Astrocytic Redox Homeostasis as a Metabolic Modulator of DNA Damage and Repair in the Ischemic Penumbra.

Ischemic stroke triggers a severe redox disequilibrium that critically shapes cell survival within the penumbra. Although oxidative DNA damage arises from excessive ROS production, the capacity to repair such lesions is tightly constrained by cellular metabolic status. Growing evidence indicates that astrocytes, key metabolic regulators of the neurovascular unit, modulate neuronal susceptibility to genomic injury through redox buffering, NAD+ maintenance, and metabolic support. In the metabolically impaired yet structurally preserved penumbra, astrocytic control of glutathione turnover, mitochondrial function, and lactate shuttling may determine whether oxidative DNA lesions are efficiently repaired or progress toward energetic collapse. Poly(ADP-ribose) polymerase 1 activation following DNA strand breaks couples genomic stress to NAD+ depletion and bioenergetic failure, forming a critical interface between redox biology and metabolism. This framework posits that astrocytes preserve genomic integrity not by directly altering DNA repair pathways but by sustaining the energetic capacity required for an effective DNA damage response. Elucidating this astrocyte-centered redox-metabolic axis may reveal therapeutic strategies to stabilize penumbral tissue and improve stroke outcomes.