Academic literature on the topic 'Postbiotics'

Postbiotics are non-viable bacterial products or metabolic byproducts produced by probiotic microorganisms that have biologic activity in the host. Postbiotics are functional bioactive compounds, generated in a matrix during anaerobic fermentation of organic nutrients like prebiotics, for the generation of energy in the form of adenosine triphosphate. The byproducts of this metabolic sequence are called postbiotics, these are low molecular weight soluble compounds either secreted by live microflora or released after microbial cell lysis. A few examples of widely studied postbiotics are short-chain fatty acids, microbial cell fragments, extracellular polysaccharides, cell lysates, teichoic acid, vitamins, etc. Presently, prebiotics and probiotics are the products on the market; however, postbiotics are also gaining a great deal of attention. The numerous health advantages of postbiotic components may soon lead to an increase in consumer demand for postbiotic supplements. The most recent research aspects of postbiotics in the food and pharmaceutical industries are included in this review. The review encompasses a brief introduction, classification, production technologies, characterization, biological activities, and potential applications of postbiotics.

Although the prevalence of metabolic disorders has progressively increased over the past few decades, metabolic disorders can only be effectively treated with calorie restriction and improved physical activity. Recent research has focused on altering the gut microbiome using prebiotics, probiotics, and postbiotics because various metabolic syndromes are caused by gut microbial dysbiosis. Postbiotics, substances produced or released by microorganism metabolic activities, play an important role in maintaining and restoring host health. Because postbiotics have a small amount of literature on their consumption, there is a need for more experiments on short- and long-term intake. This review discusses current postbiotic research, categories of postbiotics, positive roles in metabolic syndromes, and potential therapeutic applications. It covers postbiotic pleiotropic benefits, such as anti-obesity, anti-diabetic, and anti-hypertensive qualities, that could aid in the management of metabolic disorders. Postbiotics are promising tools for developing health benefits and therapeutic goals owing to their clinical, technical, and economic properties. Postbiotic use is attractive for altering the microbiota; however, further studies are needed to determine efficacy and safety.

Postbiotics from Lactobacillus plantarum have been reported to improve growth performance, nutrient utilization, immune status and gut health in livestock. However, there is scarce information on the antioxidant activity of postbiotics and its modulation of antioxidant activity and rumen barrier function in animals. We investigated the antioxidant activity of postbiotics from L. plantarum RG14, RG11 and TL1 and dietary effects in post-weaning lambs on serum and ruminal antioxidant activity, hepatic antioxidant enzymes and ruminal barrier function. Postbiotic RG14 showed the highest antioxidant activity in both 2,2-diphenyl-1-picryl-hydrazyl (DPPH) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay and was chosen to be evaluated in animal trials. Twelve post-weaning Dorper lambs were allotted to the control group and postbiotic group (0.9% (v/w) postbiotic RG14). The improvement in antioxidant activity of the postbiotic group was observed by greater glutathione peroxidase (GPX) in serum and ruminal fluid and lower serum TBARS. The findings were strengthened by the upregulation of hepatic GPX1, GPX4 and copper, zinc superoxide dismutase (Cu/Zn SOD) in the postbiotic group. Lambs received postbiotics had higher regulation of rumen barrier function through upregulation of tight junction protein (TJP), occludin (OCLD), claudin-1 (CLDN1) and CLDN4. The current study demonstrated that dietary postbiotics enhanced the serum and ruminal fluid antioxidant activity, reduced the serum lipid peroxidation and upregulated hepatic antioxidant enzymes and ruminal barrier function.

In the 21st century, compressive health and functional foods are advocated by increasingly more people in order to eliminate sub-health conditions. Probiotics and postbiotics have gradually become the focus of scientific and nutrition communities. With the maturity and wide application of probiotics, the safety concerns and other disadvantages are non-negligible as we review here. As new-era products, postbiotics continue to have considerable potential as well as plentiful drawbacks to optimize. “Postbiotic” has been defined as a “preparation of inanimate microorganisms and/or their components that confers a health benefit on the host”. Here, the evolution of the concept “postbiotics” is reviewed. The underlying mechanisms of postbiotic action are discussed. Current insight suggests that postbiotics exert efficacy through protective modulation, fortifying the epithelial barrier and modulation of immune responses. Finally, we provide an overview of the comparative advantages and the current application in the food industry at pharmaceutical and biomedical levels.

