From Mechanism to Medicine: Advancing In Vitro Disease Models Using Microfluidics

Abstract

Chronic inflammatory diseases are among the greatest challenges in modern healthcare. Conditions such as chronic kidney disease and inflammatory bowel disease are characterized by persistent inflammation that leads to progressive tissue damage, reduced quality of life, and substantial societal costs. Although significant advances have been made in treatment, many therapies are only partially effective and mainly aim to slow disease progression or alleviate symptoms. The development of new drugs remains challenging and expensive, partly because traditional preclinical models, including animal models and static cell culture systems, do not adequately replicate human physiology and disease mechanisms. As a result, many promising drug candidates fail during clinical development. To address these limitations, increasing attention has been directed toward advanced in vitro models that more closely mimic human biology. Organ-on-a-chip technology combines living human cells with controlled fluid flow and three-dimensional tissue structures to recreate key physiological features of human organs. This thesis explores how organ-on-a-chip technology can be used to develop more advanced models of the kidney and intestine to study inflammatory diseases by reconstructing human tissue structures, barrier function, and immune interactions in vitro. We aimed to develop in vitro models that integrate epithelial, endothelial, and immune cells under controlled conditions to better mimic physiological tissue environments. In the kidney, perfused tubular structures derived from human kidney organoids were established and shown to retain epithelial polarization, transport activity, and donor-specific characteristics. These were further developed into a model of ischemia-reperfusion injury, reproducing key features of kidney inflammation, including complement activation, cytokine signalling, and loss of epithelial barrier integrity. This model was used to evaluate complement-targeting therapy, which reduced inflammatory activation. Addition of monocytes generated an immunocompetent kidney model, enabling real-time visualization of immune cell recruitment, revealing donor-dependent differences, and demonstrating modulation of immune responses by anti-inflammatory treatment. In parallel, an immunocompetent intestine-on-a-chip model was developed using epithelial cells, mucus-producing cells, and immune cells. Important aspects of intestinal inflammation, including barrier disruption, cytokine release, and epithelial-immune interactions were established and enabled assessment of pharmacological modulation of inflammatory responses. Together, these models demonstrate that organ-on-a-chip systems can reproduce key features of human inflammatory disease in a controlled and mechanistically accessible manner. They represent a powerful and versatile approach for studying inflammatory disease mechanisms, supporting evaluation of novel therapies, and contributing to the principles of the 3Rs by reducing reliance of animal models using human-relevant in vitro systems.