Yukiji Takeda

In vivo cardiovasculogenesis by direct injection of isolated adult mesenchymal stem cells.

The characterization of mesenchymal stem cells (MSCs) is of biological and clinical interest. We demonstrate that isolated MSCs, defined by CD34(low) c-kit(+) CD140a(+) Sca-1(high), are able to differentiate into cardiomyocytes, endothelial cells, and pericytes or smooth muscle cells by direct injection into adult heart. In skeletal muscle and lung, they also contributed to formation of the vasculature. MSCs did not transform into malignant cells or form excess extracellular matrix. This study suggests that MSCs may supply an ideal donor source of cardiovascular cells in patients with cardiopulmonary diseases.

Thin-cap fibroatheroma and microchannel findings in optical coherence tomography correlate with subsequent progression of coronary atheromatous plaques.

AIMS Morphological characteristics of non-significant coronary plaques (NSCPs) that develop rapid progression have not been fully elucidated. The aim of this study was to clarify the morphological characteristics of NSCPs in patients with coronary artery disease (CAD) using intravascular optical coherence tomography (OCT). METHODS AND RESULTS Fifty-three consecutive CAD patients undergoing percutaneous coronary intervention were enrolled and 69 NSCPs (per cent diameter stenosis <50%) were identified on baseline angiogram. Baseline characteristics of NSCPs were evaluated by OCT, and patients were followed-up prospectively. At the second coronary angiography, the baseline OCT characteristics and plaque progression were correlated. During the 7-month follow-up period, 13 NSCPs showed angiographic progression and 56 NSCPs did not. Baseline minimum lumen diameter and diametric stenosis were similar between NSCPs with and without progression. Compared with NSCPs without progression, those with progression showed a significantly higher incidence of intimal laceration (61.5 vs. 8.9%, P < 0.01), microchannel (76.9 vs. 14.3%, P < 0.01), lipid pools (100 vs. 60.7%, P = 0.02), thin-cap fibroatheroma (TCFA) (76.9 vs. 14.3%, P < 0.01), macrophage images (61.5 vs. 14.3%, P < 0.01), and intraluminal thrombi (30.8 vs. 1.8%, P < 0.01). Univariate regression analysis showed that TCFA and microchannel images showed high correlation with subsequent luminal progression [odds ratio (OR): 20.0, P < 0.01 and OR: 20.0, P < 0.01, respectively]. CONCLUSION Optical coherence tomography-based complex characteristics of TCFA and microchannel were the potential predictors of subsequent progression of NSCPs in patients with CAD.

Combination of hTERT and bmi-1, E6, or E7 Induces Prolongation of the Life Span of Bone Marrow Stromal Cells from an Elderly Donor without Affecting Their Neurogenic Potential

ABSTRACT Murine bone marrow stromal cells differentiate not only into mesodermal derivatives, such as osteocytes, chondrocytes, adipocytes, skeletal myocytes, and cardiomyocytes, but also into neuroectodermal cells in vitro. Human bone marrow stromal cells are easy to isolate but difficult to study because of their limited life span. To overcome this problem, we attempted to prolong the life span of bone marrow stromal cells and investigated whether bone marrow stromal cells modified with bmi-1, hTERT, E6, and E7 retained their differentiated capability, or multipotency. In this study, we demonstrated that the life span of bone marrow stromal cells derived from a 91-year-old donor could be extended and that the stromal cells with an extended life span differentiated into neuronal cells in vitro. We examined the neuronally differentiated cells morphologically, physiologically, and biologically and compared the gene profiles of undifferentiated and differentiated cells. The neuronally differentiated cells exhibited characteristics similar to those of midbrain neuronal progenitors. Thus, the results of this study support the possible use of autologous-cell graft systems to treat central nervous system diseases in geriatric patients.

Long-term follow-up of neointimal coverage of sirolimus-eluting stents--evaluation with optical coherence tomography.

BACKGROUND Late stent thrombosis related to delayed neointimal growth is a major concern after drug-eluting stent (DES) implantation. The time course of neointimal growth and risk factors of uncovered stent struts after sirolimus-eluting stent (SES) was studied using optical coherence tomography (OCT). METHODS AND RESULTS The 60 patients were enrolled and classified into G1 (follow-up period <9 months, n=27), G2 (9-24 months, n=18), and G3 (>25 months, n=15). The time elapsed since SES implantation was associated with a significant increase in mean neointimal area and neointimal thickness, and also with a significant decrease in the number of uncovered stent struts (G1: 14.8%, G2: 11.7%, and G3: 4.1%, P<0.001). However, only 17.6% of implanted SES was completely covered by neointima, even in the G3 period. Small-diameter SES, complex coronary lesions with lipid and calcium content adjacent to stent struts, and diabetes predicted delayed neointimal coverage of SES struts in G1. CONCLUSIONS Neointima inside SES progressively increases after the routine follow-up period, but only a few SES were completely covered at 3 years after implantation. OCT is a useful modality for assessing neointimal formation after SES implantation, and may give important information about the strategy of antiplatelet therapy after DES implantation.

