Therapeutic potentials of unicellular green alga Chlorella in advanced glycation end product (AGE)-related disorders

Reducing sugars can react non-enzymatically with amino groups of protein to form Amadori products. These early glycation products undergo further complex reaction such as rearrangement, dehydration, and condensation to become irreversibly cross-linked, heterogeneous fluorescent derivatives, termed advanced glycation end products (AGEs). The formation and accumulation of AGEs in various tissues has been known to progress at an accelerated rate under hyperglycemic conditions in diabetes. Recent understanding of this process has revealed that AGEs have been implicated in the development of many of the pathological sequelae of diabetes and aging, such as atherosclerosis and diabetic microangiopathy. Furthermore, recently, AGE-their receptor (RAGE) interaction was also involved in neurodegenerative diseases, melanoma growth, expansion and metastasis. These observations suggest that blockade of AGE formation may be a novel promising target for therapeutic intervention in these devastating AGE-related disorders. We have recently found that unicellular green alga Chlorella inhibited the formation of AGEs in vitro. Since several lines of evidence have shown anti-atherogenic effects of Chlorella on animal models, we hypothesize here that the beneficial aspects of Chlorella on atherosclerosis could be ascribed, at least in part, to its AGE inhibitory property and that Chlorella may have therapeutic potentials in treatment of patients with other AGE-related disorders such as diabetic microangiopathy and Alzheimer's disease. In this paper, we would like to propose the possible ways of testing our hypotheses. Does daily intake of Chlorella reduce the risk of the incidence and progression of diabetic vascular complications including atherosclerosis? Does Chlorella treatment prevent the development of Alzheimer's disease and/or improve the cognitive impairment of patients with this disorder? If the answers are yes, are plasma or tissue levels of AGE in these patients actually suppressed by Chlorella treatment? And, does the extent of the AGE reduction by Chlorella predict the beneficial effects of Chlorella on these disorders? These prospective studies will provide further valuable information whether blockade by Chlorella of the AGE formation could be clinically relevant.