Objective: Telomeres are nucleoprotein structures consisted of repetitive DNA sequences, sited at the termini of the chromosomes. They stabilize the chromosomes, and protect them from fusion and degradation. Telomeres are progressively shortened with each mitotic cycle and also by environmental factors such as oxidative stress. Dysfunctional telomeres tend to form aggregates, which are end to end fusion of telomeres, independent of telomere length. The pathogenesis of preeclampsia and intrauterine growth restriction (IUGR) involves intrauterine hypoxic stress. Our aim was to compare telomeres length and aggregates formation in trophoblasts from pregnancies complicated with preeclampsia combined or not with IUGR, to uncomplicated pregnancies.
Methods: Four groups of placental biopsies from third trimester pregnancies were studied: Severe preeclampsia without IUGR, IUGR without preeclampsia, preeclampsia combined with IUGR, and a control group of uncomplicated pregnancies. Quantitative fluorescence-in-situ protocol (Q-FISH) was performed on slides prepared from paraffin embedded placental biopsies. Telomere fluorescence intensity and number as well as telomeres aggregates formation were determined manually and by computerized analysis of digital photographs.
Results: The number and intensity of telomeres staining was significantly lower in placentas from pregnancies complicated with preeclampsia, IUGR, or both, compared to controls. The number of aggregates was significantly higher in trophoblasts of preeclamptic placentas, however, not in the IUGR ones. (Main results are summarized in the table attached).
Conclusions: Telomeres are shorter in placentas from pregnancies complicated with preeclampsia or IUGR. Telomeres aggregate formation is increased in preeclampsia but not in IUGR, implying different placental stress related mechanisms in preeclampsia with or without IUGR.
Tal Biron-Shentala,e, Rivka Sukenik Halevya,e, Yudith Sharon b,c, Lilach Goldberg-Bittmanb,c, Dvora Kidronde, Moshe D. Fejginab,e, Aliza Amielbc
aDepartment of OBGYN department, Meir Medical Center, bGenetic Institute, Meir Hospital, Kfar-Saba, cFaculty of Life Science, Bar-Ilan University, Ramat Gan,
Deaprtment fo Pathology, Meir Hospital, Kfar-Saba d, Sackler School of Medicine, Tel Aviv University, Tel Aviv e.