Postbiotics are functional bioactive compounds, generated in a matrix during fermentation, which may be used to promote health. The term postbiotics can be regarded as an umbrella term for all synonyms and related terms of these microbial fermentation components. Therefore, postbiotics can include many different constituents including metabolites, short-chain fatty acids (SCFAs), microbial cell fractions, functional proteins, extracellular polysaccharides (EPS), cell lysates, teichoic acid, peptidoglycan-derived muropeptides and pili-type structures. Postbiotics is also a rather new term in the ‘-biotics’ field. Where consensus exists for the definitions of pre- and probiotics, this is not yet the case for postbiotics. Here we propose a working definition and review currently known postbiotic compounds, their proposed mechanisms, clinical evidence and potential applications. Research to date indicates that postbiotics can have direct immunomodulatory and clinically relevant effects and evidence can be found for the use of postbiotics in healthy individuals to improve overall health and to relief symptoms in a range of diseases such as infant colic and in adults atopic dermatitis and different causes of diarrhea.

Postbiotics are a new category of biotics that have the potential to confer health benefits but, unlike probiotics, do not require living cells to induce health effects and thus are not subject to the food safety requirements that apply to live microorganisms. Postbiotics are defined as a “preparation of inanimate microorganisms and/or their components that confers a health benefit on the host”. Postbiotic components include short-chain fatty acids, exopolysaccharides, vitamins, teichoic acids, bacteriocins, enzymes and peptides in a non-purified inactivated cell preparation. While research into postbiotics is in its infancy, there is increasing evidence that postbiotics have the potential to modulate human health. Specifically, a number of postbiotics have been shown to improve gut health by strengthening the gut barrier, reducing inflammation and promoting antimicrobial activity against gut pathogens. Additionally, research is being conducted into the potential application of postbiotics to other areas of the body, including the skin, vagina and oral cavity. The purpose of this review is to set out the current research on postbiotics, demonstrate how postbiotics are currently used in commercial products and identify a number of knowledge gaps where further research is needed to identify the potential for future applications of postbiotics.

AbstractIn 2019, the International Scientific Association for Probiotics and Prebiotics (ISAPP) convened a panel of experts specializing in nutrition, microbial physiology, gastroenterology, paediatrics, food science and microbiology to review the definition and scope of postbiotics. The term ‘postbiotics’ is increasingly found in the scientific literature and on commercial products, yet is inconsistently used and lacks a clear definition. The purpose of this panel was to consider the scientific, commercial and regulatory parameters encompassing this emerging term, propose a useful definition and thereby establish a foundation for future developments. The panel defined a postbiotic as a “preparation of inanimate microorganisms and/or their components that confers a health benefit on the host”. Effective postbiotics must contain inactivated microbial cells or cell components, with or without metabolites, that contribute to observed health benefits. The panel also discussed existing evidence of health-promoting effects of postbiotics, potential mechanisms of action, levels of evidence required to meet the stated definition, safety and implications for stakeholders. The panel determined that a definition of postbiotics is useful so that scientists, clinical triallists, industry, regulators and consumers have common ground for future activity in this area. A generally accepted definition will hopefully lead to regulatory clarity and promote innovation and the development of new postbiotic products.

The gastrointestinal microbiome comprises trillions of bacteria, and is a vitally important organ with wide ranging effects on pet health Food impacts the composition and metabolism of the microbiome, as well as the production of postbiotics, which are bioactive end products of microbial consumption of prebiotics. Postbiotics include metabolites of nutrients like fatty acids, amino acids, vitamins and polysaccharides. Also gut bacteria can produce postbiotics from plant antioxidants like polyphenols. A growing body of evidence has shown that influencing postbiotic production may have beneficial effects on pet health. Soluble and insoluble fibers are commonly used sources of prebiotics in the pet food industry, some of these fibers have polyphenols bound to them. Understanding the impact of each fiber type on the microbiome composition, metabolism and postbiotic production provides insights into formulating foods that are optimal for pet health.

