Biomarker Prediction and Immune Landscape of Angiogenesis in Inflammatory Bowel Disease: Insights from Bioinformatics and Machine Learning Approaches

Background: The pathogenesis of inflammatory bowel disease (IBD) remains poorly understood, with angiogenesis playing a crucial role in its development. This study primarily aims to identify effective biomarkers of angiogenesis in IBD and to enhance the understanding of the disease's immunological characteristics. Methods: Data sets related to IBD were sourced from the GEO database, including one set for bioinformatics analysis and machine learning, and another for external validation. Gene sets associated with angiogenesis were obtained from the MSigDB database, and IBD-related angiogenesis gene sets were identified by intersecting with the IBD data set. Support Vector Machine (SVM), Lasso regression, and Random Forest (RF) models were employed to identify marker genes. The diagnostic performance of the eigengene was evaluated using the receiver operating characteristic (ROC) curve and a diagnostic nomogram. Single-sample gene set enrichment analysis (ssGSEA) was utilized to elucidate the immune landscape, and correlation analysis was conducted to explore the relationship between eigengenes and immune infiltration. Results: The convergence of results from LASSO, Random Forest (RF), and Support Vector Machine (SVM) analyses identified three key genes: CXCL8, THY1, and COL4A2. The biological processes associated with these genes primarily involve cytokine interactions, chemotaxis, extracellular matrix-receptor interactions, and oxidative phosphorylation, among others. Immune infiltration analysis demonstrated a significant increase in 11 immune cell types within the inflammatory bowel disease (IBD) samples. Furthermore, these signature genes exhibited a strong correlation with various immune cells. Conclusions: CXCL8, THY1, and COL4A2 have been identified as reliable potential biomarkers for angiogenesis in IBD. The immune responses mediated by these biomarkers play a critical role in IBD angiogenesis through interactions with immune-infiltrating cells.