Usefulness of soluble Fms-like tyrosine kinase-1 as a biomarker of acute severe heart failure in patients with acute myocardial infarction.

Placental growth factor and vascular endothelial growth factor increase angiogenesis and promote healing after acute myocardial infarction (MI), but the significance of soluble Fms-like tyrosine kinase-1 (sFlt-1), an antagonist of placental growth factor and vascular endothelial growth factor, in the setting of acute MI has not been elucidated. The development of acute heart failure in the immediate period after MI is a dreaded complication, but there are no useful biomarkers that identify patients at risk of acute heart failure. We wished to investigate the clinical significance of circulating sFlt-1 during acute MI. We enrolled 174 patients with acute MI, and arterial blood sampling was performed. Plasma levels of sFlt-1 were measured by enzyme-linked immunosorbent assay and their relation to clinical parameters was analyzed. Circulating levels of sFlt-1 on admission were significantly increased in patients with acute MI compared to controls (528.1 +/- 290.9 vs 355.7 +/- 205.0 pg/ml, p <0.001). Circulating levels of sFlt-1 on admission were significantly higher in patients who developed severe acute heart failure requiring mechanical circulatory support devices compared to those with stable hemodynamics (611.4 +/- 373.6 vs 494.6 +/- 243.9 pg/ml, p = 0.016). Moreover, circulating levels of sFlt-1 on admission were directly related to duration of hospitalization. Multivariate logistic analysis showed that hemodynamic instability was predicted by sFlt-1 on admission and left ventricular systolic pressure. In conclusion, the circulating level of sFlt-1 is increased in patients with acute MI, and the sFlt-1 level on admission is a promising biomarker for the development of severe acute heart failure after MI.

Reduction of Circulating Soluble Fms-Like Tyrosine Kinase-1 Plays a Significant Role in Renal Dysfunction–Associated Aggravation of Atherosclerosis

Background— Renal dysfunction is commonly accompanied by a worsening of atherosclerosis; however, the underlying molecular mechanism is not fully understood. We examined the role played by soluble fms-like tyrosine kinase-1 (sFlt-1), an endogenous antagonist of the proatherogenic cytokine placental growth factor (PlGF), in the worsening of atherosclerosis in patients with renal dysfunction and in an animal model of renal failure. Methods and Results— In this study, 329 patients who received cardiac catheterization and 76 patients who underwent renal biopsy were enrolled. Both plasma sFlt-1 levels and renal sFlt-1 mRNA expression were positively correlated with estimated glomerular filtration rate (P<0.01). The PlGF/sFlt-1 ratio was negatively correlated with estimated glomerular filtration rate (P<0.01), whereas plasma PlGF levels were not affected by it. The PlGF/sFlt-1 ratio was significantly higher in patients with multivessel coronary artery disease than in patients with single-vessel or no coronary artery disease. The reduction of circulating sFlt-1 and renal sFlt-1 mRNA levels was confirmed in five-sixths (5/6)–nephrectomized apolipoprotein E–deficient mice that developed experimental renal dysfunction. Atherosclerotic plaque area and macrophage infiltration into the plaque were significantly higher in 5/6–nephrectomized apolipoprotein E–deficient mice than in control mice, but replacement therapy with recombinant sFlt-1 significantly reduced both plaque formation and macrophage infiltration. Conclusions— The present study demonstrates that a reduction in the circulating levels of sFlt-1 is associated with the worsening of atherosclerosis that accompanies renal dysfunction.

Morphological features of coronary arteries in patients with coronary spastic angina: Assessment with intracoronary optical coherence tomography

BACKGROUND Coronary spasm (CS) plays an important role in the pathogenesis of many types of ischemic heart disease, but morphological appearance of non-stenotic coronary segments with CS is not fully understood. We evaluate the morphological characteristics of coronary arteries in patients with coronary spastic angina (CSA) using intravascular optical coherence tomography (OCT). METHODS We evaluated 37 patients with resting chest pain whose coronary angiograms did not reveal significant stenosis. These patients underwent an acetylcholine (ACh) provocation test. OCT was performed after complete dilatation of coronary arteries, and additionally during ACh-induced CS in four patients. RESULTS Based on the ACh test, 23 patients were diagnosed as having CSA, and the remaining 14 patients without CS were referred to as CS-negative. OCT study revealed that coronary segments with ACh-induced CS had homogeneous intimal thickening, and quantitative analysis showed that CS-positive segments had a significantly greater intima area as compared with corresponding CS-negative segments without lipid or calcium content. By contrast, CS-positive segments had a significantly smaller intima area as compared with CS-negative segments with lipid or calcium deposit. During ACh-induced CS, lumen and total vascular areas were significantly decreased, whereas intima area did not change in comparison with complete vasodilatation. The luminal surface of the intima formed a markedly wavy configuration during CS. CONCLUSIONS Coronary artery segments involved in CS are characterized by diffuse intimal thickening without lipid or calcium content. High-resolution coronary OCT imaging could make it possible to analyze the vascular pathophysiology in patients with CS.

