The first abdominal aortic aneurysm organoid model replicates complex microenvironment for in vitro disease study

Background: Abdominal Aortic Aneurysm (AAA) is a critical global health issue, affecting an estimated up to 8% of men over 65, with a complex etiology involving smoking, age and gender. However, the lack of specific drug treatments underscores the need for a robust in vitro model to advance our comprehension of AAA pathophysiology and serve as an ex vivo surrogate for drug testing. Methods: This study introduces an innovative AAA patient-derived organoid (PDO) model using a non-enzymatic procedure, a Matrigel-free system, and specialized organoid culture medium, leveraging 3-dimensional (3D) cultures to replicate the disease's microenvironment. The stability of this culture system was assessed through microscopic observation, H&E staining, immunohistochemistry (IHC), viability assays, and whole-genome sequencing (WES). Additionally, we conducted pharmacological assessments to explore the effects of drug treatments on AAA PDO. Results: Our model maintains aortic morphological integrity and pathological phenotypes, incorporates the immune microenvironment (validated by IHC markers for macrophages and lymphocytes), and adjacent tissues (loose connective tissue and vegetative blood vessels). The model demonstrates remarkable stability, confirmed by consistent genetic mutation sites throughout cultivation via WES, and cell survival after five weeks in vitro via live-cell staining. Preliminary pharmacological assessments show promising efficacy, with distinct responses to 1 μM metformin, 1 μM RU.521, or 1 μM STING-IN-2 treatments for 48 h via mass spectrometry. Conclusions: The AAA organoid model, to the best of our knowledge, is the first reported abdominal aortic aneurysm PDO model, and signifies a promising step towards therapeutic treatment options for AAA, potentially complementing existing surgical approaches.