Disruption of the early-life microbiota alters Peyer's patch development and germinal center formation in gastrointestinal-associated lymphoid tissue.

During postnatal development, both the maturing microbiome and the host immune system are susceptible to environmental perturbations such as antibiotic use. The impact of timing in which antibiotic exposure occurs was investigated by treating mice from days 5-9 with amoxicillin or azithromycin, two of the most commonly prescribed medications in children. Both early-life antibiotic regimens disrupted Peyer's patch development and immune cell abundance, with a sustained decrease in germinal center formation and diminished intestinal immunoglobulin A (IgA) production. These effects were less pronounced in adult mice. Through comparative analysis of microbial taxa, Bifidobacterium longum abundance was found to be associated with germinal center frequency. When re-introduced to antibiotic-exposed mice, B. longum partially rescued the immunological deficits. These findings suggest that early-life antibiotic use affects the development of intestinal IgA-producing B cell functions and that probiotic strains could be used to restore normal development after antibiotic exposure.

A single early-in-life antibiotic course increases susceptibility to DSS-induced colitis.

BACKGROUND: There is increasing evidence that the intestinal microbiota plays a crucial role in the maturation of the immune system and the prevention of diseases during childhood. Early-life short-course antibiotic use may affect the progression of subsequent disease conditions by changing both host microbiota and immunologic development. Epidemiologic studies provide evidence that early-life antibiotic exposures predispose to inflammatory bowel disease (IBD). METHODS: By using a murine model of dextran sodium sulfate (DSS)-induced colitis, we evaluated the effect on disease outcomes of early-life pulsed antibiotic treatment (PAT) using tylosin, a macrolide and amoxicillin, a beta-lactam. We evaluated microbiota effects at the 16S rRNA gene level, and intestinal T cells by flow cytometry. Antibiotic-perturbed or control microbiota were transferred to pups that then were challenged with DSS. RESULTS: A single PAT course early-in-life exacerbated later DSS-induced colitis by both perturbing the microbial community and altering mucosal immune cell composition. By conventionalizing germ-free mice with either antibiotic-perturbed or control microbiota obtained 40 days after the challenge ended, we showed the transferrable and direct effect of the still-perturbed microbiota on colitis severity in the DSS model. CONCLUSIONS: The findings in this experimental model provide evidence that early-life microbiota perturbation may increase risk of colitis later in life.

Long-Term Effects of Early-Life Antibiotic Exposure on Resistance to Subsequent Bacterial Infection.

Early-life antibiotic exposure may provoke long-lasting microbiota perturbation. Since a healthy gut microbiota confers resistance to enteric pathogens, we hypothesized that early-life antibiotic exposure would worsen the effects of a bacterial infection encountered as an adult. To test this hypothesis, C57BL/6 mice received a 5-day course of tylosin (macrolide), amoxicillin (ß-lactam), or neither (control) early in life and were challenged with Citrobacter rodentium up to 80 days thereafter. The early-life antibiotic course led to persistent alterations in the intestinal microbiota and even with pathogen challenge 80 days later worsened the subsequent colitis. Compared to exposure to amoxicillin, exposure to tylosin led to greater disease severity and microbiota perturbation. Transferring the antibiotic-perturbed microbiota to germfree animals led to worsened colitis, indicating that the perturbed microbiota was sufficient for the increased disease susceptibility. These experiments highlight the long-term effects of early-life antibiotic exposure on susceptibility to acquired pathogens.IMPORTANCE The gastrointestinal microbiota protects hosts from enteric infections; while antibiotics, by altering the microbiota, may diminish this protection. We show that after early-life exposure to antibiotics host susceptibility to enhanced Citrobacter rodentium-induced colitis is persistent and that this enhanced disease susceptibility is transferable by the antibiotic-altered microbiota. These results strongly suggest that early-life antibiotics have long-term consequences on the gut microbiota and enteropathogen infection susceptibility.

