Telomere dynamics and cellular senescence: an emerging field in environmental and occupational toxicology.
Level 5 - mechanism / opinion, no new human data
Narrative review synthesizing epidemiological, animal, and in vitro toxicology literature
PubMed 30570381 · doi:10.1080/10408444.2018.1538201
What was done
This narrative review synthesized human epidemiological, animal, and in vitro cell culture studies examining the impact of environmental and occupational exposures (including persistent organic pollutants, heavy metals such as cadmium, arsenic, and lead, ionizing radiation, and air pollution) on telomere length, telomerase activity, and cellular senescence.
What was found
The abstract reports no quantitative figures or pooled effect sizes. Qualitatively: - Epidemiological studies showed positive associations between persistent organic pollutants and telomere length, inverse associations with cadmium, inconsistent results for arsenic and lead, a bell-shaped dose-response for ionizing radiation with shortening at low doses, and telomere shortening with long-term air pollution (short-term studies were mixed). - In vitro studies of persistent organic pollutants showed telomere shortening, reduced telomerase activity, and increased senescence. Ionizing radiation increased telomerase activity and senescence with mixed telomere length effects. Cell studies on heavy metals and air pollution particles were inconsistent. - Across experimental studies, no coherent relationship was found linking exposure, oxidative stress, telomere dynamics, and cellular senescence.
Why it matters
This review highlights telomere biology and cellular senescence as emerging endpoints in toxicology, emphasizing that disparate results across study designs necessitate standardized assay guidelines and dosing protocols.
Limits
The abstract reports no quantitative data or formal meta-analytic pooling. The underlying human literature is observational, experimental findings vary substantially by model type and dose duration, and there is a notable scarcity of animal studies evaluating telomere dynamics in target tissues.
Cited by
- partial Heavy metal exposure to cadmium and lead is associated with shorter telomeres in a dose-response manner.