Gut Microbiota Imbalance Can Be Associated with Non-malabsorptive Small Bowel Shortening Regardless of Blind Loop.

INTRODUCTION: Some traditional bariatric surgery procedures may lead to functional gut shortening, which may unsettle the fine-tuned gastrointestinal physiology and affect gut microbiota balance. PURPOSE: Evaluate the gut microbiota behavior in rat models facing gut shortening due to intestinal bypass. MATERIALS AND METHODS: Wistar rats (n = 17) were randomly distributed in three groups: (1) sham group (n = 5); (2) blind loop group (n = 6); and (3) resection group (n = 6). Intestinal samples and feces were analyzed to measure bacterial concentrations (small intestinal bacterial overgrowth-SIBO) 12 weeks after the experimental procedures. Bacterial translocation (BT) was investigated in the mesenteric lymph node (MLN), liver, spleen, and lung of the animals. In addition, inflammatory aspects were investigated in their liver and small bowel through histological analysis. RESULTS: Regardless of blind loop, gut shortening groups recorded similar high level of bacterial concentrations in intestine compartments, greater than that of the sham group (p ≤ 0.05). BT was only observed in the MLN of gut shortening models, with higher percentage in the blind loop group (p ≤ 0.05). The gut and liver histopathological analysis showed similar low-grade chronic inflammation in both gut shortening groups, likely associated with SIBO/BT events. CONCLUSION: Sustained SIBO/BT was associated with proximal gut shortening in half regardless of blind loop, whereas the GI tract's ability to restore gut microbiota balance after a surgical challenge on the small bowel appears to be linked to the functional remaining gut.

Toxoplasma gondii oral infection induces intestinal inflammation and retinochoroiditis in mice genetically selected for immune oral tolerance resistance.

Toxoplasmosis is a worldwide disease with most of the infections originating through the oral route and generates various pathological manifestations, ranging from meningoencephalitis to retinochoroiditis and inflammatory bowel disease. Animal models for these pathologies are scarce and have limitations. We evaluated the outcome of Toxoplasma gondii oral infection with 50 or 100 cysts of the ME-49 strain in two lines of mice with extreme phenotypes of susceptibility (TS) or resistance (TR) to immune oral tolerance. Therefore, the aim of this study was to evaluate the behaviour of TS and TR mice, orally infected by T. gondii, and determine its value as a model for inflammatory diseases study. Mortality during the acute stage of the infection for TR was 50% for both dosages, while 10 and 40% of the TS died after infection with these respective dosages. In the chronic stage, the remaining TS succumbed while TR survived for 90 days. The TS displayed higher parasite load with lower intestinal inflammation and cellular proliferation, notwithstanding myocarditis, pneumonitis and meningoencephalitis. TR presented massive necrosis of villi and crypt, comparable to inflammatory bowel disease, with infiltration of lymphoid cells in the lamina propria of the intestines. Also, TR mice infected with 100 cysts presented intense cellular infiltrate within the photoreceptor layer of the eyes, changes in disposition and morphology of the retina cell layers and retinochoroiditis. During the infection, high levels of IL-6 were detected in the serum of TS mice and TR mice presented high amounts of IFN-γ and TNF-α. Both mice lineages developed different disease outcomes, but it is emphasized that TR and TS mice presented acute and chronic stages of the infection, demonstrating that the two lineages offer an attractive model for studying toxoplasmosis.

Morphometric changes in C57BL/6 mice retina infected by Toxoplasma gondii ME 49 strain.

This study evaluated the morphometric implications in C57BL/6 mouse retina infected by Toxoplasma gondii, ME 49 strain. Twenty C57BL/6 female mice were divided into group 1 (n=8, intraperitoneally infected with 30 cysts of T. gondii ME 49 strain) and group 2 (n=12 non-infected controls). The eyes were enucleated on the 60th day after infection, fixed and processed for light microscopy. Changes in retinal thickness and in the perimeter/area ratio (P/A) of the retinal layers were analyzed by digital morphometry. We considered that P/A was the measurement of retinal architecture distortion induced by toxoplasmosis. This study considered the ganglion cells and nerve fiber layers as a monolayer, thus six layers of retina were evaluated: photoreceptors (PRL), outer nuclear (ONL), outer plexiform (OPL), inner nuclear (INL), inner plexiform (IPL) and ganglion cells/nerve fiber monolayer (GNL). Histological analysis of infected mouse retina showed inflammatory infiltrate, necrosis, glial reaction and distortion of the retina architecture. It also presented increased thickness (167.8±24.9µm versus 121.1±15.4µm, in controls) and increased retinal thickness within the retinitis foci (187.7±16.6µm versus 147.9±12.2µm out of the retinitis foci). A statistically significant difference in P/A was observed between infected and uninfected mouse retinas. The same was observed in PRL, OPL, INL and GNL. Retinal morphometry may be used to demonstrate differences between infected and uninfected mouse retinas.

