HDAC inhibitors, including valproic acid and trichostatin A, have shown anti-inflammatory and neuroprotective effects in central nervous system models;95 however, findings from thoracic aortic aneurysm models indicate that broad HDAC inhibition may increase aneurysm susceptibility,96 cautioning against direct extrapolation. Here, HDAC9 is linked to thoracic aortic aneurysm.