Fetal Growth Restriction is Associated with Accelerated Telomere Shortening and Increased Expression of Cell Senescence Markers in the Placenta

A hallmark of fetal growth restriction (FGR) is restricted placental development and insufficient nutrient supply to the fetus. It has previously been shown that activity levels of telomerase, the enzyme responsible for completing replication of telomeric DNA during cell division, is suppressed in FGR placenta samples as compared to control placenta samples from donors of the same gestational age. Here we examine whether telomere length maintenance is also compromised in FGR placenta samples. Southern analysis of telomere length for placenta and cord blood samples from 32 FGR and 36 control donors, ranging in gestational age from 37 to 40 weeks, revealed significantly shorter telomeres (P ≤ 0.001) in FGR placenta samples, but not cord blood samples. Furthermore, analysis of telomerase extracts, RNA and DNA placental samples from donors with and without idiopathic FGR confirmed a direct association between suppression of telomerase activity and reduced telomere length in FGR placenta. In addition, expression levels of markers of telomere-induced senescence, p21, p16 and EF-1α, were significantly elevated in FGR placenta samples (P ≤ 0.01). These observations support a direct affect of reduced telomerase activity levels on the placental pathology associated with FGR.