Antibiotic-induced acceleration of type 1 diabetes alters maturation of innate intestinal immunity.

The early-life intestinal microbiota plays a key role in shaping host immune system development. We found that a single early-life antibiotic course (1PAT) accelerated type 1 diabetes (T1D) development in male NOD mice. The single course had deep and persistent effects on the intestinal microbiome, leading to altered cecal, hepatic, and serum metabolites. The exposure elicited sex-specific effects on chromatin states in the ileum and liver and perturbed ileal gene expression, altering normal maturational patterns. The global signature changes included specific genes controlling both innate and adaptive immunity. Microbiome analysis revealed four taxa each that potentially protect against or accelerate T1D onset, that were linked in a network model to specific differences in ileal gene expression. This simplified animal model reveals multiple potential pathways to understand pathogenesis by which early-life gut microbiome perturbations alter a global suite of intestinal responses, contributing to the accelerated and enhanced T1D development.

Intergenerational transfer of antibiotic-perturbed microbiota enhances colitis in susceptible mice.

Antibiotic exposure in children has been associated with the risk of inflammatory bowel disease (IBD). Antibiotic use in children or in their pregnant mother can affect how the intestinal microbiome develops, so we asked whether the transfer of an antibiotic-perturbed microbiota from mothers to their children could affect their risk of developing IBD. Here we demonstrate that germ-free adult pregnant mice inoculated with a gut microbial community shaped by antibiotic exposure transmitted their perturbed microbiota to their offspring with high fidelity. Without any direct or continued exposure to antibiotics, this dysbiotic microbiota in the offspring remained distinct from controls for at least 21 weeks. By using both IL-10-deficient and wild-type mothers, we showed that both inoculum and genotype shape microbiota populations in the offspring. Because IL10-/- mice are genetically susceptible to colitis, we could assess the risk due to maternal transmission of an antibiotic-perturbed microbiota. We found that the IL10-/- offspring that had received the perturbed gut microbiota developed markedly increased colitis. Taken together, our findings indicate that antibiotic exposure shaping the maternal gut microbiota has effects that extend to the offspring, with both ecological and long-term disease consequences.

A single early-in-life macrolide course has lasting effects on murine microbial network topology and immunity.

Broad-spectrum antibiotics are frequently prescribed to children. Early childhood represents a dynamic period for the intestinal microbial ecosystem, which is readily shaped by environmental cues; antibiotic-induced disruption of this sensitive community may have long-lasting host consequences. Here we demonstrate that a single pulsed macrolide antibiotic treatment (PAT) course early in life is sufficient to lead to durable alterations to the murine intestinal microbiota, ileal gene expression, specific intestinal T-cell populations, and secretory IgA expression. A PAT-perturbed microbial community is necessary for host effects and sufficient to transfer delayed secretory IgA expression. Additionally, early-life antibiotic exposure has lasting and transferable effects on microbial community network topology. Our results indicate that a single early-life macrolide course can alter the microbiota and modulate host immune phenotypes that persist long after exposure has ceased.High or multiple doses of macrolide antibiotics, when given early in life, can perturb the metabolic and immunological development of lab mice. Here, Ruiz et al. show that even a single macrolide course, given early in life, leads to long-lasting changes in the gut microbiota and immune system of mice.

Metabolic and metagenomic outcomes from early-life pulsed antibiotic treatment.

Mammalian species have co-evolved with intestinal microbial communities that can shape development and adapt to environmental changes, including antibiotic perturbation or nutrient flux. In humans, especially children, microbiota disruption is common, yet the dynamic microbiome recovery from early-life antibiotics is still uncharacterized. Here we use a mouse model mimicking paediatric antibiotic use and find that therapeutic-dose pulsed antibiotic treatment (PAT) with a beta-lactam or macrolide alters both host and microbiota development. Early-life PAT accelerates total mass and bone growth, and causes progressive changes in gut microbiome diversity, population structure and metagenomic content, with microbiome effects dependent on the number of courses and class of antibiotic. Whereas control microbiota rapidly adapts to a change in diet, PAT slows the ecological progression, with delays lasting several months with previous macrolide exposure. This study identifies key markers of disturbance and recovery, which may help provide therapeutic targets for microbiota restoration following antibiotic treatment.

