摘要
BACKGROUND Mesenchymal stem cells(MSC)modified by gene transfer to express cardiac pacemaker channels such as HCN2 or HCN4 were shown to elicit pacemaker function after intracardiac transplantation in experimental animal models.Human MSC derived from adipose tissue(haMSC)differentiate into cells with pacemaker properties in vitro,but little is known about their behavior after intracardiac transplantation.AIM To investigate whether haMSC elicit biological pacemaker function in vivo after transplantation into pig hearts.METHODS haMSC under native conditions(nhaMSC)or after pre-conditioning by medium differentiation(dhaMSC)(n=6 pigs each,5×106 cells/animal)were injected into the porcine left ventricular free wall.Animals receiving PBS injection served as controls(n=6).Four weeks later,total atrioventricular(AV)-block was induced by radiofrequency catheter ablation,and electronic pacemaker devices were implanted for backup stimulation and heart rate monitoring.Ventricular rate and rhythm of pigs were evaluated during a follow-up of 15 d post ablation by 12-lead-ECG with heart rate assessment,24-h continuous rate monitoring recorded by electronic pacemaker,assessment of escape recovery time,and pharmacological challenge to address catecholaminergic rate response.Finally,hearts were analyzed by histological and immunohistochemical investigations.RESULTS In vivo transplantation of dhaMSC into the left ventricular free wall of pigs elicited spontaneous and regular rhythms that were pace-mapped to ventricular injection sites(mean heart rate 72.2±3.6 bpm;n=6)after experimental total AV block.Ventricular rhythms were stably detected over a 15-d period and were sensitive to catecholaminergic stimulation(mean maximum heart rate 131.0±6.2 bpm;n=6;P<0.001).Pigs,which received nhaMSC or PBS presented significantly lower ventricular rates(mean heart rates 47.2±2.5 bpm and 37.4±3.2 bpm,respectively;n=6 each;P<0.001)and exhibited little sensitivity towards catecholaminergic stimulation(mean maximum heart rates 76.4±3.1 bpm an
基金
Max-Planck-Society(TANDEM project to Koenen M and Schweizer PA)
Ministry of Science,Research and the Arts Baden-Wuerttemberg(Sonderlinie Medizin to Thomas D)
German Heart Foundation(Kaltenbach scholarship to Darche FF)
German Cardiac Society(Otto-Hess scholarship to Rahm AK)
Heidelberg Medical Faculty(Physician Scientist-Programm to Darche FF,Rivinius R and Rahm AK)
German Cardiac Society(Research scholarship to Rivinius R)
the German Society of Internal Medicine(Clinician-Scientist-Program to Rahm AK)
and the German Centre for Cardiovascular Research(DZHK).
