Retina PUFAs

Polyunsaturated fatty acids (PUFAs) have various physiological functions and are widely used as pharmaceuticals, neutraceuticals, and as food additives. The ethyl ester of eicosapentaenoic acid (EPA) has been used for the treatment of arteriosclerosis and hyperlipemia since 1991 in Japan (Hara, 1993). DHA possesses not only similar physiological activities to those of EPA, but also an important function in the brain and retina (Hung, 2007). In addition, DHA accelerates the growth of preterm infants as does arachidonic acid (Carlson et al., 1993 Lanting et al., 1994). From these reasons, DHA ethyl ester (DHAEE) is currently expected to be used as a medicine, and the development of the purification methods is desired. 

Retina has one of the highest rates of oxygen consumption of any tissue in the body. The retina is exposed to sunhght, which can cause photooxidative stress. Photoreceptors are rich in PUFAs, which are vulnerable to ROS damage. 

The fact that such an elaborate system of DHA maintenance is in place suggests that its presence serves some important function in the retina. Otherwise, why not let the DHA levels fluctuate as a function of dietary intake On a similar issue Crawford and Sinclair (1972) found that proportions of arachidonic, docosatetraenoic, and docosahexaenoic acids in brain gray matter lipids were constant in over 30 species. In contrast, other tissues such as liver and muscle reflect species dietary intake (Crawford Sinclair, 1972). The fact that PUFAs comprise approx 7% (dry weight) of brain gray matter (Sinclair, 1975),... 

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