Hirano bodies are paracrystalline inclusions found in brains of patients with Alzheimers disease (AD), frontotemporal dementia (FTD), and in normal aged individuals. Although studies of post-mortem brain tissue provide clues of etiology, the physiological function of Hirano bodies remains unknown. A cell culture model was utilized to study the role of mutant tau proteins and model Hirano bodies. Model Hirano bodies accumulate tau in human astroglioma cells. Model Hirano bodies attenuated or enhanced cell death due to tau and the amyloid precursor protein intracellular domain (AICD) depending on the form of tau. Further, model Hirano bodies enhanced or had no effect on cell death due to tau and GSK3. These findings affirm a specific role for Hirano bodies in disease states and provides evidence that formation of Hirano bodies represents an important pathological structure in AD and FTD.