The scientific community has proposed terms such as non-viable probiotics, paraprobiotics, ghostbiotics, heat-inactivated probiotics or, most commonly, postbiotics, to refer to inanimate microorganisms and/or their components that confer health benefits. This article addresses the various characteristics of different definitions of ‘postbiotics’ that have emerged over past years. In 2021, the International Scientific Association for Probiotics and Prebiotics (ISAPP) defined a postbiotic as “a preparation of inanimate microorganisms and/or their components that confers a health benefit on the host”. This definition of postbiotic requires that the whole or components of inactivated microbes be present, with or without metabolic end products. The definition proposed by ISAPP is comprehensive enough to allow the development of postbiotics from different microorganisms, to be applied in different body sites, encouraging innovation in a promising area for any regulatory category and for companion or production animals, and plant or human health. From a technological perspective, probiotic products may contain inanimate microorganisms, which have the potential to impart a health benefit. However, their contribution to health in most cases has not been established, even if at least one probiotic has been shown to confer the same health benefit by live or inanimate cells.

The purpose of this work was to evaluate the impacts of feeding different postbiotics on oxidative stress markers, physiological stress indicators, lipid profile and meat quality in heat-stressed broilers. A total of 252 male Cobb 500 (22-day-old) were fed with 1 of 6 diets: A basal diet without any supplementation as negative control (NC); basal diet + 0.02% oxytetracycline served as positive control (PC); basal diet + 0.02% ascorbic acid (AA); or the basal diet diet + 0.3% of RI11, RS5 or UL4 postbiotics. Postbiotics supplementation, especially RI11 increased plasma activity of total-antioxidant capacity (T-AOC), catalase (CAT) and glutathione (GSH), and decreased alpha-1-acid-glycoprotein (α1-AGP) and ceruloplasmin (CPN) compared to NC and PC groups. Meat malondialdehyde (MDA) was lower in the postbiotic groups than the NC, PC and AA groups. Plasma corticosterone, heat shock protein70 (HSP70) and high density lipoprotein (HDL) were not affected by dietary treatments. Postbiotics decreased plasma cholesterol concentration compared to other groups, and plasma triglyceride and very low density lipoprotein (VLDL) compared to the NC group. Postbiotics increased breast meat pH, and decreased shear force and lightness (L*) compared to NC and PC groups. The drip loss, cooking loss and yellowness (b*) were lower in postbiotics groups compared to other groups. In conclusion, postbiotics particularly RI11 could be used as an alternative to antibiotics and natural sources of antioxidants for heat-stressed broilers.

As the use of probiotics and postbiotics is increasingly gaining ground in the past decade, the possibility of using bacterial strains with postbiotic activity to restore homeostasis in pathologic conditions such as IBD is extensively debated. However, clinical data as far as induction of remission is concerned has not been encouraging so far, while researchers observe that only a small number of treatments which seem promising on in vitro or mouse models translate to significant clinical benefit. This could mean that the models used so far to test potential treatments are not an accurate representation of the human intestine's rather complex micro-environment, and thus there is a need