Définition
Telomeres are the protective caps at the ends of chromosomes, analogous to the plastic tips on shoelaces. They shorten with each cell division and are one of the primary molecular clocks of biological aging. Shorter telomeres are associated with accelerated aging.
Telomeres consist of repetitive DNA sequences (TTAGGG in humans) that protect chromosome ends from degradation and abnormal fusion. The enzyme telomerase can partially rebuild telomeres, but in most somatic cells, activity is insufficient to fully compensate for the shortening that occurs with each division.
When telomeres shorten to a critical length, cells enter senescence (permanent growth arrest) or apoptosis (programmed death). The accumulation of senescent cells in tissues drives the chronic inflammation and organ dysfunction associated with biological aging.
Telomere length is influenced by several modifiable factors: chronic psychological stress is one of the most potent accelerants (a landmark PNAS study found caregivers of chronically ill children had telomeres equivalent to women a decade older). Smoking, sedentary behavior, excess visceral adiposity, and poor diet quality consistently associate with shorter telomeres. Conversely, aerobic exercise, stress management, adequate sleep, and a Mediterranean-style diet are associated with telomere preservation and, in some studies, modest elongation. Telomere length can now be measured via commercial tests as a component of biological age assessment.
Termes associés
Ava Longevity · Built on the Ava Method · MMXXV