Quantification of dolichol in the human lens with different types of cataracts

PURPOSE To quantify and characterize dolichol species in cataractous and clear human lenses. METHODS Whole lenses were collected from cadaver eyeballs from the C.H. Nagri Eye Bank and Red Cross Society Eye Bank (Ahmedabad, India). Cataractous nuclei were collected after extracapsular cataract extraction (ECCE). Wet weight for all the lenses was taken and were stored at -50 degrees C until used. Dolichol was extracted using a standard protocol and then analyzed using High Performance Liquid Chromatography (HPLC) on a 4.6 mmx60 mm Hypersil-Octadecylsilane (ODS; 3 microm) reversed phase column using a Waters dual pump apparatus, a Waters gradient programmer, and an ultraviolet (UV) detector set at 210 nm. Dolichol 13 was used as an internal standard, and dolichol mixture from the liver was used as an external qualitative standard. RESULTS The highest dolichol concentration was found in nuclear cataract (2.54+/-0.6 microg) followed by posterior subcapsular cataract (1.4+/-0.35 microg), and the lowest levels were observed in cortical cataract (0.37+/-0.06 microg). The level of dolichol concentration in cataractous lenses was statistically significantly higher than the levels in clear lenses (1.0+/-04.3 microg; p<0.01). CONCLUSIONS The dolichol concentration was significantly higher in lenses with nuclear cataract. A significant difference in dolichol concentration was observed between the different types of cataract. It suggests that dolichol and other isoprenoids may be associated with cataractogenesis.