for the development of more relevant models. In this thesis, a novel organ culture model for polarized stimulation of intestinal mucosa is described. In the intestine, apical and basolateral challenge of the mucosal layer can elicit completely different results, and this is one of the issues addressed in this work. First of all, we show that it is possible to keep human intestinal mucosa in polarized culture for at least 24 hours, provided the explants are cultured in an atmosphere that is rich in oxygen. Polarized challenge is achieved by mechanical means, namely by attaching a cave plastic cylinder on the apical side of the mucosal layer, in order to confine the stimuli. We examine the impact of the cylinder and the surgical glue used to attach it on tissue morphology and survival, and show that there is no negative impact. Once optimized, this experimental set-up is used to challenge explants with pathogenic and probiotic bacteria alike and evaluate the immune response. On this model we are able to mimic a classical pathogen infection using a highly invasive Salmonella enterica serovar typhimurium strain, FB62. The response of the tissue to the pathogen was monitored by assessing the phenotype of explants after culture, while cytoine secretion profiles of the tissue were also studied. Salmonella challenge led to a damaged explant phenotype, upregulation of TNF-α and downregulation of IL-10. This response was abolished in the presence of an antiinflammatory postbiotic component, namely culture supernatant of the probiotic Lactobacillus paracasei. Moreover, as far as challenge with pathogens is concerned, we use this novel system to examine the mechanism of Shigella induced apoptosis of epithelial cells. Importantly, no animal models are available for the study of Shigella infection, as these 18 bacteria are poorly virulent in rodents. Thus, in an effort to study the involvement of Gadd45a in the apoptotic route triggered by Shigella on intestinal epitelial cells, HeLa cells, which are however a poor model for an intestinal pathogen were used. Gadd45a participates in the responses to a variety of DNA damaging agents and interacts with proteins such as Cdc2, PCNA and p21. In this work, the authors showed that after infection of HeLa cells with Shigella, Gadd45a is involved in the induction of the apoptotic process. The data was confirmed in a more relevant setting, by applying Shigella on human intestinal mucosa. Finally, we use the novel organ culture platform to test three different strains thought to exert probiotic actions. Surprisingly, we show that this is not the case, and the three strains can exert different activities even on healthy tissue. More specifically, Lactobacillus paracasei and Lactobacillus rhamnosus GG did not significantly alter the phenotype or cytokine secretion profiles of healthy explants, but challenge with Lactobacillus plantarum resulted in a detrimental effect. Of note, all three strains were detrimental for IBD explants when administered as live bacteria, even though one of the strains (L. paracasei) had previously been found to exert a prophylactic effect in a mouse model of colitis. On the contrary, we show that a potent postbiotic (L. paracasei culture supernatant) is able to ameliorate overt inflammation on both ulcerative colitis and Crohn's disease tissues as attested by cytokine secretion profiles of challenged explants. In conclusion, this work introduces a valid alternative system on which to study the interaction of various components (bacterial, pharmacological, and others) with the human intestinal mucosa.

