Epigenetic aging upon allogeneic transplantation: the hematopoietic niche does not affect age-associated DNA methylation

Aging is associated with highly reproducible DNA methylation (DNAm) changes at specific sites in the genome. These age-associated DNAm changes represent a biomarker to estimate the chronological age in blood samples. It has been proposed that the microenvironment, the so called ‘stem cell niche’, has major impact on declining stem cell function in the elderly individuals. Therefore, we anticipated that after allogeneic hematopoietic stem cell transplantation (HSCT)—particularly from a young donor to an elderly patient—the estimated epigenetic age adapts to the chronological age of the patient owing to impact of the hematopoietic microenvironment.