Astrocyte Enrichment of 3D Cortical Constructs Enhances Brain Repair

ABSTRACT Regenerative medicine offers a promising approach to treat brain injuries, yet challenges persist in promoting neuronal survival and integration. Recent studies demonstrate that human cells implanted into rodent brains can exhibit plasticity, integrate into neural circuits and alleviate functional deficits. However, integration is often poor, with inadequate vascularization, and insufficient support cells such as astrocytes. Astrocytes play a crucial role in neuronal development and recovery by releasing growth factors, facilitating synaptogenesis, and promoting blood vessel formation. This study investigated human neuronal progenitor cells cultured alone or cultured with mouse astrocytes and formed into 3D constructs using microfluidics. Co‐cultures exhibited enhanced neuronal maturation, viability, and density. Following implantation into mouse brains, co‐cultures reduced lesion size, increased axonal growth, and improved astrocyte coupling to blood vessels within the graft. Additionally, we show that NPCs and co‐cultures increased astrocyte size in implants. Deconvolved high‐resolution microscopy identified synapses and optogenetics showed functional connections between the host and implants. These findings underscore the essential role of astrocytes in enhancing neuronal tissue integration and advancing brain injury treatments.