patients. In conclusion, a single gelatin meal induces a rise in plasma GLP-1 followed by an increase in serum levels of insulin. These findings may be applied to maximize satiety in obese patients as a means of improving adherence to calorie-controlled diets as well as provide better control of diabetic patients.

Commensal microbiota is fundamental for the development of inflammatory pain

The ability of an individual to sense pain is fundamental for its capacity to adapt to its environment and to avoid damage. The sensation of pain can be enhanced by acute or chronic inflammation. In the present study, we have investigated whether inflammatory pain, as measured by hypernociceptive responses, was modified in the absence of the microbiota. To this end, we evaluated mechanical nociceptive responses induced by a range of inflammatory stimuli in germ-free and conventional mice. Our experiments show that inflammatory hypernociception induced by carrageenan, lipopolysaccharide, TNF-alpha, IL-1 beta, and the chemokine CXCL1 was reduced in germfree mice. In contrast, hypernociception induced by prostaglandins and dopamine was similar in germ-free or conventional mice. Reduction of hypernociception induced by carrageenan was associated with reduced tissue inflammation and could be reversed by reposition of the microbiota or systemic administration of lipopolysaccharide. Significantly, decreased hypernociception in germ-free mice was accompanied by enhanced IL-10 expression upon stimulation and could be reversed by treatment with an anti-IL-10 antibody. Therefore, these results show that contact with commensal microbiota is necessary for mice to develop inflammatory hypernociception. These findings implicate an important role of the interaction between the commensal microbiota and the host in favoring adaptation to environmental stresses, including those that cause pain.

Hematopoietic SCT modulates gut inflammation in experimental inflammatory bowel disease

Hematopoietic SCT (HSCT) and high-dose chemotherapy are being explored as therapy for various human refractory immune-mediated conditions, including inflammatory bowel diseases (IBD). Nevertheless, the exact immunological mechanisms by which the BM cells (BMCs) or immunosuppression provide remission from these diseases is not yet clear. In this work, we investigated the role of these therapies in the modulation of gut mucosal inflammation in an experimental model of IBD. Colitis was induced in mice by 2,4,6-trinitrobenzenesulfonic acid and after CY was administered (200 mg/kg) alone (CY group) or followed by BMCs infusion (HSCT group). Animals were followed for 60 days. Both HSCT and CY reduced the histopathological features of colitis significantly. Infused cells were localized in the gut, and a marked decrease of CD4(+) leukocytes in the inflammatory infiltrate on days +7 and +14 and of CD8(+) cells on day +7 was found in both treatments allied to impressive reduction of proinflammatory Th1 and Th17 cytokines. Although chemotherapy alone was the best treatment regarding the induction of immunosuppressive molecules, only HSCT resulted in increased survival rates compared with the control group. Our findings indicate that high-dose CY followed by HSCT is effective in the modulation of mucosal immunity and in accelerating immune reconstitution after BMT, thus providing valuable tools to support the development and understanding of novel therapeutic strategies for IBD. Bone Marrow Transplantation (2010) 45, 1562-1571; doi:10.1038/bmt.2010.6; published online 15 March 2010

Disturbances in microbiota - cause or effect?

IBD are a group of complex polygenetic diseases also involving environmental factors. Evidence for a role for bacteria in IBD include an increased abundance of mucosa-associated bacteria in IBD (which occurs even where there is no intestinal inflammation), and the positive impact of antibiotics on the progress of both Crohn's disease (CD) and ulcerative colitis (UC) of the pouch - pouchitis. Bacteria are necessary for most animal models of IBD. The increased abundance of mucosal bacteria in IBD is not non-specific because while some mucosal bacteria are more abundant this is not the case for all mucosal bacteria including the very abundant Bacteroides vulgatus. On the other hand, antibiotic treatments are not curative, and the humoral immune Ig response to bacterial antigens which is more evident in CD, appears to be polyclonal. While this argues against a role for specific bacteria causing a classical infection, certain mucosal bacteria may damage the mucosal barrier. This would promote invasion by other commensal mucosal bacteria triggering an immune response. Altered adaptive, and to a lesser extent, innate immunity have been extensively studied, and genetic defects in the CARD15 (or NOD2) gene that encodes a bacterial sensing protein modulating innate and adaptive immunity are strongly associated with ileal CD. However, the penetrance of the homozygous CARD15 frameshift mutation, which is the most strongly CD-associated genotype, is very low with only 4% of humans with this developing CD. Furthermore, mice with the same defects in CARD15 do not develop spontaneous ileitis or colitis. Therefore, there have to be other aetiological factor(s). Altered permeability is a consistent finding in subclinical CD. There are other data to suggest that altered mucin is an early event in UC. We propose that the pathogenesis of IBD is multifactorial involving specific mucosal bacteria, defective barrier function and altered mucosal immunity in an aetiology triangle.

