Abstract 1049: Age-Related Changes of Endothelial Dysfunction and Endothelial Progenitor Cells in Patients With Chronic Heart Failure and Healthy Subjects: Effects of Exercise Training
BACKGROUND: Endothelial dysfunction (ED) and reduced numbers of endothelial progenitor cells (EPC) occur in both physiologic aging and chronic heart failure (CHF). To our knowledge it has, however, never been assessed, if disease and aging have additive effects on ED and EPCs or if beneficial effects of exercise training (ET) are diminished in old age.
METHODS: In this study we randomized 60 pts. with stable CHF (age 62.4±1.7 yrs., EF 28.3±1.7%, VO2max 13.6±2.0ml/kg*min) and 60 healthy subjects (HS) (age 60.5±2.4 yrs., EF 60±1%, VO2 max 21.1±3.1 ml/kg*min) to a training (T) or a control group (C). To detect possible aging effects we included subjects below 55 (y) and above 65 years (o). Subjects in the T-group exercised 4 times daily at 60 to 70% of VO2max for 4 wks. under supervision. At baseline and after the intervention, flow-mediated dilatation (FMD) was assessed by a high-resolution radial ultrasound. EPCs were identified by FACS as CD34/KDR+ cells.
RESULTS: As compared to young HS, old HS showed at baseline a reduced FMD (y: 17.2±1.4%; o: 12.0±1.8%; p<0.05) and a reduced EPC-number (y: 82.8±3.2 EPC/100ml blood; o: 73.7±2.9 EPC/100ml blood; p<0.05). In young and old CHF pts., FMD (y: 9.0±0.8%; o: 9.1±1.4%) and EPC-number (y: 57.2±3.9 EPC/100ml blood; o: 53.2±4.1 EPC/100ml blood) were impaired. As a result of ET, FMD improved 32±2% in old HS (p<0.05), while it remained unchanged in young training HS and C respectively. In young and old patients with CHF four weeks of ET resulted in a significant change in FMD (y: by 31±2%; p<0.05; o: by 32±3; p<0.05). EPC-numbers increased in both CHF training groups (y: +66.3±7.2%; p<0.05; o: +68.7±6.8%; p<0.05). In C no effect was detectable.
CONCLUSIONS: The present trial provides new insight into the chronobiology of cardiovascular training effects: Among HS aging is associated with the development of ED and a reduction of EPCs. In CHF both young and old patients exhibit a similar degree of ED and EPC reduction. Four weeks of ET are effective in improving ED in old HS and in all age groups of CHF pts. with an increase in EPCs in CHF pts. The training effect was not diminished among older pts. underlining the potentials of rehabilitation interventions in a patient group, where CHF is most prevalent.