January 9, 2012

expert reaction to research on telomere length predicting lifespan in zebra finches, as published in PNAS

A new study connected the length of telomeres (lengths of DNA at the ends of chromosomes) with lifespan in zebra finches.

Prof Tom Kirkwood, Associate Dean for Ageing, Newcastle University, said:

“This excellent study shows that in zebra finches telomere length measured in chicks at 25 days old is a good predictor of subsequent lifespan. There has been a lot of interest recently in the link between telomere erosion and ageing, so it is very welcome to have such high quality data collected across the life course.

“Good as the data are, however, they still leave big questions unanswered. The team found that the link between telomere length and subsequent longevity got weaker as the birds aged, being much reduced at one year old. This rather calls into question the validity of their suggestion that telomere length early in life might be ‘more important in predicting lifespan because it has more of an effect on subsequent tissue function’. If, as much previous research has suggested, damage to tissue function occurs only as the telomeres become critically short, the link between telomere length and future survival should be just as apparent at one year of age and beyond. In terms of cell proliferation, and hence the capacity for telomeres to get shorter, 25 days is already quite old.

“It would therefore be really interesting to know if during the early development of the chicks there hasn’t been some other kind of varying biological stress causing both the differences in telomere length and in the long-term prospects for survival. It might be that the shorter telomeres in in some of the young chicks are simply a sign of something else that is bad having occurred.”

Dr Duncan Baird, Reader, School of Medicine, Cardiff University, said:

“Telomere length provides a marker of cellular ageing and telomere dysfunction might play a role in the ageing process itself. This new study, in a well-controlled, short lived bird species, provides a nice demonstration of how telomere length at a specific developmental stage can predict longevity. However translating this information into the long-lived and heterogeneous human population will be considerably more challenging.”

‘Telomere length in early life predicts lifespan’ by Britt Heidinger et al., published in Proceedings of the National Academy of Sciences on Monday 9th January 2012.