Potential New Aging Model Schmidtea Mediterranea Undergoes Gradual Senescence, Experiences Accelerated Senescence at Elevated Temperature
Current model organisms for aging research, commonly C. elegans and D. melanogaster, possess significant limitations such as non-aging life stages, loss of 10-15% of genes compared to non-Ecydosozoans, and low or absent tissue repair by stem cells. An emerging model organism, Schmidtea mediterranea, does not have these limitations. This flatworm species may be a much better representation of human aging while still having the desirable traits of a simple model organism. This study characterized normal aging through demographic study illustrating that this flatworm species, from a demographic standpoint, is indeed a suitable model. A number of additional relationships were shown including the reduction of lifespan and reproductive output resulting from elevated growth temperature, and high reproductive output correlates with long life. In C. elegans a number of biomarkers for aging have been established. These biomarkers are biochemical or physiological changes that occur with age. Several putative biomarkers were tested for effectiveness in S. mediterranea but were shown to be minimally effective. Other unique methodology was developed or adapted for use in planarians such as AGE1 siRNA knockdown and the characterization of polyclonal peptide antibody raised for detection of AGE1.