Fluid phase endocytosis within buccal mucosal cells of alcohol misusers

The structure of the oral mucosa is now well characterised, although studie s on oral epithelial cell function have received less attention. The aims o f this study were to see whether endocytosis could be demonstrated in cells from oral smears and, if so, to assess the effect of chronic high alcohol intake on such uptake, Buccal mucosal smears were collected from 135 patien ts (91 non- or social drinkers, and 44 patients with harmful alcohol use). Name, age, sex, and alcohol history (for alcohol problem patients) were rec orded. Cell suspensions were incubated in a solution of bovine serum albumi n (BSA)-coated fluorescently labelled latex microspheres (0.02 mu m diamete r) in Ham's F-10 culture medium for 1 h at 37 degrees C as a marker of flui d phase endocytosis. Uptake of microspheres was confirmed by confocal micro scopy, and mean endocytosed fluorescence levels determined by flow cytometr y. A repeat smear from 11 of the alcohol patients was taken 9-14 days later . Endocytosis was significantly reduced in both male (P < 0.01) and female (P < 0.01) alcohol problem patients compared to controls. Units of alcohol consumed and cigarettes smoked per day did not show a dose-response correla tion with endocytosis in the alcohol problem patients. Apparent abstinence from alcohol had no further effect on endocytic uptake at days 9-14. This s tudy shows that normal oral squamous cells removed as buccal smears readily endocytose fluorescent microspheres and that this capacity can be affected by alcohol. Chronic high alcohol intake would appear to down regulate endo cytosis in buccal cells even up to 14 days of abstinence. This may have imp lications for the pathogenesis of oral mucosal disorders in long-term users . (C) 1998 Elsevier Science Ltd. All rights reserved.