Introduction Circulating EPCs home to sites of ischaemia and vascular injury as a repair mechanism to damaged endothelium and contribute to reendothelialization and neovascularization [34]. EPC-mediated vascular repair has been shown to be associated with nor- malization of endothelial function and restoration of blood flow at the site of injury. Indeed, numerical and functional impairment of EPCs has been linked to endothelial dysfunction [13], increased atheroscle- rotic disease risk [6] and higher cardiovascular [30] and cerebrovascular morbidity and mortality. The incidence and prevalence of cardiovascular disease and its clinical consequences increase with advancing age whereas number and function of EPCs decrease [12, 29, 41]. Physical activity increases the number of circulating EPCs, an effect that could potentially underlie exercise-related beneficial effects on cardiovascular diseases [19]. Cigarette smoking is associated with a reduced number of EPCs together with impairment of EPC functional activities. Fur- thermore the capability of EPC to differentiate to- Christian Jung Nicole Fischer Michael Fritzenwanger Hansjo ¨rg Thude Markus Ferrari Marlen Fabris Bernhard R. Brehm Dagmar Barz Hans R. Figulla Endothelial progenitor cells in adolescents: impact of overweight, age, smoking, sport and cytokines in younger age Received: 29 June 2008 Accepted: 15 September 2008 Published online: 25 November 2008 j Abstract Background and aims Endothelial progenitor cells (EPCs) are bone marrow derived pluripotent vascular progenitor cells capable to contribute to reendothelialization and neovascularization. The number of circulating EPCs has been established as a biomarker of cardiovascular risk and is known to decrease with age. We determined the number of EPCs in teenagers and evaluated the influence of traditional risk factors focusing on overweight. Methods 79 male adolescents were enrolled (age 13–17 years; 42 of normal weight: 64.1 ± 7.6 kg; 37 above the 90th BMI- percentile: 96.9 ± 20.5 kg). 41 healthy adults served as controls. EPCs were counted by flow cytometry (CD34+/)CD133/KDR). Besides tradi- tional risk factors, cholesterol, and high sensitive CRP different cytokines were determined. Results Overweight adolescents have a higher systolic blood pressure, higher hsCRP, higher HbA(1c) and lower HDL. The number of CD34-negative EPCs, but not CD34-positive EPCs is higher in overweight adolescents. The overall level of EPCs is lower in adolescents compared to adults. Conclusions Overweight in adolescents influences EPCs in early life. CD34-negative EPCs might be more sensitive to the early risk profile and may represent a biological marker of occult vascular damage. Beginning insulin resistance, endothelial damage and elevation of EPCs could indicate the higher risk for future cardiovascular disease in obese teenagers. j Key words endothelial progenitor cells – overweight – adolescents – cytokines – cardiovascular risk factors ORIGINAL PAPER Clin Res Cardiol 98:179–188 (2009) DOI 10.1007/s00392-008-0739-5 CRC 739 C. Jung, MD (&) Æ N. Fischer M. Fritzenwanger, MD Æ M. Ferrari, MD M. Fabris Æ B.R. Brehm, MD, MBA H.R. Figulla, MD Clinic of Internal Medicine I Friedrich-Schiller-University Erlanger Allee 101 07747 Jena, Germany Tel.: +49-3641/9324101 Fax: +49-3641/9324102 E-Mail: christian.jung@med.uni-jena.de C. Jung, MD Department of Cardiology Karolinska-University-Hospital Stockholm, Sweden N. Fischer Æ H. Thude, PhD Æ M. Fabris D. Barz, MD Institute for Transfusion Medicine Friedrich-Schiller-University Jena, Germany