Interactions between cyclodextrins and cellular components: Towards greener medical applications?

Leclercq, Loïc

As the cholesterol extraction by CDs occurs usually at very high rates, CDs have been used to demonstrate the presence of dif-ferent kinetic pools of cholesterol within cells. Unfortunately, only few papers have studied the dynamics of this process on cells. For instance, the kinetics of cholesterol efflux have been examined in different cell lines such as fibroblasts [117] , human erythrocytes [122] , rat cerebellar neurons [123] , differentiated human neurons and astrocytes [124] , etc. All these results indicated that CDs induce cholesterol, sphingolipids, and phospholipids extraction from the cytoplasmic membrane typically in a range of 50-90% of the original amount. Castagne and co-workers studied the cholesterol extraction of native and modified β-CDs on endothelial cells (HUVEC) [125] . The measurement of the residual cholesterol content of cells reveals that cholesterol was extracted in a dose dependent relationship. As expected, a correlation was obtained between the cytotoxicity and the affinity for cholesterol. The affinity of CDs for cholesterol was classified in the order β-CD < HP-β-CD < Me-β-CD. Similar results are obtained with other biological membranes [117] [118] [119] [120] [121] [122] [123] [124] [125] [126] . Another typical example has been published by Steck et al. The authors investigated the cholesterol movement created by the treatment of human erythrocytes with Me-β-CD [122] . The results show that the rate of efflux is approximately three orders of magnitude higher than the cholesterol transfer from cells to synthetic vesicles. Therefore, Me-β-CDs are very efficient to extract large amounts of membrane cholesterol at a very high rate. CDs can also catalyze the exchange of cholesterol between serum lipoproteins and cells [56] .