Age-related efficiency of Ca-DTPA to reduce 141Ce retention in rats

The study was aimed at evaluating the influence of age on the efficiency of chelation therapy for cerium in case of late administration. The efficacy of trisodium calcium diethylene-triaminepentaacetate (Ca-DTPA) administered as a first dose 48 and 72 h after 141Ce was investigated in 8-week-old and 2-week-old rats. The effect of treatment gradually decreased depending on the time period between radionuclide and chelating agent administration. Higher efficacy of chelation therapy in reducing the whole-body retention of 141Ce in older animals was constantly shown to be independent of the time of administration of chelating agent. The influence of age on the efficacy of chelation therapy was different for various organs and tissues; e.g., for liver and gut chelation therapy it was more effective in older animals, for kidneys it was equally effective in both age groups, while for bone it was more effective in the younger animals. The present results indicate that the effect of age in chelation therapy is influenced by the time of administration of the agent as well as by radionuclide distribution in organs and their availability for chelation.