FAP and type 2 diabetes mellitus: At the same time, no significant differences in blood glucose levels, weight, IPGTT, and ITT were noted between the FAP KO and WT T2DM-induced HFpEF groups, indicating that FAP KO decreased FAP activity and level without altering blood glucose levels, weight, IPGTT, and ITT in T2DM-induced HFpEF mice (Figure 2b, c, d and e).