Visibility of Pulmonary Valve and Pulmonary Regurgitation on Intracardiac Echocardiography in Adult Patients with Tetralogy of Fallot

Pulmonary regurgitation (PR) is a risk factor for sudden cardiac death in adult patients with repaired tetralogy of Fallot (TOF). However, transthoracic echocardiography (TTE) cannot fully visualize the pulmonary valve (PV) and PR. We investigated whether intracardiac echocardiography (ICE) could visualize the PV and PR better than TTE. Thirty adult patients with TOF (mean age 33 ± 15 years) scheduled for cardiac catheterization underwent ICE. The visualization of PV and the severity of PR were classified into three grades. ICE depicted the PV better than TTE (ICE vs. TTE: not visualized, partially visualized, and fully visualized: n = 1 [3%], n = 13 [43%], and n = 16 [53%] vs. n = 14 [47%], n = 13 [43%], and n = 3 [10%], p p = 0.004), while there was no discrepancy between the results of ICE and MRI (21 [72%] vs. 22 [76%], p = 1.000). In comparison to TTE, ICE can safely provide better visualization of the PV and PR in adults with TOF, especially in patients who have undergone PVR

Hepatocyte growth factor mobilizes non-bone marrow-derived circulating mesoangioblasts

AIMS: The identification of factors that mobilize subsets of endogenous progenitor cells may provide new therapeutic tools to enhance the repair of ischaemic tissue. We previously identified circulating mesenchymal cells that co-express endothelial markers (so-called circulating mesoangioblasts, cMABs) in children undergoing heart surgery with cardiopulmonary bypass (CPB). However, the mechanisms by which these cells are mobilized and their origin is unclear. METHODS AND RESULTS: Circulating CD73(+)CD45(-)KDR(+) cMABs were analysed in adults undergoing heart surgery with (n = 21) or without CPB (n = 8). During surgery with CPB, cMABs are mobilized with a maximal response at the end of the operation. In contrast, off-pump heart surgery does not stimulate cMAB mobilization, indicating that the stress mediated by CPB induces the mobilization of cMAB. Circulating mesoangioblasts were enriched in blood obtained from the coronary sinus. Histologically, CD73(+) cells were detected around vessels in the heart, indicating that the heart is one of the niches of cMABs. Consistently, studies in gender mismatched bone marrow transplanted patients demonstrated that cMABs did not originate from the bone marrow. Cytokine profiling of serum samples revealed that hepatocyte growth factor (HGF) was profoundly increased at the time point of maximal mobilization of cMABs. Hepatocyte growth factor stimulated the migration of cMABs. Importantly, injection of recombinant HGF increased cMABs in rats. CONCLUSIONS: Hepatocyte growth factor induces mobilization of non-haematopoietic progenitor cells with a cardiac repair capacity. This newly identified function together with the known pleiotrophic effects of HGF makes HGF an attractive therapeutic option for the treatment of ischaemic heart disease

Sox2 Transduction enhances cardiovascular repair capacity of blood-derived mesoangioblasts

Rationale: Complementation of pluripotency genes may improve adult stem cell functions. Objectives: Here we show that clonally expandable, telomerase expressing progenitor cells can be isolated from peripheral blood of children. The surface marker profile of the clonally expanded cells is distinct from hematopoietic or mesenchymal stromal cells, and resembles that of embryonic multipotent mesoangioblasts. Cell numbers and proliferative capacity correlated with donor age. Isolated circulating mesoangioblasts (cMABs) express the pluripotency markers Klf4, c-Myc, as well as low levels of Oct3/4, but lack Sox2. Therefore, we tested whether overexpression of Sox2 enhances pluripotency and facilitates differentiation of cMABs in cardiovascular lineages. Methods and Results: Lentiviral transduction of Sox2 (Sox-MABs) enhanced the capacity of cMABs to differentiate into endothelial cells and cardiomyocytes in vitro. Furthermore, the number of smooth muscle actin positive cells was higher in Sox-MABs. In addition, pluripotency of Sox-MABs was shown by demonstrating the generation of endodermal and ectodermal progenies. To test whether Sox-MABs may exhibit improved therapeutic potential, we injected Sox-MABs into nude mice after acute myocardial infarction. Four weeks after cell therapy with Sox-MABs, cardiac function was significantly improved compared to mice treated with control cMABs. Furthermore, cell therapy with Sox-MABs resulted in increased number of differentiated cardiomyocytes, endothelial cells, and smooth muscle cells in vivo. Conclusions: The complementation of Sox2 in Oct3/4-, Klf4-,and c-Myc-expressing cMABs enhanced the differentiation into all 3 cardiovascular lineages and improved the functional recovery after acute myocardial infarction. (Circ Res. 2010;106:1290-1302.)Stem cells & developmental biolog