This peer-reviewed invited review recasts traumatic brain injury not as a single bruise to the head but as a system-wide disorder that ripples through the lungs, heart, kidneys, and gut. Synthesizing evidence from rodents, swine, and nonhuman primates through early human case reports, the authors examine mesenchymal stromal cell-derived extracellular vesicles, the tiny membrane-bound parcels cells shed to talk to one another. The synthesis reveals that these vesicles can quiet inflammation, blunt cell death, and coax new vessels and neurons. The authors map cargo engineering, delivery routes, and artificial intelligence-guided design while flagging the standardization gaps that still separate promise from practice.

Why do nearly all animals sleep? A new Perspective in Brain Medicine gathers evidence from neuroimaging, electrophysiology, and machine learning to propose an answer that sits above the familiar ones. The authors synthesize existing research to argue that sleep operates as a system-level resilience mechanism, stabilizing large-scale brain dynamics, curbing maladaptive over-specialization, and preserving efficient information flow. NREM and REM stages emerge as coordinated phases of repair and reconfiguration. The same logic, the authors suggest, may extend to artificial neural networks, where structured offline phases could ease catastrophic forgetting. Sleep, in this reading, is active maintenance rather than passive rest.