APOE and Hypertension: The saturation point of Xe in water without a cage vehicle for encapsulation of xenon was 0.22 mM; when the cage molecule 2-hydroxypropyl-β-cyclodextrin (HPCD) was added, Xe solubility increased from 0.22 to 0.67 mM; supplement of this Xe-enriched solutions by gavage improved hypertension and left ventricular hypertrophy and dysfunction in aged apolipoprotein E (ApoE)-knockout mice fed high-fat diet (HFD) for 6 weeks (157).