Abstract
RATIONALE: Leukocyte telomere length (LTL) is a biological marker of aging, and shorter LTL is associated with adverse cardiovascular outcomes. Reduced regenerative capacity has been proposed as a mechanism. Bone marrow-derived circulating progenitor cells are involved in tissue repair and regeneration. OBJECTIVE: Main objective of this study was to examine the relationship between LTL and progenitor cells and their impact on adverse cardiovascular outcomes. METHODS AND RESULTS: We measured LTL by quantitative polymerase chain reaction in 566 outpatients (age: 63±9 years; 76% men) with coronary artery disease. Circulating progenitor cells were enumerated by flow cytometry. After adjustment for age, sex, race, body mass index, smoking status, and previous myocardial infarction, a shorter LTL was associated with a lower CD34(+) cell count: for each 10% shorter LTL, CD34(+) levels were 5.2% lower (P<0.001). After adjustment for the aforementioned factors, both short LTL (