Early in the research, inflammation looked like the obvious starting point. Source after source placed it at the top of the causal chain: microglia activate, inflammatory cytokines rise, neurons die. The narrative was clean and widely cited.
But the clinical trial record told a different story. The ADAPT trial testing naproxen and celecoxib in Alzheimer's prevention was halted early. The treatment group trended worse. INTREPAD, testing naproxen in at-risk populations, found no benefit. Prednisone, rofecoxib, indomethacin, tarenflurbil, ibuprofen. Every major anti-inflammatory trial in Alzheimer's either failed outright or made outcomes worse.
That pattern forced a harder question: what if the causal arrow points the other way? The ferroptosis literature provided the mechanism. When cells die by ferroptosis, they release damage-associated molecular patterns (DAMPs) such as HMGB1, ATP, and oxidized lipids, which activate the NLRP3 inflammasome and recruit inflammatory responses. Ferroptosis is more immunogenic than apoptosis. The inflammation researchers were documenting was real, but it was substantially a consequence of upstream cell death, not its cause.
This doesn't mean inflammation plays no role. The consensus recognizes a bidirectional cycle where inflammation and cell damage amplify each other. But the trial failures suggest that targeting inflammation alone can't break the cycle. The upstream driver, iron-dependent lipid peroxidation, has to be addressed first.