The study looked at how the hormone kisspein‑10 affects cell death in the placenta of pregnancies that go past the due date. It found that both kisspein‑10 and its receptor are higher in these placentas and that adding kisspein‑10 to placental tissue in the lab caused more cell death, especially at higher doses. The researchers think kisspein‑10 may naturally help trigger placental cell death in late or abnormal pregnancies.

Postterm pregnancy represents a condition associated with trophoblast apoptosis. Kisspeptin is a peptide able to induce apoptosis by a specific receptor, GPR54, through the upregulation of proapoptotic genes. The aims of the study were to evaluate (1) the messenger RNA (mRNA) expression of kisspeptin, GPR54, Bax/Bcl2, and p21 in postterm placentas and (2) kisspeptin ability to act on apoptosis in the third trimester placental explants. Placental specimens were collected from spontaneous term and postterm delivery and kisspeptin, GPR54, Bax/Bcl2, and p21 mRNA expression levels were analyzed by real-time polymerase chain reaction. Placental explants, collected from elective term cesarean sections, treated with different doses of kisspeptin were analyzed by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL). The expression levels of all the genes studied in postterm placentas were significantly higher than in-term placentas. Kisspeptin-induced apoptosis in placental explants with a dose-dependent effect, and TUNEL assay demonstrated the kisspeptin involvement in the apoptotic placental processes. Our present findings led us to hypothesize that kisspeptin may represent a placental proapoptotic agent acting in physiological and/or pathological pregnancy conditions in which placental apoptosis mechanisms are increased.