The role of pancreatic islet macrophages in type 2 diabetes mellitus: from underlying pathological mechanisms to therapeutic target discovery

The pathogenesis of type 2 diabetes mellitus (T2DM) is closely associated with chronic inflammation within the islet microenvironment, where pancreatic islet macrophages serve as central orchestrators of local immune regulation. This review provides a systematic overview of the ontogeny, phenotypic heterogeneity, and functional roles of pancreatic islet macrophages in T2DM pathology. Pancreatic islet macrophages contribute to β-cell proliferation and the maintenance of islet homeostasis through the secretion of various growth factors, such as platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF). Under conditions of metabolic stress, including lipotoxicity and glucotoxicity, these macrophages are polarized toward a pro-inflammatory phenotype. In this state, they impair β-cell function by releasing inflammatory mediators, including interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α). Furthermore, this article discusses potential clinical strategies that target pancreatic islet macrophages—such as anti-inflammatory agents and immunomodulators—highlighting their promise as novel perspectives for precise intervention in T2DM.