Carotenoid levels in human lymphocytes, measured by Raman microspectroscopy

Carotenoid levels in lymphocytes obtained from peripheral blood of healthy people have been investigated by Raman microspectroscopy. We observed that carotenoids are concentrated in so-called “Gall bodies”. The level of carotenoids in living human lymphocytes was found to be age-dependent and to decrease with age. We performed carotenoid uptake experiments using liposomes containing beta-carotene (egg phosphatidylcholine and egg phosphatidylglycerol, 10/1 molar ratio). We observed that beta-carotene is rapidly taken up in vitro, and transported to the Gall body. From these findings we conclude that Raman microspectroscopy is a sensitive method to determine carotenoid levels in single living cells.