Generation and use of gastric organoids for the study of Helicobacter pylori pathogenesis

Exploring the potential of human intestinal organoids: Applications, challenges, and future directions

The complex and dynamic environment of the gastrointestinal tract shapes one of the fastest renewing tissues in the human body, the intestinal epithelium. Considering the lack of human preclinical studies, reliable models that mimic the intestinal environment are increasingly explored. Patient-derived intestinal organoids are powerful tools that recapitulate in vitro many pathophysiological features of the human intestine. In this review, the possible applications of human intestinal organoids in different research fields are highlighted. From physiologically relevant to intestinal disease modeling, regenerative medicine, and toxicology studies, the potential of intestinal organoids will be here presented and discussed. Despite the remarkable opportunities offered, limitations related to ethical concerns, tissue collection, reproducibility, and methodologies may hinder the full exploitation of this cell-based model into high throughput studies and clinical practice. Currently, distinct approaches can be used to overcome the numerous challenges found along the way and to allow the full implementation of this ground-breaking technology.

Advances in the study of gastric organoids as disease models

Gastric organoids are models created in the laboratory using stem cells and sophisticated three-dimensional cell culture techniques. These models have shown great promise in providing valuable insights into gastric physiology and advanced disease research. This review comprehensively summarizes and analyzes the research advances in culture methods and techniques for adult stem cells and induced pluripotent stem cell-derived organoids, and patient-derived organoids. The potential value of gastric organoids in studying the pathogenesis of stomach-related diseases and facilitating drug screening is initially discussed. The construction of gastric organoids involves several key steps, including cell extraction and culture, three-dimensional structure formation, and functional expression. Simulating the structure and function of the human stomach by disease modeling with gastric organoids provides a platform to study the mechanism of gastric cancer induction by Helicobacter pylori. In addition, in drug screening and development, gastric organoids can be used as a key tool to evaluate drug efficacy and toxicity in preclinical trials. They can also be used for precision medicine according to the specific conditions of patients with gastric cancer, to assess drug resistance, and to predict the possibility of adverse reactions. However, despite the impressive progress in the field of gastric organoids, there are still many unknowns that need to be addressed, especially in the field of regenerative medicine. Meanwhile, the reproducibility and consistency of organoid cultures are major challenges that must be overcome. These challenges have had a significant impact on the development of gastric organoids. Nonetheless, as technology continues to advance, we can foresee more comprehensive research in the construction of gastric organoids. Such research will provide better solutions for the treatment of stomach-related diseases and personalized medicine.

Advances towards the use of gastrointestinal tumor patient-derived organoids as a therapeutic decision-making tool

In December 2022 the US Food and Drug Administration (FDA) removed the requirement that drugs in development must undergo animal testing before clinical evaluation, a declaration that now demands the establishment and verification of ex vivo preclinical models that closely represent tumor complexity and that can predict therapeutic response. Fortunately, the emergence of patient-derived organoid (PDOs) culture has enabled the ex vivo mimicking of the pathophysiology of human tumors with the reassembly of tissue-specific features. These features include histopathological variability, molecular expression profiles, genetic and cellular heterogeneity of parental tissue, and furthermore growing evidence suggests the ability to predict patient therapeutic response. Concentrating on the highly lethal and heterogeneous gastrointestinal (GI) tumors, herein we present the state-of-the-art and the current methodology of PDOs. We highlight the potential additions, improvements and testing required to allow the ex vivo of study the tumor microenvironment, as well as offering commentary on the predictive value of clinical response to treatments such as chemotherapy and immunotherapy.

Patient-derived organoids in translational oncology and drug screening

Patient-derived organoids (PDO) are a new biomedical research model that can reconstruct phenotypic and genetic characteristics of the original tissue and are useful for research on pathogenesis and drug screening. To introduce the progression in this field, we review the key factors of constructing organoids derived from epithelial tissues and cancers, covering culture medium and matrix, morphological characteristics, genetic profiles, high-throughput drug screening, and application potential. We also discuss the co-culture system of cancer organoids with tumor microenvironment (TME) associated cells. The co-culture system is widely used in evaluating crosstalk of cancer cells with TME components, such as fibroblasts, endothelial cells, immune cells, and microorganisms. The article provides a prospective for standardized cultivation mode, automatic morphological evaluation, and drug sensitivity screening using high-throughput methods.

Toll-like Receptor 9 Pathway Mediates Schlafen+-MDSC Polarization During Helicobacter-induced Gastric Metaplasias

BACKGROUND & AIMS

A subset of myeloid-derived suppressor cells (MDSCs) that express murine Schlafen4 (SLFN4) or its human ortholog SLFN12L polarize in the Helicobacter-inflamed stomach coincident with intestinal or spasmolytic polypeptide-expressing metaplasia. We propose that individuals with a more robust response to damage-activated molecular patterns and increased Toll-like receptor 9 (TLR9) expression are predisposed to the neoplastic complications of Helicobacter infection.

