Abstract-Bone marrow mononuclear cells (BMCs) from 20 patients with extensive reperfused myocardial infarction (MI) were used to assess their myocardial regenerative capability "in vitro" and their effect on postinfarction left ventricular (LV) remodeling. Human BMCs were labeled, seeded on top of cryoinjured mice heart slices, and cultured. BMCs showed tropism for and ability to graft into the damaged mouse cardiac tissue and, after 1 week, acquired a cardiomyocyte phenotype and expressed cardiac proteins, including connexin43. In the clinical trial, autologous BMCs (78Ϯ41ϫ10 6 per patient) were intracoronarily transplanted 13.5Ϯ5.5 days after MI. There were no adverse effects on microvascular function or myocardial injury. No major cardiac events occurred up to 11Ϯ5 months. At 6 months, magnetic resonance showed a decrease in the end-systolic volume, improvement of regional and global LV function, and increased thickness of the infarcted wall, whereas coronary restenosis was only 15%. No changes were found in a nonrandomized contemporary control group. Thus, BMCs are capable of nesting into the damaged myocardium and acquire a cardiac cell phenotype in vitro as well as safely benefiting ventricular remodeling in vivo. Large-scale randomized trials are needed now to assess the clinical efficacy of this treatment.

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The aim of this study was to determine the existence of the circadian rhythm (CR) in the onset of acute myocardial infarction (AMI) in different patient subgroups. Information was collected about 41,244 infarctions from the database of the ARIAM (Analysis of Delay in AMI) Spanish multicenter study. CR in AMI were explored in subgroups of cases categorized by age, gender, previous ischemic heart disease (PIHD), outcome in coronary care unit, infarction electrocardiograph (ECG) characteristics (Q wave or non-Q wave), and location of AMI. Cases were classified according to these variables in the different subgroups. To verify the presence of CR, a simple test of equality of time series based on the multiple-sinusoid (24, 12, and 8 h periods) cosinor analysis was developed. For the groups as a whole, the time of pain onset as an indicator of the AMI occurrence showed a CR (p<0.0001), with a morning peak at 10:10 h. All the analyzed subgroups also showed CR. Comparison between subgroups showed significant differences in the PIHD (p<0.01) and infarction ECG characteristics (p<0.01) groups. The CR of the subgroup with Q-wave infarction differed from that of non-Q wave subgroup (p<0.01) when the patients had PIHD (23% in Q wave infarction vs. 39.2% in non-Q wave). AMI onset followed a CR pattern, which is also observed in all analyzed subgroups. Differences in the CR according to the Q/non-Q wave infarction characteristics could be determined by PIHD. The cosinor model fit with three components (24, 12, and 8 h periods) showed a higher sensitivity than the single 24 h period analysis.

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