Effects of exercise training on mobilization and functional activity of blood-derived progenitor cells in patients with acute myocardial infarction.

BACKGROUND: The aim of the present study was to determine whether regular exercise training (ET) is effective at promoting the mobilization of CPCs and improving their functional activity in patients with recently acquired myocardial infarction (STEMI). Regular physical training has been shown to improve myocardial perfusion and cardiovascular function. This may be related in part to a mobilization of bone marrow-derived circulating progenitor cells (CPCs) as well as an enhanced vascularisation. METHODS: 37 patients with STEMI were randomly assigned to an ET group or a non-ET group (controls). Two weeks after STEMI, three weeks after regular ET and three months after ET, BNP levels, exercise echocardiography and exercise spiroergometry were evaluated. The number of CD34+/CD45+ and CD133+/CD45+ CPCs was measured by flow cytometry analysis. The migration capacity of the CPCs was determined with a boyden chamber and the clonogenic capacity by CFU-assay. RESULTS: In the ET-group the number and migration capacity of CPCs increased significantly after regular exercise training. The BNP level decreased significantly from 121 +/- 94 to 75 +/- 47 pg/ml (p<0.001) after the ET period, the left ventricular ejection fraction raised in parallel at peak exercise, and the cardiorespiratory condition improved as demonstrated by an increase of VO2max (from 1641 +/- 522 to 1842 +/- 724 ml/min, p<0.02). These three effects persist till three months after the ET period. CONCLUSIONS: Regular physical activity appears to predispose the mobilization and enhanced functional activity of CPCs, a phenomenon which might lead to an improved cardiac function in patients with recently acquired acute myocardial infarction.

Endogenous plasma endothelin concentrations and coronary circulation in patients with mild dilated cardiomyopathy.

OBJECTIVE: To determine whether increased plasma concentrations of endothelin-1 (ET-1) and big endothelin (BET) play a role in the regulation of coronary circulation in patients with idiopathic dilated cardiomyopathy (IDCM). SETTING: Tertiary referral centre for cardiac diseases. PATIENTS: Fourteen patients (eight male/six female; mean (SD) age 59 (9) years) with IDCM (ejection fraction 36 (9)%) and five normotensive subjects (two male/three female; age 52 (7) years) serving as controls were studied. METHODS: Functional status was classified according to New York Heart Association (NYHA) class. Endogenous ET-1 and BET plasma concentrations from the aorta and the coronary sinus were determined by radioimmunoassay. Coronary blood flow, using the inert chromatographic argon method, myocardial oxygen consumption, and coronary sinus oxygen content under basal conditions were determined. RESULTS: In the aorta, mean (SD) concentrations of ET-1 (IDCM 0.76 (0.25) v controls 0.31 (0.06) fmol/ml; p = 0.002) and BET (IDCM 3.58 (1.06) v controls 2.11 (0.58) fmol/ml; p = 0.014) were increased in patients with IDCM. Aortic ET-1 concentrations correlated positively with NYHA class (r = 0. 731; p < 0.001), myocardial oxygen consumption (r = 0.749; p < 0. 001), and coronary blood flow (r = 0.645; p = 0.003), but inversely with coronary sinus oxygen content (r = -0.633; p = 0.004), which was significantly decreased in IDCM patients (IDCM 4.68 (1.05) v controls 6.70 (1.06) vol%; p = 0.003). CONCLUSIONS: The coronary circulation in patients with IDCM is exposed to an increased endothelin load. ET-1 concentrations correlate with functional deterioration. A decrease of the coronary sinus content of oxygen suggests a mismatch between coronary blood flow and metabolic demand. Thus, ET-1 might be a marker of a disequilibrium between myocardial oxygen demand and coronary blood flow in IDCM.