7α-hydroxy Cholesterol-d7 is intended for use as an internal standard for the quantification of 7α-hydroxy cholesterol by GC- or LC-MS. 7α-hydroxy Cholesterol is an oxysterol and a precursor in the biosynthesis of the bile acids cholic acid and chenodeoxycholic acid.[1],[2] It is formed via the oxidation of cholesterol by cholesterol 7α-hydroxylase/CYP7A1 in rat liver microsomes.[1] 7α-hydroxy Cholesterol (40 μM) increases levels of the adhesion molecules ICAM-1, VCAM-1, and E-selectin in human umbilical vein endothelial cells (HUVECs).[3] It increases secretion of chemokine (C-C motif) ligand 2 (CCL2) and matrix metalloproteinase-9 (MMP-9) in serum-deprived THP-1 cells when used at a concentration of 5 μg/ml.[4] 7α-hydroxy Cholesterol has been found in macrophages isolated from atherosclerotic lesions in rabbits fed a high-cholesterol diet.[5]

Reference:
[1]. Mitropoulos, K.A., and Balasubramaniam, S. Cholesterol 7α-hydroxylase in rat liver microsomal preparations. Biochem. J. 128(1), 1-9 (1972).
[2]. Chiang, J.Y.L. Bile acid metabolism and signaling in liver disease and therapy. Liver Res. 1(1), 3-9 (2017).
[3]. Lemaire, S., Lizard, G., Monier, S., et al. Different patterns of IL-1β secretion, adhesion molecule expression and apoptosis induction in human endothelial cells treated with 7α-, 7β-hydroxycholesterol, or 7-ketocholesterol. FEBS Lett. 440(3), 434-439 (1998).
[4]. Kim, S.M., Kim, B.Y., Son, Y., et al. 7α-Hydroxycholesterol induces inflammation by enhancing production of chemokine (C-C motif) ligand 2. Biochem. Biophys. Res. Commun. 467(4), 879-884 (2015).
[5]. Hultén, L.M., Lindmark, H., Diczfalusy, U., et al. Oxysterols present in atherosclerotic tissue decrease the expression of lipoprotein lipase messenger RNA in human monocyte-derived macrophages. J. Clin. Invest. 97(2), 461-468 (1996).