Engineered porcine livers maintained critical detoxification functions when connected to the circulatory systems of four brain-dead patients through extracorporeal cross-circulation for up to 72 hours. The xenografts demonstrated effective ammonia clearance, albumin synthesis, and coagulation factor production without triggering severe immune rejection or coagulation disorders that have historically plagued xenotransplantation attempts. This represents a significant advance in bridging therapy for acute liver failure, where donor organ scarcity claims thousands of lives annually. The genetic modifications likely included knockout of porcine antigens and insertion of human complement regulatory proteins, building on established xenotransplantation protocols. While promising, several hurdles remain before clinical application. The study duration was limited, immune suppression requirements unclear, and long-term biocompatibility unassessed. The brain-dead model, though ethically sound, may not fully replicate the inflammatory environment of living patients with acute hepatic failure. Nevertheless, this proof-of-concept could revolutionize liver support systems, potentially buying critical time for transplant candidates or serving as destination therapy where human organs remain unavailable.