TeloScan® is a genetic test that measures the length of telomeres on chromosomes, that is, the protective caps at the ends of DNA strands that tend to become smaller as they age.
This test gives the Mean Telomere Length (MTL), Relative Telomere Length (T/S), and actual biological or cellular age based on telomere length as results.
Telomeres are repetitive nucleotide elements at the ends of chromosomes that protect them from the destruction and loss of genetic information. Normal diploid cells lose a portion of telomeres with each cell division. Therefore, the length of telomeres decreases over time and can somehow "predict" life expectancy. The reduction of telomere length harms the state of health of the organism and has been associated with many pathological conditions, including aging and cancer. Accurate and reliable quantification of chromosome telomere lengths is essential for many aspects of cell biology, such as chromosomal instability, DNA repair, aging, apoptosis (or cell death), various cell dysfunctions, and oncogenesis.
What are telomeres?
Telomeres are the ends of chromosomes and play a key role in protecting their integrity. They are formed from repetitive DNA sequences—well conserved evolutionarily and similar to all vertebrates (TTAGGG)—together with specific proteins (telomere-binding proteins), thus creating a structure called a telosome. The function of telomeres is to protect the chromosomal extremities from degradation, therefore ensuring the sound functionality and viability of the cells.
What is telomerase?
Telomerase is an enzyme that maintains telomeres' structure, repairs tiny telomeres, and lengthens them. Under normal conditions, telomerase is expressed in pluripotent embryonic cells and stem cells in adults. In pathological conditions, telomerase is highly expressed in cancer cells and maintains the continuous growth of these cells. Healthy normal cells produce little or no telomerase. As a result, telomeres shrink continuously after each cell division cycle until they reach a critical point in size, which triggers the onset of cell death or irreversible cell death (Hayflick limit).
Why are telomeres important?
Telomere length is the best molecular indicator of an organism's degree of aging, and therefore, measuring telomere length can be used to estimate its biological age.
Telomeres are constantly shrinking as the body ages, resulting from successive cycles of cell division during tissue regeneration and regeneration processes. This occurs in both differentiated somatic cells and undifferentiated stem cells and has been shown to significantly reduce the ability of stem cells to regenerate tissues when telomeres are significantly reduced. There is ample evidence from experimental animals that the presence of telomeres smaller than a critical point is sufficient to cause aging in the body and that therapeutic interventions have the effect of reducing the frequency of telomere shortening (e.g., by increasing the expression of the enzyme telomerase), is enough to delay aging and increase life expectancy.
Telomeres and telomerase are of great importance in cancer biology. More than 95% of cancers of all types activate telomerase to achieve their "immortality." Telomerase appears to be very important in the growth of cancerous tumors, and therapies have begun to develop that inhibit its action.
There is a lot of research showing the link between short telomeres and the risk of developing cardiovascular disease, central nervous system disease, and other diseases that occur in old age.
What is the relationship between chronological and biological age?
Not all people age at the same rate even if they are of the same chronological age. Thus, it is vital to have molecular markers that can assess the degree of aging of an organism. This information is essential so that various age-related conditions can be treated promptly and lifestyle changes (obesity, smoking, etc.) or other appropriate therapeutic measures (supplements, medications, etc.) can be applied. Telomere length is an excellent molecular indicator of the degree of aging of an organism.
What are the factors that affect the length of telomeres?
Genetic factors and lifestyle are the main factors that affect the length of telomeres and the rate at which they decrease. For example, smoking, obesity, or even psychological stress increase oxidative stress and inflammation in the body, which results in telomere shortening. Other factors, such as diet, exercise, and sleep, are essential in aging. Various therapies for telomere regeneration have been developed in recent years, based mainly on telomerase activation. Measurement of telomeres is necessary to determine the effectiveness of these treatments.