Fate of swallowed interleukin 8 and TNF alpha and effect on the wistar rat gut

To evaluate the passage of cytokines through the gastrointestinal tract, we investigated the digestion of interleukin-8 (IL-8) and tumour necrosis factor α (TNFα), in vitro and in vivo, and their propensity to induce intestinal inflammation. We serially immuno-assayed IL-8 and TNFα solutions co-incubated with each of three pancreatin preparations at pH 4.5 and pH 8. We gavaged IL-8, TNFα and marker into 15 Wistar rats, and measured their faecal cytokine concentrations by ELISA and histologically examined their guts. IL-8 immunoreactivity was extinguished by all pancreatin preparations after 1 h of incubation at 37 °C. TNFα concentration progressively fell from 1 to 4 h with all enzyme preparations. Buffer control samples maintained their cytokine concentrations throughout incubation. No IL-8 or TNFα was detected in any rat faecal pellets. There was no significant proinflammatory effect of the gavaged cytokines on rat intestine. IL-8 and TNFα in aqueous solution could well be fully digested in the CF gut when transit time is normal and exogenous enzymes are provided, although cytokines swallowed in viscous sputum may be protected from such digestion. Copyright © 2011 Elsevier B.V. All rights reserved

Structure of the gut contents of Trichogramma australicum Girault (Hymenoptera : Trichogrammatidae) larvae fixed in situ in eggs of its host Helicoverpa armigera (Hubner) (Lepidoptera : Noctuidae)

Trichogramma australicum larvae develop most rapidly in younger eggs of its host, the pest lepidopteran Helicoverpa armigera . To establish how the developmental stage of the host affects the diet of T. australicum , larvae were fixed in situ in eggs of H. armigera of different ages and the structure of the egg contents and parasitoid gut contents examined histologically. Larvae feeding on newly laid host eggs contain primarily yolk particles in their gut, while larvae feeding on older hosts contain necrotic cells and yolk particles. The gut of T. australicum larvae does not contain organised tissue remnants, indicating that larvae feed primarily by sucking food into their pharynx and feed best on a mixture of particulate semisolids in a liquid matrix. Secretory structures of T. australicum larvae that could be involved in modifying the host environment were examined. The hindgut is modified to form an anal vesicle with a number of attributes suggesting that it may be a specialised secretory structure. The paired salivary glands open to the exterior via a common duct.

Identificação da microbiota fúngica de ambientes considerados assépticos

Objetivou-se isolar e identificar a microbiota fúngica em ambientes considerados assépticos, através de exposições com meios de cultivo adequados, em três épocas distintas do ano, antes e imediatamente após as manobras técnicas realizadas em três áreas de trabalho: ambiente aberto, ambiente fechado sem filtração de ar e ambiente fechado com filtração de ar, utilizadas em produção de imunobiológicos. Os meios ágar-Sabouraud e ágar-soja, enriquecidos com 0,2% de extrato de levedura e sem cloranfenicol, foram estudados quanto à sua eficácia no isolamento de bolores e leveduras, considerando-se o número de colônias desenvolvidas e a freqüência dos diversos fungos isolados. Isolaram-se 67 espécimens, sendo 64 fungos filamentosos (bolores) e três leveduras. Dos bolores, 54 pertenciam a 22 gêneros da divisão Deuteromycota, famílias Moniliaceae e Dematiaceae, cinco amostras filamentosas foram incluídas na ordem Agonomycetales (Mycelia Sterilia), e uma amostra foi classificada na divisão Deuteromycota, ordem Sphaeropsidales, classe Coelomycetes. Da divisão Zygomycota, ordem Mucorales, família Mucoraceae, um único mucoráceo foi identificado até gênero. As três leveduras pertenciam também à divisão Deuteromycota (Fungi Imperfecti), família Cryptococcaceae, e foram identificadas como sendo duas Rhodotorula rubra e uma Torulopsis candida. Comprovou-se que o número de colônias isoladas aumentou após a realização das monobras técnicas e que a filtração de ar através de filtros tipo HEPA, reduzindo o número de colônias isoladas nos ambientes fechados, aumenta a segurança do trabalho; comumente é recomendada para áreas de atividade técnica cujos resultados satisfatórios estão diretamente relacionados com uma baixa incidência de contaminantes.

