MBTPS1 and Alzheimer disease: As another example, we have not studied in detail the other two S1P species we measured (d17:1, d18:0) when they did not show significant alterations at the univariate analyses stage (see Table 2, Fig. 1b, c), but their potential interactions with d16:1 and d18:1 cannot be ruled out, and further studies are required to carefully delineate the potential roles of d17:1, d18:0, d20:1, and multiple other S1P species in AD and VCI.