Helicobacter pylori: the balance between a role as colonizer and pathogen.

The isolation of Helicobacter pylori from the human stomach produced significant changes in how gastroenterologists, immunologists, epidemiologists, pathologists and microbiologists have approached gastro-duodenal diseases in the last half of the XX century. However, research of this organism has progressed greatly in the first decade of this century, evidence suggest that H. pylori is associated with disease only in humans older than 40 years, while, the lack of H. pylori colonization is associated with the emergence of new diseases, particularly in younger individuals. These differing effects of H. pylori colonization have created two contrasting concepts: the 'bad' and the 'good' Helicobacter. Following from renewed interest in the normal human microbiome, we need to reconsider our definitions and perhaps recognize that H. pylori might be a normal member of the human gastric microbiome in ancient humans that gradually, as results of the improvement in our environment, is disappearing.

Isolating, immunophenotyping and ex vivo stimulation of CD4+ and CD8+ gastric lymphocytes during murine Helicobacter pylori infection.

Helicobacter pylori infection is associated with severe chronic inflammation, yet the host immune response is rarely able to clear the bacterium. Thymus derived lymphocyte populations such as T helper 1, T helper 17, and T regulatory cells are known to play important roles in the chronicity of H. pylori infection as well as contributing to ongoing gastric pathology. It is yet to be established how these immune cell populations interact in the gastric environment during H. pylori infection. Mouse models of infection offer an opportunity to investigate these interactions in detail. Flow cytometric analysis provides excellent lymphocyte characterization due to its high specificity, sensitivity and potential to perform multiple simultaneous measurements. However, this requires a viable enriched single cell suspension after adequate tissue dissociation, which poses a challenge due to the heterogeneity of gastric tissue. We have evaluated several isolation techniques and have optimized a protocol to isolate and enrich lymphocytes from the H. pylori-infected murine stomach. EDTA/DTT followed by Collagenase IV digestion successfully dissociates an average of 1 × 107 cells per mouse. Further enrichment using Lympholyte M gradient yields on average 4 × 106 CD45+ lymphocytes per stomach. Following isolation we compared lymphocyte stimulation by CD3/CD28, phorbol 12-myristate 13-acetate (PMA) and ionomycin or H. pylori lysate and determined that CD3/CD28 effectively induces stimulation of IFNγ and IL 17A, but impairs Foxp3 expression. Using an optimized protocol we observed a 2-fold increase of CD8+ IFNγ-expressing lymphocytes localized specifically to the gastric compartment during H. pylori infection. The mechanisms of H. pylori immunopathogenesis are still considered enigmatic, therefore this optimized protocol can help delineate further novel immune cell targets that mediate H. pylori-induced pathology and identify the correlates of immunity for vaccine development.

Helicobacter pylori in the pathogenesis of gastric cancer and gastric lymphoma.

Chronic gastric infection by the gram-negative bacterium Helicobacter pylori is strongly associated with the development of distal gastric carcinoma and gastric mucosal lymphoma in humans. Eradication of H. pylori with combination antibiotic therapy cures most cases of gastric lymphoma and slows progression to gastric adenocarcinoma. H. pylori promotes gastric neoplasia, principally via the induction of an intense gastric inflammatory response that lasts over decades. This persistent inflammatory state produces chronic oxidative stress and adaptive changes in gastric epithelial and immune cell pathobiology that in a minority of infected subjects eventually proceeds to frank neoplastic transformation.