Avaliação do efeito de um probiótico na performance zootécnica e microbiota entérica em coelhos (Oryctolagus cuniculus) de produção

A cunicultura é uma atividade pecuária em crescente desenvolvimento e isso traduz-se em novos desafios. Durante muitos anos a criação de coelhos recorreu em demasia ao uso de antimicrobianos com o objetivo de tratar e prevenir o aparecimento de diversas doenças. Paralelamente, estes compostos foram também usados como “promotores de crescimento”, visando essencialmente uma melhoria da eficiência digestiva. Porém, o uso indiscriminado destas substâncias levantou questões de saúde pública, como a emergência de estirpes bacterianas multirresistentes e a inerente disseminação de genes de resistência, possivelmente transferíveis ao Homem através da cadeia alimentar. No presente, existe uma enorme pressão para a adoção de estratégias que possibilitem uma redução massiva na quantidade de antimicrobianos administrados a espécies pecuárias. Este trabalho visou contribuir para o estudo de uma alternativa ao uso de antimicrobianos - os probióticos – enquanto suplementos alimentares constituídos por microrganismos vivos capazes de equilibrar a microbiota intestinal do hospedeiro. Para tal, foram constituídos dois grupos de coelhos com base na alimentação: i) grupo antibiótico, com acesso a um alimento composto suplementado com antibióticos e ii) o grupo probiótico alimentado com a mesma dieta, mas sem antibióticos e inoculado com um probiótico constituído por Escherichia coli e Enterococcus spp.. Ao longo de 22 dias de estudo foram monitorizados alguns indicadores produtivos e efetuadas recolhas periódicas de fezes para estudo microbiológico. A análise dos resultados zootécnicos permitiram verificar que o uso de probióticos em detrimento de antibióticos parece promover o crescimento de coelhos, tornando-se um método mais rentável na produção cunícula. Através de genotipagem por ERIC-PCR e PFGE, pretendeu-se verificar se as estirpes estranhas ao trato gastrointestinal dos coelhos seriam capazes de coloniza-lo, permanecendo ao longo do tempo de estudo. O facto de as estirpes inoculadas no probiótico terem sido encontradas ao longo dos dias de estudo nos coelhos aos quais foram administradas, sugere que os efeitos observados na performance zootécnica estejam relacionados com as estirpes administradas no probiótico, pelo que este poderá ser um sistema viável na substituição de antibióticos na alimentação de coelhos de produção.

Epidemiology and antimicrobial resistance of B. fragilis group organisms isolated from clinical specimen and human intestinal microbiota

Epidemiological aspects and the antimicrobial susceptibility profile of the Bacteroides fragilis group isolated from clinical and human intestinal specimens were examined in this study. B. fragilis group strains were isolated from 46 (37%) of 124 clinical specimens and the source of the samples was: Blood culture (3), intraabdominal infection (27), brain abscess (2), soft tissue infection (17), respiratory sinus (3), pleural aspirate (9), breast abscess (3), surgical infected wound (22), pelvic inflammatory disease (22), chronic otitis media (9) and miscellaneous (7). Intraabdominal and soft tissue infections were responsible for more than half of the clinical isolates. Susceptibility to penicillin, cefoxitin, tetracycline, metronidazole, chloramphenicol and clindamycin was examined. All isolates were susceptible to metronidazole and chloramphenicol. For clindamycin and cefoxitin the resistance rates observed were 21.7% and 10.9% respectively. Susceptibility profiles varied among the different species tested. A total of 37 species of B. fragilis group isolated from intestinal microbiota of individuals who had no antimicrobial therapy for at least 1 month before the sampling was also examined. All strains were also susceptible to chloramphenicol and motronidazole and the resistance rates to clindamycin and cefoxitin were 19.4% and 5.4% respectively. A few institutions, in Brazil, have monitored the antimicrobial susceptibility of B. fragilis group strains isolated from anaerobic infections. The resistance rates to cefoxitin and clindamycin and the variation in susceptibility patterns among the species isolated in this study emphasize the need for monitoring of susceptibility patterns of B. fragilis group organisms isolated, especially at our University Hospitals.