Análise da viabilidade e infectividade de taquizoítas de toxoplasma gondii em condições axênicas / Viability and infectivity analysis of toxoplasma gondii underaxenic conditions

Aims: To investigate the infectivity and viability of the tachyzoite form of Toxoplasma gondii maintained in axenic medium. Methods: Tachyzoites of Toxoplasma gondii isolated from infected mice were suspended in phosphate-buffered saline pH 7.2 or phosphate-buffered saline pH 7.2 plus 10% or 20% foetal calf serum, and incubated for 24 and for 48 hours at 37ºC. Afterwards the parasites were: (i) incubated with propidium iodide and analysed by flow cytometry, using the fluorescence-activated cell sorting (FACS) system; (ii) injected in mice to check the parasite viability in axenic conditions and, (iii) added to mouse embryonic fibroblasts to investigate their infectivity and ability to intracellular development. Results: Analysis by flow cytometry showed that Toxoplasma gondii tachyzoites maintained in phosphate-buffered saline supplemented with 20% foetal calf serum displayed high cellular viability. The parasites kept their infectivity in both the in vivo and the in vitro systems, respectively demonstrated by their ability to replicate in mice and to form rosettes in mouse embryonic fibroblasts. Conclusions: Our data open new perspectives for the study of different aspects of Toxoplasma gondii cell biology, including nutrition mechanisms, in vitro drug trials, or cellular and molecular studies to be performed directly on the parasite.

Objetivos: investigar a infectividade e a viabilidade de formas taquizoítas de Toxoplasma gondii mantidas em meio axênico. Métodos: taquizoítos de Toxoplasma gondii foram isolados de camundongos infectados, ressuspensos em tampão fosfato-salino pH 7,2 ou tampão fosfato-salino pH 7,2 mais soro fetal bovino a 10% ou 20% e incubados por 24 e 48 horas a 37ºC em atmosfera contendo 5% de CO2. A seguir os parasitos foram: (i) incubados com iodeto de propídio e analisados por citometria de fluxo utilizando a técnica de separação de células ativada por fluorescência (fluorescence activated cell sorting ? FACS); (ii) injetados em camundongos para analisar a infectividade dos parasitos mantidos em condições axênicas; e (iii) adicionados à cultura de fibroblastos de embrião de camundongo para investigar a sua capacidade infectiva e multiplicativa com formação de rosetas e lise celular. Resultados: a análise por citometria de fluxo mostrou que os taquizoítos de Toxoplasma gondii mantidos em tampão fosfato-salino suplementado com 20% de soro fetal bovino apresentaram elevada viabilidade celular. Os parasitos mantiveram sua infectividade nos sistemas in vivo e in vitro, respectivamente demonstrada por sua capacidade de se replicar em camundongos e de infectar culturas de fibroblastos. Conclusões: nossos dados abrem novas perspectivas para o estudo de diferentes aspectos da biologia do Toxoplasma gondii, incluindo mecanismos de nutrição, ensaios experimentais de drogas in vitro, ou estudos da biologia celular e molecular diretamente sobre o parasito.

Intravitreal bevacizumab in pigmented rabbit eyes: histological analysis 90 days after injection.

PURPOSE: To evaluate bevacizumab toxicity in neurosensorial retina and retinal pigment epithelium in pigmented rabbit eyes by means of histological studies. METHODS: Thirty eyes of fifteen rabbits were distributed into three groups: sham group (S), that received a 0.1 ml balanced saline solution (BSS) intravitreal injection (10 eyes); group 1, that received a 1.25 mg (0.1 ml) bevacizumab intravitreal injection (10 eyes); and group 2, that received a 2.5 mg (0.1 ml) bevacizumab intravitreal injection (10 eyes). Rabbits were sacrificed 90 days after the procedure and both eyes of each rabbit were enucleated. A histological examination of neurosensorial retina and retinal pigmented epithelium (RPE) was performed. Its morphological features and layer thickness were also analyzed. RESULTS: No histological differences in neurosensorial retina or in retinal pigmented epithelium were found and layer thickness did not differ significantly between balanced saline solution-injected eyes and bevacizumab-injected eyes. CONCLUSION: After a 90-day follow-up period, a single 1.25 or 2.5 mg bevacizumab intravitreal injection did not lead to toxic damage in the neurosensorial retina and retinal pigment epithelium of pigmented rabbit eyes, and it appears to be a safe procedure for retinal neovascular diseases.

Intravitreal bevacizumab in pigmented rabbit eyes: histological analysis 90 days after injection / Bevacizumabe intravítreo em olhos de coelhos não albinos: análise histológica 90 dias após a injeção

PURPOSE: To evaluate bevacizumab toxicity in neurosensorial retina and retinal pigment epithelium in pigmented rabbit eyes by means of histological studies. METHODS: Thirty eyes of fifteen rabbits were distributed into three groups: sham group (S), that received a 0.1 ml balanced saline solution (BSS) intravitreal injection (10 eyes); group 1, that received a 1.25 mg (0.1 ml) bevacizumab intravitreal injection (10 eyes); and group 2, that received a 2.5 mg (0.1 ml) bevacizumab intravitreal injection (10 eyes). Rabbits were sacrificed 90 days after the procedure and both eyes of each rabbit were enucleated. A histological examination of neurosensorial retina and retinal pigmented epithelium (RPE) was performed. Its morphological features and layer thickness were also analyzed. RESULTS: No histological differences in neurosensorial retina or in retinal pigmented epithelium were found and layer thickness did not differ significantly between balanced saline solution-injected eyes and bevacizumab-injected eyes. CONCLUSION: After a 90-day follow-up period, a single 1.25 or 2.5 mg bevacizumab intravitreal injection did not lead to toxic damage in the neurosensorial retina and retinal pigment epithelium of pigmented rabbit eyes, and it appears to be a safe procedure for retinal neovascular diseases.

