Atherosclerosis and telomeres
According to WHO statistics, cardiovascular diseases annually lead to the death of 17.5 million people and occupy the first place among the causes of death worldwide. Prevention strategies based on predicting the risk of developing these diseases are currently a priority for healthcare. At the same time, it is important to develop new biomarkers that provide more accurate prediction than traditional risk factors, such as high blood cholesterol, smoking, physical inactivity and high blood pressure. Telomere length is one of the promising biomarkers, however, the results of a study conducted by scientists of the Spanish National Center for Cardiovascular Research under the leadership of Doctors Valentin Fuster and Vicente Andrés indicate that the telomere length of leukocytes circulating in the blood does not effectively predict the risk of developing cardiovascular diseases in patients who do not have the corresponding symptoms.
Telomeres are complex structures localized at the end sections of chromosomes. Their function is to maintain genome stability and cell viability. Numerous studies have demonstrated that the DNA of telomeres progressively shortens with age, which leads to the destabilization of the genome and, ultimately, to cell death, which occurs when they reach a critical length. The shortening of telomeric DNA is considered as a marker not only of aging, but also of the general state of human health, which has aroused interest in the possibility of using the telomere length of leukocytes circulating in the blood as a prognostic factor for the risk of developing cardiovascular diseases. This idea is supported by the results of epidemiological studies, according to which patients with coronary heart disease, myocardial infarction and stroke have short telomeres. However, the data available to date are inconclusive.
Approximately half of patients with cardiovascular diseases are not in the high-risk group based on the traditional prognostic factors listed above. At the same time, many people with high values of these risk factors do not develop heart disease at all. Therefore, there is a clear need for new biomarkers that allow identifying people who do not have symptoms of the disease, but who have a high risk of developing atherosclerosis and, subsequently, myocardial infarction and stroke.
The new study included 159 volunteers who participated in the clinical trial PESA (from the English. Progression of Early Subclinical Atherosclerosis – progression of early subclinical atherosclerosis). In the framework of the study, the authors analyzed the possible relationship between the average telomere length of circulating leukocytes, as well as the proportion of critically short telomeres and the presence of manifestations of subclinical atherosclerosis (before the onset of symptoms of the disease) of various vessels. To do this, they performed two- and three-dimensional ultrasound examination of the carotid and ilio-femoral arteries and abdominal aorta, as well as computed tomography to quantify the degree of calcification of the coronary arteries.
In accordance with the results of earlier studies, new data have demonstrated the existence of an association between older age and a lower value of the average length of leukocyte telomeres, as well as a more significant proportion of short telomeres (less than 3 kilobases or 3 thousand nucleotide bases). However, no associations were found between these parameters and the presence or severity of subclinical atherosclerosis in the study participants.
At the same time, the authors note that, despite the absence of such associations, the results obtained should be interpreted with great caution. They provide information only about a specific moment in a person's life and scientists have yet to determine whether the rate of atherosclerosis progression depends on the initial length of leukocyte telomeres or on the proportion of short telomeres, as well as on the rate of telomere shortening during aging. The researchers plan to get answers to these questions during the planned follow-up of the study participants.
Article by Juan M. Fernández-Alvira et al. Short Telomere Load, Telomere Length, and Subclinical Atherosclerosis http://content.onlinejacc.org/article.aspx?articleid=2524692&resultClick=24 published in The Journal of the American College of Cardiology.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of Centro Nacional de Investigaciones Cardiovasculares Carlos III: JACC: Telomere length in circulating blood cells does not predict asymptomatic atherosclerosis.
06.06.2016