Les malalties cardiovasculars (MCVs) són la principal causa de mort al mon, juntament amb les malalties cardiometabòliques (MCM). L’objectiu principal és avaluar els efectes dels probiòtics i postbiòtics, consumits sols o amb altres compostos bioactius, en forma de càpsula/pols o afegits a matrius alimentàries, sobre els factors de risc de MCMs, particularment l’obesitat. A més, dilucidar possibles mecanismes d’acció, revelar nous biomarcadors d’obesitat i determinar possibles associacions de la microbiota intestinal amb la ingesta dietètica i paràmetres clínics. Es van realitzar cinc estudis: una revisió sistemàtica i metaanàlisi i una revisió narrativa per integrar la literatura disponible sobre la relació i l'eficàcia dels probiòtics i productes lactis fermentats (PLF) sobre els factors de risc MCM; dos estudis d’intervenció nutricional en subjectes amb obesitat abdominal que van consumir Bifidobacterium animalis subsp. lactis CECT 8145 (Ba8145) per avaluar els efectes sobre els factors de risc de MCM i la microbiota intestinal; un estudi transversal amb subjectes prims i amb sobrepès/obesitat per diferenciar la microbiota intestinal i determinar associacions amb variables clíniques i la ingesta dietètica. En conclusió, el consum regular de PLF redueix el risc de MCM i la suplementació amb probiòtics millora els factors de risc de MCM. El Ba8145 consumit com a probiòtic o postbiòtic redueix els marcadors antropomètrics d’adipositat. El postbiòtic Ba8145 va millorar paràmetres glucèmics, la pressió arterial diastòlica i pressió del pols. Els efectes beneficiosos del Ba8145 es podrien explicar parcialment per canvis en la microbiota intestinal. A més, l’anàlisi metagenòmic va mostrar possibles biomarcadors d’obesitat i noves associacions entre la microbiota intestinal amb la ingesta dietètica i els paràmetres clínics. L’addició de probiòtics o postbiòtics a les estratègies dietètiques actuals podria conduir a noves perspectives pel que fa al maneig de les MCM en humans amb almenys un factor de risc de MCM.
Las enfermedades cardiovasculares (ECV) son la principal causa de muerte en el mundo, junto con las enfermedades cardiometabólicas (ECM). El objetivo principal es evaluar los efectos de los probióticos y postbióticos, consumidos solos o con otros compuestos bioactivos, en forma de cápsulas/polvo o añadidos a matrices alimenticias sobre los factores de riesgo de ECM, particularmente la obesidad. Además, dilucidar posibles mecanismos de acción, revelar nuevos biomarcadores de obesidad y determinar posibles asociaciones de la microbiota intestinal con la ingesta dietética y parámetros clínicos. Se realizaron cinco estudios: una revisión sistemática y metaanálisis y una revisión narrativa para integrar toda la literatura disponible sobre la relación y efectividad de los probióticos y productos lácteos fermentados (PLF) en los factores de riesgo de ECM; dos estudios de intervención nutricional en sujetos con obesidad abdominal que consumieron Bifidobacterium animalis subsp. lactis CECT 8145 (Ba8145) para evaluar los efectos sobre factores de riesgo de ECM y sobre la microbiota intestinal; un estudio transversal con sujetos delgados y con sobrepeso/obesidad para diferenciar la microbiota intestinal y determinar asociaciones con variables clínicas y ingesta dietética. En conclusión, el consumo regular de PLF reduce el riesgo de ECM, y la suplementación con probióticos mejora los factores de riesgo de ECM. El Ba8145 consumido como probiótico o postbiótico reduce los biomarcadores antropométricos de adiposidad. El postbiótico Ba8145 tuvo efectos beneficiosos sobre los parámetros glucémicos, presión arterial diastólica y presión del pulso. Los efectos beneficiosos del Ba8145 podrían explicarse parcialmente por cambios en la microbiota intestinal. Además, el análisis metagenómico mostró posibles biomarcadores de obesidad y nuevas asociaciones entre la microbiota intestinal con la ingesta dietética y parámetros clínicos. La adición de probióticos o postbióticos a las estrategias dietéticas actuales podría conducir a nuevas perspectivas para el manejo de las CMD en humanos con al menos un factor de riesgo de ECM.
Cardiovascular diseases (CVDs) are the leading cause of death globally, along with cardiometabolic diseases (CMDs). The main objective is to evaluate the effects of probiotics and postbiotics, consumed alone or with other bioactive compounds, and consumed in capsule/powder form or added into dietary matrices, on CMD risk factors, particularly obesity. Moreover, to elucidate possible mechanisms of action, reveal new obesity biomarkers and determine possible associations of the gut microbiota with dietary intake and clinical parameters. Five studies were carried out: a systematic review and meta-analysis and a narrative review to integrated all the available literature on the relationship and effectiveness of probiotics and fermented dairy products on CMDs risk factors; two randomized controlled trials in subjects with abdominal obesity who consumed Bifidobacterium animalis subsp. lactis CECT 8145 (Ba8145) to assess the effects on CMD risk factors and on the gut microbiota; a cross-sectional study with lean and overweight/obese subjects to differentiate gut microbiota and to determine its association with clinical variables and dietary intake. Therefore, the regular consumption of fermented dairy products is associated with a reduced risk of CMDs, and probiotic supplementation improves CMD risk factors. Ba8145 consumed as a probiotic or postbiotic reduces anthropometric adiposity biomarkers. Postbiotic Ba8145 had beneficial effects on glycemic parameters, diastolic blood pressure and pulse pressure. Beneficial effects of Ba8145 could be partially explained by changes in the gut microbiota. Furthermore, the metagenomic analysis showed possible obesity biomarkers, and new associations between gut microbiota with dietary intake and clinical parameters. The addition of probiotic or postbiotic consumption to the current recommended dietary strategies could lead to new perspectives regarding the management of CMDs in humans with at least one CMD risk factor.

