Ferreira, MiguelLeal, JoséCarneiro, Madalena2017-04-172017-09-302015-10-092015-09http://hdl.handle.net/10362/20493Why, and how, organisms age and ultimately die is a key question of modern biology. Telomeres are considered molecular timekeepers determining cellular lifespans. Because telomerase expression is restricted in human somatic cells, telomeres shorten progressively, potentially acting as central instigators for the loss of tissue regenerative capacity with age. Where – in which particular tissues – and how – by which molecular mechanisms – progressive telomere erosion promotes dysfunction in aging is still not entirely understood.(...)engdoctoral thesis