SIRT1 and cardiovascular disorder: Several lncRNA–mRNA regulatory axes are involved in the action mechanisms of MSC-Exos in cardiovascular diseases, such as KLF3-AS1/sirtuin 1 (SIRT1) [13], MALAT1/autophagy-related 4a (ATG4a) [46], urothelial cancer associated 1 (UCA1)-Bcl-2 [54], and Mir9-3hg/Pum2 [55].