Guan JZ, Maeda T, Sugano M, Oyama J, Higuchi Y, Makino N. Mol Cell Biochem. 2007 Oct;304(1-2):353-60 .
Telomeres play a role in cellular aging and they may also contribute to the genetic basis of human aging and longevity. A gradual loss of the telomeric repeat sequences has been reported in adult tissue specimens. This study determined the percentage of telomere restriction fragment in various molecular-sized regions in addition to measuring the average telomere length. Mean telomere restriction fragment (TRF) length was determined by Southern blot analysis using a longer telomeric repeat probe with higher sensitivity. A significant decrease in longer telomere fragments and a quick increase in the shortest fragments were observed, especially in male subjects. There was a tendency that the age-adjusted telomere length was longer in females than that observed in males, while males lose the telomeric sequence faster than females. These data indicated that the percentage of longer telomeres fragments decreased, while the shortest fragments increased quickly with age. In addition, the longest telomere fragments decreased and the short fragments increased with a relatively stable frequency with age. There was also a significant difference in the longest telomere fragment percentage between males and female in their 40s and 50s, whereas no difference was observed in the mean TRF length. Interestingly, the changing rate of the longest and the shortest range group of TRF percentage associated with aging seemed quite different between before and after 50-year old with a gender-related contrast. This contrast implies a drastic change around the age of 50 of unknown factors that affect telomere attrition.