OBJETIVOS: Avaliar a toxicidade do bevacizumabe na retina neurossensorial e epitélio pigmentado da retina (EPR) em olhos de coelhos não albinos pelos estudos histológicos. MÉTODOS: Trinta olhos de 15 coelhos foram distribuídos em três grupos: 10 olhos no grupo placebo (P), que recebeu uma injeção intravítrea de 0,1 ml de solução salina balanceada (SSB); 10 olhos no grupo 1, que recebeu uma injeção intravítrea de 1,25 mg (0,1 ml) de bevacizumabe; e 10 olhos no grupo 2, que recebeu uma injeção intravítrea de 2,5 mg (0,1 ml) de bevacizumabe. Os coelhos tiveram seus dois olhos enucleados sob anestesia geral e submetidos à eutanásia 90 dias após a injeção. Foi realizada avaliação histológica na retina neurossensorial e no epitélio pigmentado da retina e seus aspectos morfológicos e espessuras das camadas retinianas foram analisadas. RESULTADOS: Não foi observada diferença significante entre a morfologia histológica e espessura das camadas retinianas entre o grupo P (SSB) e os grupos 1 e 2 (bevacizumabe 1,25 mg e 2,5 mg, respectivamente). CONCLUSÃO: Após um seguimento de 90 dias, uma única injeção intravítrea de bevacizumabe com 1,25 e 2,5 mg não levou a danos histológicos na retina neurossensorial e epitélio pigmentado da retina em olhos de coelhos não albinos e parece ser um procedimento seguro para o tratamento das doenças neovasculares da retina.

Alterações morfológicas na retina de camundongos C57BL/6 infectados com Toxoplasma gondii (Apicomplexa, Sarcocystidae) / Morphological alterations of the retina of mice C57BL/6 infected with Toxoplasma gondii (Apicomplexa, Sarcocystidae)

Toxoplasmose, cujo agente etiológico é o Toxoplasma gondii acontece em cerca de 10 a 30 por cento de indivíduos em todo o mundo. No Brasil, a prevalência sorológica para o T. gondii varia entre 50 e 80 por cento da população saudável. A infecção pelo T. gondii em humanos é muito comum, contudo, a doença clínica está restrita a indivíduos imunocomprometidos e à transmissão congênita... O principal objetivo deste trabalho é documentar as alterações morfológicas e o comprometimento da retina na infecção pelo T. gondii no modelo murino, utilizando camundongos C57BL/6, infectados pelas vias congênita, intravitreal e intraperitoneal. Camundongos C57BL/6 fêmeas adultas foram divididos em três grupos experimentais: grupo 1: embriões oriundos de fêmeas grávidas inoculadas via oral (gavagem) com 5 cistos de T. gondii no 10º dia de gestação; grupo 2: fêmeas adultas inoculadas via intravitreal (i.v.) com 5x103 bradizoítas, oriundos de cistos rompidos; e grupo 3: fêmeas adultas inoculadas via intraperitoneal (i.p.) com 50 cistos de T. gondii. Os olhos foram enucleados durante o curso da infecção e avaliados utilizando as microscopias de luz e eletrônica de transmissão. A dosagem de anticorpos IgM e IgG revelou o curso da doença, caracterizando as fases aguda e crônica. A análise histopatológica dos olhos dos embriões não revelou a presença do parasita... Nos grupos 2 e 3 foram observados parasitas no interior dos vasos, acompanhados de infiltrado inflamatório, edema, migração do epitélio pigmentado da retina (EPR) e formação de lacunas nos segmentos externos dos fotorreceptores (FTR). Os cistos foram evidenciados 60 dias pós-infecção, na camada nuclear interna da retina. A análise ultra-estrutural mostrou detalhes dos cistos e das células da retina, e alterações oriundas dos infiltrados inflamatórios e da migração celular nas camadas externas e internas da retina. Concluímos que as lesões observadas foram focais e restritas à retina. Os segmentos externos dos FTR foram as estruturas mais alteradas da retina, provavelmente devido a migração das células inflamatórias e do EPR, alterando assim, sua arquitetura. A presença do parasita nos vasos dos tecidos oculares, nos animais inoculados via i.v. e i.p., em todos os períodos examinados, indica a existência de parasitas circulantes, mesmo na fase crônica da doença, sugerindo que sejam oriundos do rompimento de cistos.