Inflammatory bowel disorders – such as Inflammatory Bowel Disease (IBD) – are rising worldwide. A well-known feature of IBD is dysbiosis of the gut microbiota, characterized by a significant reduction of beneficial strains and a sharp increase in facultative anaerobes, as is the case of Adherent Invasive E. coli (AIEC). Even though the implication of the microbiota in persistent inflammation has been studied for years, a direct causal relationship between dysbiosis and IBD has not been established. To date, several strategies, such as the use of probiotics, have been proposed to counteract the microbial imbalance. Nevertheless, probiotics are thought to impair the return of the indigenous microbiome, and to aggravate inflammation in immune compromised patients. Recently, postbiotics – bacterial-free metabolites secreted by probiotic strains – have been proposed as a better and safer strategy to counterbalance the effects of intestinal inflammation. The intestinal epithelium is the first layer the luminal bacteria interact with. It is composed by a thin monolayer of cells that form a protective barrier against potential detrimental antigens along the whole gut. Thus, the study of epithelial responses to bacteria or their derived metabolites is of great importance to understand intestinal health and disease. Recent advances in the use of primary epithelial cell culture using freshly isolated human intestinal crypts as starting material offers a more faithful representation of the human gut compared to immortalized cell lines. In the first study of this thesis, we describe for the first time the use of a primary epithelial bidimensional (2D) model derived from 3D organoid cultures as a successful tool to study AIEC infection and its effects on the host epithelium at early and extended infection periods. We proved that this ex vivo culture adopts an appropriate cell polarization and orientation, thus becoming a promising resource to study the interactions of the luminal content with host epithelial cells. Importantly, we showed a strain and time-specific response of primary human intestinal epithelial cells when infected with AIEC and non-AIEC strains thus supporting the use of our system to study the functional consequences of AIEC infection on the intestinal epithelium. This 2D primary cell culture system derived from intestinal organoids was also employed in the second part of this thesis to explore the putative beneficial properties of postbiotics in the epithelial response to inflammatory stimuli. Transcriptomic analysis of 2D cultures pre- treated with postbiotics points towards an effect of the metabolite-cocktail in reverting the inflammatory status of the intestinal epithelium. Moreover, postbiotics induced the differential expression of several genes on intact primary epithelial cells, demonstrating their potential in contributing to maintenance of homeostasis. Overall, the human primary organoid-derived monolayer provides a promising tool for elucidating the potentially detrimental or beneficial mechanisms underlying the crosstalk of bacteria and its metabolites with the intestinal epithelium. Moreover, the capacity of this culture to respond and mimic the pro-inflammatory environment in vitro, may expand its use in modeling bacteria-host interactions in the context of intestinal inflammatory disorders, such as IBD.
Los trastornos inflamatorios intestinales, como la enfermedad inflamatoria intestinal (EII), están aumentando en todo el mundo. Un rasgo muy conocido de la EII es la disbiosis de la microbiota intestinal, caracterizada por una reducción significativa de las cepas beneficiosas y un fuerte aumento de los anaerobios facultativos, como es el caso de la E. coli Adherente Invasiva (AIEC). Aunque la implicación de la microbiota en la inflamación persistente se ha estudiado durante años, no se ha establecido una relación causal directa entre la disbiosis y la EII. Hasta la fecha, se han propuesto varias estrategias, como el uso de probióticos, para contrarrestar el desbalance microbiano. Sin embargo, se cree que los probióticos perjudican el retorno del microbioma autóctono y pueden agravar la inflamación en los pacientes inmunocomprometidos. Recientemente, los postbióticos – metabolitos libres de bacterias secretados por cepas probióticas – se han propuesto como una mejor y más segura estrategia para mitigar los efectos de la inflamación intestinal. El epitelio intestinal es la primera capa con la que interactúan las bacterias del lumen intestinal. Éste está compuesto por una fina monocapa de células que forman una barrera protectora, a lo largo de todo el intestino, contra posibles antígenos perjudiciales. Por ello, el estudio de las respuestas del epitelio a las bacterias o a sus metabolitos es de gran importancia para comprender la función intestinal en un estado tanto saludable como de inflamación. Los recientes avances en el uso de cultivos primarios de células epiteliales utilizando células derivadas de criptas intestinales humanas como material de partida, ofrecen una representación más fiel del intestino humano en comparación con las líneas celulares inmortalizadas. En el primer estudio de esta tesis, describimos por primera vez el uso de un modelo de epitelio intestinal en conformación bidimensional (2D) derivado de organoides intestinales como herramienta para estudiar la infección por AIEC así como sus efectos en el epitelio del huésped en períodos de infección tempranos y prolongados. Demostramos