Estenosis distal del esófago por restos embrionarios de tejido traqueo bronquial (coristoma condioepitelial: informe de un paciente / Distal stenosis of the esophagus caused by embryonic remants of tracheobronchial tissue (chondro-epithelial chroristoma). Report of a patient

Los procesos patológicos más frecuentes que causan estenosis congénita del esófago son hernia hiatal, membranas esofágicas, fístulas traqueoesofágicas, quistes faríngeos, etc.; el menos conocido por su rareza es la presencia de restos embrionarios traqueobronquiales. En la literatura mundial se encontró la comunicación por diferentes autores (1, 2, 3, 4) de 8 casos, incluyendo una serie de 5 casos de Ishida y colaboradores (3); en todos ellos el diagnóstico se confundió con Acalasia, debido a la imagen radiológica. En ninguno se practicó manometría esofágica y solamente el estudio histopatológico evidenció los restos traqueobronquiales. En este trabajo reportamos un caso de gran interés por su rareza, de esteosis congénita del esófago en su porción distal por un anillo fibroso de restos traqueobronquiales, cursando además con cuerpo extraño detenido a nivel de dicha estenosis (una moneda mayor de 2 años de edad, en quien clínica y radiológicamente se pensó en acalasia, sin embargo el estudio endoscópico no fue determinante de dicho diagnóstico y en cambio la manometría esofágica lo descartó totalmente debido a la presencia de onda primario en el trazo

El empleo de una férula de silastic en la prevención de la estenosis del esófago secundaria a quemadura por ingestión de cáustico: informe preliminar / The use of a silastic tube in the prevention of esophageal stenosis following burn by caustic ingestion: preliminary report

Se informa el resultado obtenido en 53 pacientes que sufrieron esofagitis grado III por quemadura debida a ingestión de substancias caústicas y quienes fueron tratados mediante la aplicación de una férula esofágica de silastic por 4 semanas. En 47 de ellos, después de 6 meses de observación, no se encontró la estenosis y los estudios clínicos, radiológicos, endoscópicos y manométricos del esófago, fueron normales. De acuerdo a los resultados obtenidos, la aplicación de una férula en el esófago es un método efectivo para prevenir las estenosis esofágicas consecutivas a quemaduras por ingesta de sustancias caústicas

Esófago de Barrett / Barrett's esophagus

Se denomina esófago de Barrett a la entidad clínica que asocia reflujo gastro-esofágico, úlcera esofagitis y/o estenosis, con la presencia de epitelio columnar metaplástico en la porción distal del esófago; esta metaplasia puede ser de origen congénito o adquirido, siendo esta última teoría la más aceptada. Se presenta en este informe un estudio de 37 pacientes, 16 niños y 21 adultos, todos con estenosis esofágica demostrada radiológicamente, se encontró en la endoscopia esofágica estenosis en el 100%, úlcera esofágica en 35 de ellos (94%), reflujo gastro-esofágico y esofagitis en 8 respectivamente (21%); las biopsias transendoscópicas en los 37 pacientes (100%) demostró la presencia de epitelio columnas. Todos los enfermos sometidos a dilatación de la estenosis previa a la realización de intervención quirúrgica con técnica anti-reflujo. En 22 (59%), 16 niños y 6 adultos, fue necesario continuar las dilataciones post-cirugía por persistencia de la estenosis, hasta obtener un calibre aceptable en un tiempo promedio de 4 meses. En 7 pacientes se llevaron a cabo controles endoscópicos a los 10 o 12 meses después de la cirugía encontrándose en 4 de ellas buen calibre del esófago, ausencia de reflujo y esofagitis, así como regresión del epitelio columnar a epitelio escamosos estratificado; en 2 persistía el reflujo y la esofagitis, con recidiva de estenosis y permanencia de epitelio columnar y en 1 paciente hubo malignización de tipo adenocarcinoma. El esofágo de Barrett es más frecuente de lo que generalmente se cree, por lo que todo paciente portador de reflujo gastro-esofágico debe ser estudiado minuciosamente con endoscopía y biopsias, con objeto de establecer la presencia de epitelio columnar metaplástico, diagnóstico irrefutable de esófago de Barrett