Standardization and quality assessment for human intestinal organoids

Advanced Animal Replacement Testing Strategies Using Stem Cell and Organoids

The increasing ethical concerns and regulatory restrictions surrounding animal testing have accelerated the development of advanced in vitro models that more accurately replicate human physiology. Among these, stem cell-based systems and organoids have emerged as revolutionary tools, providing ethical, scalable, and physiologically relevant alternatives. This review explores the key trends and driving factors behind the adoption of these models, such as technological advancements, the principles of the 3Rs (Replacement, Reduction, and Refinement), and growing regulatory support from agencies like the OECD and FDA. It also delves into the development and application of various model systems, including 3D reconstructed tissues, induced pluripotent stem cell-derived cells, and microphysiological systems, highlighting their potential to replace animal models in toxicity evaluation, disease modeling, and drug development. A critical aspect of implementing these models is ensuring robust quality control protocols to enhance reproducibility and standardization, which is necessary for gaining regulatory acceptance. Additionally, we discuss advanced strategies for assessing toxicity and efficacy, focusing on organ-specific evaluation methods and applications in diverse fields such as pharmaceuticals, cosmetics, and food safety. Despite existing challenges related to scalability, standardization, and regulatory alignment, these innovative models represent a transformative step towards reducing animal use and improving the relevance and reliability of preclinical testing outcomes.

Intestinal organoids in inflammatory bowel disease: advances, applications, and future directions

Inflammatory bowel disease (IBD), characterized by chronic gastrointestinal inflammation, is a significant global health challenge. Traditional models often fail to accurately reflect human pathophysiology, leading to suboptimal treatments. This review provides an overview of recent advancements in intestinal organoid technology and its role in IBD research. Organoids, derived from patient-specific or pluripotent stem cells, retain the genetic, epigenetic, and structural characteristics of the native gut, allowing for precise modeling of key aspects of IBD. Innovations in CRISPR editing, organoid-microbe co-cultures, and organ-on-a-chip systems have enhanced the physiological relevance of these models, facilitating drug discovery and personalized therapy screening. However, challenges such as vascularization deficits and the need for standardized protocols remain. This review underscores the need for interdisciplinary efforts to bridge the gap between models and the complex reality of IBD. Future directions include the development of scalable vascularized models and robust regulatory frameworks to accelerate therapeutic translation. Organoids hold promise for unraveling IBD heterogeneity and transforming disease management.

Biomimetic culture substrates for modelling homeostatic intestinal epithelium in vitro

The increasing interest in utilizing three-dimensional (3D) in vitro models with innovative biomaterials to engineer functional tissues arises from the limitations of conventional cell culture methods in accurately reproducing the complex physiological conditions of living organisms. This study presents a strategy for replicating the intricate microenvironment of the intestine by cultivating intestinal cells within bioinspired 3D interfaces that recapitulate the villus-crypt architecture and 3D tissue arrangement of the intestine. Intestinal cells cultured on these biomimetic substrates exhibited phenotypes and differentiation characteristics resembling intestinal-specific cell types, effectively replicating intestinal tissue. Notably, tissue proliferation and differentiation were achieved within 72-120 h-significantly faster than the several weeks required by conventional bioengineered materials, which often pose risks of tissue necrosis or cross-contamination. Additionally, the differentiated cells on these villi-crypts mimicking bio-interfaces exhibit higher production of natural antimicrobial peptides, resulting in reduced pathogenic infection compared to control samples. Furthermore, our method stands out for simplicity in fabrication, eliminating the need for cleanroom procedures and complex microfabrication techniques.

Colorectal Organoids: Models, Imaging, Omics, Therapy, Immunology, and Ethics

Colorectal epithelium was the first long-term 3D organoid culture established in vitro. Identification of the key components essential for the long-term survival of the stem cell niche allowed an indefinite propagation of these cultures and the modulation of their differentiation into various lineages of mature intestinal epithelial cells. While these methods were eventually adapted to establish organoids from different organs, colorectal organoids remain a pioneering model for the development of new applications in health and disease. Several basic and applicative aspects of organoid culture, modeling, monitoring and testing are analyzed in this review. We also tackle the ethical problems of biobanking and distribution of these precious research tools, frequently confined in the laboratory of origin or condemned to destruction at the end of the project.