que este cultivo ex vivo adopta una polarización y orientación celular adecuadas, convirtiéndose así en un recurso prometedor para estudiar las interacciones del contenido del lumen intestinal con las células epiteliales del huésped. Es importante destacar que mostramos una respuesta de las células epiteliales primarias del intestino humano que es específica de la cepa empleada (AIEC o no-AIEC) y del tiempo de infección. Estos resultados dan soporte al uso de nuestro sistema para estudiar las consecuencias funcionales de la infección por AIEC en el epitelio intestinal. Este sistema de cultivo celular primario 2D derivado de organoides intestinales también se empleó en la segunda parte de esta tesis para explorar las supuestas propiedades beneficiosas de los postbióticos en la respuesta del epitelio a varios estímulos inflamatorios. El análisis transcriptómico de los cultivos 2D pre-tratados con postbióticos apunta a un efecto del cóctel de metabolitos en la reversión del estado inflamatorio del epitelio intestinal. Además, los postbióticos indujeron la expresión diferencial de varios genes en las células epiteliales primarias intactas, demostrando su potencial para contribuir al mantenimiento de la homeostasis intestinal. En general, el cultivo primario en monocapa derivado de organoides humanos constituye una herramienta prometedora para dilucidar los mecanismos potencialmente perjudiciales o beneficiosos que subyacen a la interacción de las bacterias y sus metabolitos con el epitelio intestinal. Además, la capacidad de este cultivo para responder y simular el entorno pro- inflamatorio in vitro, puede ampliar su uso en la modelización de las interacciones bacteria- huésped en el contexto de los trastornos inflamatorios intestinales, como la EII.
Els trastorns inflamatoris intestinals, com la malaltia inflamatòria intestinal (MII), estan augmentant a tot el món. Un tret molt conegut de la MII és la disbiosis de la microbiota intestinal, caracteritzada per una reducció significativa de les soques beneficioses i un fort augment dels anaerobis facultatius, com és el cas de l'E. coli Adherent Invasiva (AIEC). Encara que la implicació de la microbiota en la inflamació persistent s'ha estudiat durant anys, no s'ha establert una relació causal directa entre la disbiosis i la MII. Fins avui, diverses estratègies tals com l'ús de probiòtics, han estat proposades per intentar contrarestar el desequilibri microbià. No obstant això, es creu que els probiòtics perjudiquen el retorn del microbioma autòcton i agreugen la inflamació en els pacients immuno-compromesos. Recentment, els postbiòtics – metabòlits lliures de bacteris secretats per soques probiòtiques – s'han proposat com una millor i més segura estratègia per a mitigar els efectes de la inflamació intestinal. L'epiteli intestinal és la primera capa amb la qual interactuen els bacteris de la llum intestinal. Aquest està composat per una fina monocapa de cèl·lules que formen una barrera protectora al llarg de tot l'intestí contra possibles antígens perjudicials. Per això, l'estudi de les respostes de l'epiteli als bacteris o als seus metabòlits és de gran importància per a comprendre la funció intestinal en un estat tant saludable com d’inflamació. Els recents avanços en el cultiu primari de cèl·lules epitelials utilitzant criptes intestinals humanes com a material de partida, ofereixen una representació més fidel de l'intestí humà en comparació amb les línies cel·lulars immortalitzades. En el primer estudi d'aquesta tesi, descrivim per primera vegada l'ús d'un model d'epiteli intestinal en conformació bidimensional (2D) derivat d’organoides intestinals com a eina per a estudiar la infecció per AIEC així com els seus efectes en l'epiteli de l'hoste en períodes d'infecció curts i prolongats. Demostrem que aquest cultiu ex vivo adopta una polarització i orientació cel·lular adequades, convertint-se així en un recurs prometedor per a l’estudi de les interaccions del contingut de la llum intestinal amb les cèl·lules epitelials de l'hoste. És important destacar que vam demostrar una resposta de les cèl·lules epitelials primàries de l'intestí humà específica de la soca emprada (AIEC o no-AIEC) i del temps d'infecció. Aquests resultats donen suport a l'ús del nostre sistema per estudiar les conseqüències funcionals de la infecció per AIEC en l'epiteli intestinal. Aquest sistema de cultiu cel·lular primari 2D derivat d’organoides intestinals també es va emprar en la segona part d'aquesta tesi per tal d’explorar les suposades propietats beneficioses dels postbiòtics en la resposta de l'epiteli a diversos estímuls inflamatoris. L'anàlisi transcriptòmic dels cultius 2D pre-tractats amb postbiòtics apunta a un efecte del còctel de metabòlits en la reversió de l'estat inflamatori de l'epiteli intestinal. A més, els postbiòtics van induir l'expressió diferencial de diversos gens en les cèl·lules epitelials primàries intactes, demostrant el seu potencial per a contribuir al manteniment de l'homeòstasi. En general, el cultiu primari en monocapa derivat d’organoides humans constitueix una eina prometedora per a dilucidar els mecanismes potencialment perjudicials o beneficiosos subjacents a la interacció dels bacteris i els seus metabòlits amb l'epiteli intestinal. A més, la capacitat d'aquest cultiu per a respondre i simular l'entorn pro-inflamatori in vitro, pot ampliar el seu ús en la modelització de les interaccions bacteri-hoste en el context dels trastorns inflamatoris intestinals, com la MII.