Telomerlengdetap

Telomerlengdetap refers to the progressive shortening of telomeres, the protective nucleotide repeats at the ends of linear chromosomes, during cell division and under stress. Telomeres prevent chromosomal deterioration and end-to-end fusions. In most somatic cells, telomere shortening occurs with each cell division due to the end-replication problem, and is accelerated by DNA damage, oxidative stress, and inflammation. When telomeres reach a critically short length, cells may enter replicative senescence or undergo apoptosis, contributing to tissue aging and loss of regenerative capacity.

Telomerase, a ribonucleoprotein reverse transcriptase, can elongate telomeres by adding repeats, but its activity is low or absent in most adult cells. It is high in germ cells, stem cells, and many cancer cells. Thus telomerlengdetap is a balance between replication-driven shortening and telomere maintenance.

Clinical and epidemiological relevance: Shorter telomeres in peripheral blood cells have been associated with aging and higher risk of cardiovascular disease, diabetes, certain cancers, and mortality, but causality remains debated. Telomere length is influenced by genetics and is a biomarker rather than a sole determinant of health.

Measurement and variability: Common methods include qPCR (T/S ratio) and Southern blot for terminal restriction fragment length; single telomere length analysis provides distribution; results depend on tissue analyzed and assay conditions.

Lifestyle factors: Smoking, obesity, physical inactivity, poor diet, chronic stress, and environmental exposures are associated with faster telomere shortening, while healthy lifestyle and stress reduction may slow loss in observational studies; evidence for interventions is ongoing.