METHODS

A mouse or human Transwell co-culture system composed of dendritic cells (DCs), 2-dimensional gastric epithelial monolayers, and Helicobacter were used to dissect the cellular source of interferon-α (IFNα) in the stomach by flow cytometry. Conditioned media from the co-cultures polarized primary myeloid cells. MDSC activity was determined by T-cell suppression assays. In human subjects with intestinal metaplasia or gastric cancer, the rs5743836 TLR9T>C variant was genotyped and linked to TLR9, IFNα, and SLFN12L expression by immunohistochemistry. Nuclear factor-κB binding to the TLR9 C allele was determined by electrophoretic mobility shift assays.

RESULTS

Helicobacter infection induced gastric epithelial and plasmacytoid DC expression of TLR9 and IFNα. Co-culturing primary mouse or human cells with DCs and Helicobacter induced TLR9, IFNα secretion, and SLFN⁺-MDSC polarization. Neutralizing IFNα in vivo mitigated Helicobacter-induced spasmolytic polypeptide-expressing metaplasia. The TLR9 minor C allele creates a nuclear factor-κB binding site associated with higher levels of TLR9, IFNα, and SLFN12L in Helicobacter-infected stomachs that correlated with a greater incidence of metaplasias and cancer.

CONCLUSIONS

TLR9 plays an essential role in the production of IFNα and polarization of SLFN⁺ MDSCs on Helicobacter infection. Subjects carrying the rs5743836 TLR9 minor C allele are predisposed to neoplastic complications if chronically infected.

In vitro models to evaluate ingestible devices: Present status and current trends

Orally ingestible medical devices offer significant opportunity in the diagnosis and treatment of gastrointestinal conditions. Their development necessitates the use of models that simulate the gastrointestinal environment on both a macro and micro scale. An evolution in scientific technology has enabled a wide range of in vitro, ex vivo and in vivo models to be developed that replicate the gastrointestinal tract. This review describes the landscape of the existing range of in vitro tools that are available to characterize ingestible devices. Models are presented with details on their benefits and limitations with regards to the evaluation of ingestible devices and examples of their use in the evaluation of such devices is presented where available. The multitude of models available provides a suite of tools that can be used in the evaluation of ingestible devices that should be selected on the functionality of the device and the mechanism of its function.

Modeling pancreatic pathophysiology using genome editing of adult stem cell-derived and induced pluripotent stem cell (iPSC)-derived organoids

In recent years, organoids have become a novel in vitro method to study gastrointestinal organ development, physiology, and disease. An organoid, in short, may be defined as a miniaturized organ that can be grown from adult stem cells in vitro and studied at the microscopic level. Organoids have been used in multitudes of different ways to study the physiology of different human diseases including gastrointestinal cancers such as pancreatic cancer. The development of genome editing based on the bacterial defense mechanism clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 has emerged as a laboratory tool that provides the opportunity to study the effects of specific genetic changes on organ development, physiology, and disease. The CRISPR/Cas9 approach can be combined with organoid technology including the use of induced pluripotent stem cell (iPSC)-derived and tissue-derived organoids. The goal of this review is to provide highlights on the development of organoid technology, and the use of this culture system to study the pathophysiology of specific mutations in the development of pancreatic and gastric cancers.NEW & NOTEWORTHY The goal of this review is not only to provide highlights on the development of organoid technology but also to subsequently use this information to study the pathophysiology of those specific mutations in the formation of malignant pancreatic and gastric cancer.

Gastric Metabolomics Detects Helicobacter pylori Correlated Loss of Numerous Metabolites in Both the Corpus and Antrum

Helicobacter pylori is a chronic bacterial pathogen that thrives in several regions of the stomach, causing inflammation that can vary by site and result in distinct disease outcomes. Whether the regions differ in terms of host-derived metabolites is not known. We thus characterized the regional variation of the metabolomes of mouse gastric corpus and antrum organoids and tissue. The uninfected secreted organoid metabolites differed between the corpus and antrum in only seven metabolites as follows: lactic acid, malic acid, phosphoethanolamine, alanine, uridine, glycerol, and isoleucine. Several of the secreted chemicals were depleted upon H. pylori infection in both regions, including urea, cholesterol, glutamine, fumaric acid, lactic acid, citric acid, malic acid, and multiple nonessential amino acids. These results suggest a model in which H. pylori preferentially uses carboxylic acids and amino acids in complex environments, and these are found in both the corpus and antrum. When organoid metabolites were compared to mouse tissue, there was little overlap. The tissue corpus and antrum metabolomes were distinct, including antrum-elevated 5-methoxytryptamine, lactic acid, and caprylic acid, and corpus-elevated phospholipid products. The corpus and antrum remained distinct over an 8-month infection time course. The antrum displayed no significant changes between the time points in contrast to the corpus, which exhibited metabolite changes that were consistent with stress, tissue damage, and depletion of key nutrients, such as glutamine and fructose-6-phosphate. Overall, our results suggest that the corpus and antrum have largely but not completely overlapping metabolomes that change moderately upon H. pylori infection.