DETECTION OF IgM ANTIBODIES TO Schistosoma mansoni GUT-ASSOCIATED ANTIGENS FOR THE STUDY OF THE DYNAMICS OF SCHISTOSOMIASIS TRANSMISSION IN AN ENDEMIC AREA WITH LOW WORM BURDEN

For a period of 2 years, five follow-up measures of prevalence and incidence rates were estimated in a prospective study of S. mansoni infection in a group of schoolchildren who were living in a rural area of the Municipality of Itariri (São Paulo, Brazil), where schistosomiasis is transmitted by Biomphalaria tenagophila. Infection was determined by the examination of three Kato-Katz stool slides, and the parasitological findings were analyzed in comparison to serological data. In the five surveys, carried out at 6-month intervals (March-April and September-October), the prevalences were, respectively, 8.6, 6.8, 9.9, 5.8 and 17.2% by the Kato-Katz, and 56.5, 52.6, 60.8, 53.5 and 70.1% by the immunofluorescence test (IFT). Geometric mean egg counts were low: 57.8, 33.0, 35.6, 47.3 and 40.9 eggs per gram of feces, respectively. Of the total of 299 schoolchildren, who submitted five blood samples at 6-month intervals, one for each survey, 40% were IFT-positive throughout the study, and 22% were IFT-negative in all five surveys. Seroconversion from IFT negative to positive, indicating newly acquired S. mansoni infection, was observed more frequently in surveys carried out during March-April (after Summer holidays), than during September-October. Seasonal trends were not statistically significant for detection of S. mansoni eggs in stool. The results indicate that the use of IgM-IFT is superior to parasitological methods for detection of incidence of S. mansoni infection in areas with low worm burden.

INFLUENCE OF MICROBIOTA IN EXPERIMENTAL CUTANEOUS LEISHMANIASIS IN SWISS MICE

Infection of Swiss/NIH mice with Leishmania major was compared with infection in isogenic resistant C57BL/6 and susceptible BALB/c mice. Swiss/NIH mice showed self-controlled lesions in the injected foot pad. The production of high levels of interferon-g (IFN-g) and low levels of interleukin-4 (IL-4) by cells from these animals suggests that they mount a Th1-type immune response. The importance of the indigenous microbiota on the development of murine leishmaniasis was investigated by infecting germfree Swiss/NIH in the hind footpad with L. major and conventionalizing after 3 weeks of infection. Lesions from conventionalized Swiss/NIH mice were significantly larger than conventional mice. Histopathological analysis of lesions from conventionalized animals showed abscesses of variable shapes and sizes and high numbers of parasitized macrophages. In the lesions from conventional mice, besides the absence of abscess formation, parasites were rarely observed. On the other hand, cells from conventional and conventionalized mice produced similar Th1-type response characterized by high levels of IFN-g and low levels of IL-4. In this study, we demonstrated that Swiss/NIH mice are resistant to L. major infection and that the absence of the normal microbiota at the beginning of infection significantly influenced the lesion size and the inflammatory response at the site of infection.

Prevalência da microbiota no trato digestivo de fêmeas de Lutzomyia longipalpis (Lutz & Neiva, 1912) (Diptera: Psychodidae) provenientes do campo

No presente trabalho foram dissecados o trato digestivo de 245 fêmeas de Lutzomyia longipalpis originários da Gruta da Lapinha, Município de Lagoa Santa, MG, formando 7 grupos de 35 flebotomíneos. Das 8 espécies de bactérias isoladas houve uma predominância de bactérias Gram negativas (BGN) pertencentes ao grupo de não fermentadoras de açúcar das seguintes espécies: Acinetobacter lowffii, Stenotrophomonas maltophhilia, Pseudomonas putida e Flavimonas orizihabitans. No grupo das fermentadoras tivemos: Enterobacter cloacae e Klebsiella ozaenae. No grupo dos Gram positivos foram identificados Bacillus thuringiensis e Staphylococcus spp.