Role of Telomere Length in Radiation Response of Hematopoietic Stem & Progenitor Cells in Newborns.

ABSTRACT

OBJECTIVE: Wide inter-individual variations in ionizing radiation (IR) responses of neonatal hematopoietic system calls for identifying reliable biomarkers to effectively estimate radiation exposure damages in neonates. METHODS: Association between telomere length (TL) at birth and radiation sensitivity of cord blood hematopoietic stem cells (HSC) from 166 healthy newborns were investigated by assessing their clonogenic differentiation. TL was determined as terminal restriction fragment (TRF) by Southern blot method. RESULTS: TL correlated with surviving fractions of total progenitor colony forming cell (CFC) content at 0.75 Gy (p < 0.05), granulo-macrophagic lineage colony forming units (CFU-GM) at 0.75 Gy (p < 0.05) and erythroid burst forming unit (BFU-E) at 0.75 Gy (p < 0.05) & at 3 Gy (p < 0.05) of newborns. CONCLUSION: Our results indicate risks for HSC clonogenic survival in neonates with shorter telomeres after IR exposure. These observations might aid in considering TL at birth as an assessment factor for radiation related hematopoietic challenges in children.