Biological effects of cigarette smoke in cultured human retinal pigment epithelial cells.

The goal of the present study was to determine whether treatment
with cigarette smoke extract (CSE) induces cell loss, cellular
senescence, and extracellular matrix (ECM) synthesis in primary
human retinal pigment epithelial (RPE) cells. Primary cultured
human RPE cells were exposed to 2, 4, 8, and 12% of CSE
concentration for 24 hours. Cell loss was detected by cell
viability assay. Lipid peroxidation was assessed by loss of
cis-parinaric acid (PNA) fluorescence. Senescence-associated
ß-galactosidase (SA-ß-Gal) activity was detected by histochemical
staining. Expression of apolipoprotein J (Apo J), connective tissue
growth factor (CTGF), fibronectin, and laminin were examined by
real-time PCR, western blot, or ELISA experiments. The results
showed that exposure of cells to 12% of CSE concentration induced
cell death, while treatment of cells with 2, 4, and 8% CSE
increased lipid peroxidation. Exposure to 8% of CSE markedly
increased the number of SA-ß-Gal positive cells to up to 82%, and
the mRNA expression of Apo J, CTGF, and fibronectin by
approximately 3-4 fold. Treatment with 8% of CSE also increased the
protein expression of Apo J and CTGF and the secretion of
fibronectin and laminin. Thus, treatment with CSE can induce cell
loss, senescent changes, and ECM synthesis in primary human RPE
cells. It may be speculated that cigarette smoke could be involved
in cellular events in RPE cells as seen in age-related macular
degeneration.