Diagnostic accuracy of dual-source computed tomography in the characterization of coronary atherosclerotic plaques: Comparison with intravascular optical coherence tomography

BACKGROUND Dual-source computed tomography (DSCT) has enabled us to non-invasively visualize coronary artery stenosis, but its ability to characterize coronary atherosclerotic plaques (ASPs) has not been evaluated. Intravascular optical coherence tomography (OCT) provides tissue images of coronary artery wall that are validated by pathohistological studies. We studied the diagnostic accuracy of DSCT in the characterization of coronary ASPs, especially lipid-rich ASP with thin fibrous cap (TCFA), in comparison with OCT. METHODS DSCT and OCT were used to image non-stenotic ASPs in non-culprit coronary arteries of 17 acute coronary syndrome (ACS) patients, and 162 coronary regions were enrolled. RESULTS The mean CT values of fibrous ASP, ASP with lipid core, and ASP with calcium deposit were 77.5, 28.9, and 515.9 HU, respectively (P<0.0001). ASP with calcium deposit was detected with a sensitivity of 88.9% and a specificity of 98.6%, while ASP with lipid core was detected by DSCT with a relatively low sensitivity of 73.1% and a high specificity of 94.0%. In TCFA, cross-sectional areas of both ASP and lipid core were significantly larger, mean CT value of ASP was significantly lower, and concomitant calcification was more frequently observed compared with lipid-rich ASP with thick fibrous cap (ThCFA). The combination of these CT parameters seems to be a useful index for the differentiation of TCFA from ThCFA. CONCLUSION DSCT is useful for non-invasive evaluation of calcified and fibro-fatty tissue characters in coronary artery plaque, but it is still not able to differentiate TCFA, one of the features of vulnerable plaque.

Inflammatory Response to Acute Myocardial Infarction Augments Neointimal Hyperplasia After Vascular Injury in a Remote Artery

Objective—Percutaneous coronary intervention (PCI) is currently the most widely accepted treatment for acute myocardial infarction (AMI). It remains unclear, however, whether post-AMI conditions might exacerbate neointimal hyperplasia and restenosis following PCI. Given that both a medial smooth muscle cell lineage and a bone marrow (BM)-derived hematopoietic stem cell lineage are now thought to contribute to neointima formation, the primary aims of the present study were to determine whether AMI augments neointimal hyperplasia at sites of arterial injury, and whether BM-derived cells contribute to that process. Methods and Results—We simultaneously generated models of AMI and arterial injury in the same mice, some of which had received BM transplantation. We found that AMI augments neointimal hyperplasia at sites of femoral artery injury by ≈35% (P<0.05), but that while BM-derived cells contributed to neointimal hyperplasia, they did not contribute to the AMI-related augmentation. Expression of interleukin (IL)-6 mRNA was ≈7-fold higher in the neointimas of mice subjected to both AMI and arterial injury than in those of mice subjected to arterial injury alone. In addition, we observed increased synthesis of tumor necrosis factor (TNF)-&agr; within infarcted hearts and TNF-&agr; receptor type 1 (TNFR1) within injured arteries. Chronic treatment with pentoxifylline, which mainly inhibits TNF-&agr; synthesis, reduced levels of circulating TNF-&agr; and attenuated neointimal hyperplasia after AMI. Conclusions—Conditions after AMI could exacerbate postangioplasty restenosis, not by increasing mobilization of BM-derived cells, but by stimulating signaling via TNF-&agr;, TNFR1 and IL-6.

Acute myocardial infarction as a systemic prothrombotic condition evidenced by increased von Willebrand factor protein over ADAMTS13 activity in coronary and systemic circulation

The aim of the present study is to clarify the roles of circulating ADAMTS13 and von Willebrand factor (VWF) in the formation of coronary artery thrombi in acute myocardial infarction (AMI). Twenty-six AMI patients, 37 age-matched healthy controls, and 20 young controls were studied. Plasma ADAMTS13 activity and levels of VWF antigen (VWF: Ag) and unusually large VWF multimer (UL-VWFM) were measured in the femoral vein (FV), aortic root (Ao), and coronary sinus (Cs) immediately before percutaneous coronary intervention (PCI) during the acute phase of AMI, as well as 6 months later. During the acute phase of AMI, plasma levels of VWF: Ag were similar in FV, Ao, and Cs, and were higher than those of age-matched control. In contrast, ADAMTS13 activity in three sampling points in AMI patients was similar to that of age-matched controls. Thus, the ratio of VWF: Ag to ADAMTS13 activity in the acute phase of AMI was significantly higher in all three sampled sites than that of age-matched controls. In the chronic phase, plasma levels of VWF: Ag, ADAMTS13 activity, and the ratio of VWF: Ag to ADAMTS13 activity were similar to those of age-matched controls. UL-VWFM was detected in the acute phase of AMI but not in the chronic phase. The present study showed that the plasma VWF: Ag levels are increased and ADAMTS13 activity is relatively decreased in both systemic and coronary circulation during the acute phase of AMI, suggesting that an imbalance between the enzyme and its substrate may play a role in the formation of occlusive thrombi in a coronary artery.