Epigenetic clock analysis of human fibroblasts in vitro : effects of hypoxia, donor age, and expression of hTERT and SV40 largeT.
Level 5 - mechanism / opinion, no new human data
In vitro bench research using cultured human cells.
PubMed 31113906 · doi:10.18632/aging.101955
What was done
Human fibroblasts were cultured in vitro to evaluate changes in DNA methylation (DNAm) age across cell divisions (>10 population doublings). The authors tested the effects of oxygen tension (1% hypoxia vs. 21% normoxia), donor chronological age, and expression of immortalization factors (hTERT and SV40 Large T antigen).
What was found
DNAm age increased with cell division after >10 population doublings. Progression of DNAm age was slower under hypoxia (1% oxygen) compared to normoxia (21% oxygen). The speed of cell division-associated DNAm age progression depended on the chronological age of the cell donor. Expression of hTERT did not arrest DNAm age progression in most cells, whereas SV40 Large T antigen expression produced inconsistent effects, including DNAm age rejuvenation. The abstract does not report quantitative values, effect sizes, or variance metrics.
Why it matters
This study provides mechanistic evidence that oxygen tension, donor age, and SV40 Large T-targeted pathways (such as p53) modulate the rate of mitosis-associated epigenetic clock progression in human cells.
Limits
The findings are restricted to in vitro human fibroblast models and may not reflect in vivo tissue kinetics. The abstract provides no information on donor numbers, cell sample sizes, or quantitative statistical data.
Cited by
- supports Immortalizing a cell by overexpressing TERT (telomerase reverse transcriptase) does not stop epigenetic aging, and its epigenetic age continues to increase with passaging.