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Telomeres are protective chromosomal ends. Short telomeres are a proven biomarker of biological aging. We aimed to find an association of telomere length and telomerase activity in circulating leukocytes and thromboaspirates of patients with acute myocardial infarction. Furthermore, association of the telomere-telomerase system with oxidative stress markers (as common risk factors for coronary artery disease (CAD)) was tested.

Material and methods:
Patients were selected from the patients admitted to the intensive care unit with acute myocardial infarction with ST-segment elevation (STEMI), with the following inclusion criteria – STEMI patients between 18 and 80 years old of both genders and candidates for primary percutaneous coronary intervention, with infarction pain present for a maximum of 12 h. In all the patients leukocyte telomere length, telomerase activity and scores related to oxidative-stress status (Protective, Damage and OXY) were evaluated.

Patients were divided into different groups: with stable angina pectoris (AP) (n = 22), acute myocardial infarction with: STEMI (n = 93), non-obstructive coronary arteries (MINOCA) (n = 7), blood vessel rupture (n = 6) at three time points, and compared to the group of 84 healthy subjects. Telomerase activity was significantly higher in all CAD sub-groups compared to the control group (AP = 0.373 (0.355–0.386), STEMI = 0.375 (0.349–0.395), MINOCA = 0.391 (0.366–0.401), blood vessel rupture = 0.360 (0.352–0.385) vs. CG = 0.069 (0.061–0.081), p < 0.001), while telomeres were significantly shorter in STEMI, MINOCA and blood vessel rupture groups compared to the control group (STEMI = 1.179 (0.931–1.376), MINOCA = 1.026 (0.951–1.070), blood vessel rupture = 1.089 (0.842–1.173) vs. CG = 1.329 (1.096–1.624), p = 0.030]. Values of OXY score were significantly higher in STEMI and MINOCA patients compared to the control group and AP patients (5.83 (4.55–7.54) and 10.28 (9.19–10.72) vs. 4.94 (3.29–6.18) and 4.18 (2.58–4.86), p < 0.001). Longer telomeres and higher telomerase activity were found in thromboaspirates, compared to the peripheral blood leukocytes in the same patients (1.25 (1.01–1.84) vs. 1.18 (0.909–1.516), p = 0.036; and 0.366 (0.367–0.379) vs. 0.366 (0.367–0.379), p < 0.001, respectively). In addition, telomere length and telomerase activity had good diagnostic ability to separate STEMI patients from healthy persons.

Leukocyte telomere length and telomerase activity can differentiate CAD patients from healthy persons, and relate CAD to oxidative stress.