Long Telomeres in the Mature Human Placenta

ObjectiveTo investigate whether telomere shortening may play a role in senescence of the placenta.Study designVillous tissue was collected from single, random sites of full-term placentas (39–41 weeks of gestation; n = 10) as well as multiple, specific sites of the same placenta (39–41 weeks of gestation; n = 5). For the latter group of placentas, samples were taken near the umbilical cord and at the periphery on both the maternal and fetal sides (a total of 4 samples per placenta). Cord blood samples were also obtained from all placental donors. Telomerase activity was assessed by the TRAP assay, and telomere length measured by Southern analysis of mean terminal restriction fragment (TRF) length.ResultsWe show for the first time that telomeres are longer (∼25% longer; P < 0.001) in placenta tissue than in cord blood from the same donor.ConclusionTelomere shortening is unlikely to have a significant role in senescence or terminal maturation of the placenta.