Human iPSC-derived CNS and retinal microvasculature-on-a-chip models recapitulate hallmarks of diabetic microvascular pathology

Abstract

The central nervous system microvasculature (CNS-mv) protects neural tissue from harmful substances while supplying oxygen, nutrients, and signaling molecules. Metabolic diseases such as diabetes induce pathological changes in these microvasculatures, leading to severe outcomes including stroke and diabetic retinopathy. Blood vessels in the brain and retina share similarities and undergo comparable pathological alterations in diabetic patients. However, mechanistic understanding of CNS-mv pathogenesis remains limited due to the lack of physiologically relevant in vitro models. Here, we developed three complementary human iPSC-derived microvascular models: (1) a CNS-mv-on-a-chip for mechanistic studies, (2) scalable 3D microvasculature drops for high-throughput screening, and (3) an inner blood-retinal barrier-on-a-chip incorporating Muller glia. All platforms self-assembled into perfusable networks with high pericyte (PC) coverage and barrier function. We identified the TNF-/NF-{kappa}B pathway as the central mediator of hyperglycemia-induced vascular damage, accompanied by robust induction of inflammatory cytokines IL-1{beta} and IL-6. Importantly, cell-type-specific analysis revealed distinct inflammatory roles: endothelial cells (ECs) predominantly activated TNF-/NF-{kappa}B downstream signaling, whereas pericytes selectively upregulated IL-1{beta}, suggesting a coordinated EC-PC inflammatory crosstalk driving vascular pathology. Functionally, both hyperglycemia and TNF-/IL-1{beta} exposure induced vascular regression, reduced PC coverage, and increased ghost vessel formation, confirming these cytokines as key effectors of diabetic microvascular damage. Uniquely, Muller glia showed divergent behavior from PCs, enhancing their perivascular sheath under inflammation - indicating reactive gliosis rather than protection. Together, these in vitro platforms provide a versatile and physiologically relevant hiPSC-based system for mechanistic studies, screening anti-inflammatory therapeutics and developing glia-targeted interventions.