Hyung n Joo

Stromal Vascular Fraction From Adipose Tissue Forms Profound Vascular Network Through the Dynamic Reassembly of Blood Endothelial Cells

Objective—Tremendous efforts have been made to establish effective therapeutic neovascularization using adipose tissue-derived stromal vascular fraction (SVF), but the efficiency is low, and underlying mechanisms and their interaction with the host in a new microenvironment are poorly understood. Methods and Results—Here we demonstrate that direct implantation of SVF derived from donor adipose tissue can create a profound vascular network through the disassembly and reassembly of blood endothelial cells at the site of implantation. This neovasculature successfully established connection with recipient blood vessels to form a functionally perfused circuit. Addition of vascular growth factors to the SVF implant improved the efficiency of functional neovasculature formation. In contrast, spheroid culture of SVF before implantation reduced the capacity of vasculature formation, possibly because of cellular alteration. Implanting SVF into the mouse ischemic hindlimb induced the robust formation of a local neovascular network and salvaged the limb. Moreover, the coimplantation of SVF prevented fat absorption in the subcutaneous adipose tissue graft model. Conclusion—Freshly isolated SVF can effectively induce new vessel formation through the dynamic reassembly of blood endothelial cells and could be applied to achieve therapeutic neovascularization for relieving ischemia and preventing fat absorption in an autologous manner.

Angiopoietin-1 promotes endothelial differentiation from embryonic stem cells and induced pluripotent stem cells.

Angiopoietin-1 (Ang1) plays a crucial role in vascular and hematopoietic development, mainly through its cognate receptor Tie2. However, little is known about the precise role of Ang1 in embryonic stem cell (ESC) differentiation. In the present study, we used COMP-Ang1 (a soluble and potent variant of Ang1) to explore the effect of Ang1 on endothelial and hematopoietic differentiation of mouse ESCs in an OP9 coculture system and found that Ang1 promoted endothelial cell (EC) differentiation from Flk-1(+) mesodermal precursors. This effect mainly occurred through Tie2 signaling and was altered in the presence of soluble Tie2-Fc. We accounted for this Ang1-induced expansion of ECs as enhanced proliferation and survival. Ang1 also had an effect on CD41(+) cells, transient precursors that can differentiate into both endothelial and hematopoietic lineages. Intriguingly, Ang1 induced the preferential differentiation of CD41(+) cells toward ECs instead of hematopoietic cells. This EC expansion promoted by Ang1 was also recapitulated in induced pluripotent stem cells (iPSCs) and human ESCs. We successfully achieved in vivo neovascularization in mice by transplantation of ECs obtained from Ang1-stimulated ESCs. We conclude that Ang1/Tie2 signaling has a pivotal role in ESC-EC differentiation and that this effect can be exploited to expand EC populations.

ABCG2 polymorphisms, 34G>A and 421C>A in a Korean population: analysis and a comprehensive comparison with other populations.

Background and objective:  ABCG2, also known as Breast Cancer Resistance Peptide (BCRP) or mitoxantrone‐resistant protein, is the second member of the G‐family of ABC transporters. The frequencies of ABCG2 34G>A and 421C>A polymorphisms in a Korean population were assessed using a newly developed multiplex pyrosequencing method, and compared with the corresponding frequencies seen in other ethnic groups.

Effects of Black Raspberry on Lipid Profiles and Vascular Endothelial Function in Patients with Metabolic Syndrome

Black raspberry (Rubus occidentalis) has been known for its anti‐inflammatory and anti‐oxidant effects. However, short‐term effects of black raspberry on lipid profiles and vascular endothelial function have not been investigated in patients with metabolic syndrome. Patients with metabolic syndrome (n = 77) were prospectively randomized into a group with black raspberry (n = 39, 750 mg/day) and a placebo group (n = 38) during a 12‐week follow‐up. Lipid profiles, brachial artery flow‐mediated dilatation (baFMD), and inflammatory cytokines such as IL‐6, TNF‐α, C‐reactive protein, adiponectin, sICAM‐1, and sVCAM‐1 were measured at the baseline and at the 12‐week follow‐up. Decreases from the baseline in the total cholesterol level (−22.8 ± 30.4 mg/dL vs. −1.9 ± 31.8 mg/dL, p < 0.05, respectively) and total cholesterol/HDL ratio (−0.31 ± 0.64 vs. 0.07 ± 0.58, p < 0.05, respectively) were significantly greater in the group with black raspberry than in the placebo group. Increases in baFMD at the 12‐week follow‐up were significantly greater in the group with black raspberry than in the placebo group (0.33 ± 0.44 mm vs. 0.10 ± 0.35 mm, p < 0.05, respectively). Decreases from the baseline in IL‐6 (−0.4 ± 1.5 pg/mL vs. −0.1 ± 1.0 pg/mL, p < 0.05, respectively) and TNF‐α (−2.9 ± 4.7 pg/mL vs. 0.1 ± 3.6 pg/mL, p < 0.05, respectively) were significantly greater in the group with black raspberry. The use of black raspberry significantly decreased serum total cholesterol level and inflammatory cytokines, thereby improving vascular endothelial function in patients with metabolic syndrome during the 12‐week follow‐up. Copyright

Human endothelial colony forming cells from adult peripheral blood have enhanced sprouting angiogenic potential through up-regulating VEGFR2 signaling

BACKGROUND Endothelial colony forming cells (ECFCs), a subtype of endothelial progenitor cells, have been studied as a promising cellular source for therapeutic angiogenesis. Although ECFCs are very similar to mature endothelial cells, details regarding the role of ECFCs during angiogenesis are not known. We compared the cellular and angiogenic properties of ECFCs and mature endothelial cells (HUVECs). METHODS HUVECs were used as control. Quantitative RT-PCR, western blotting, immunofluorescence staining, flow cytometric analyses and angiogenic cytokine array were performed. 3D-microfluidic angiogenesis assay system was adopted for in vitro angiogenic potential. In vivo angiogenic potential was assessed by Matrigel plug assay. RESULTS ECFCs had higher expression of activated endothelial tip cell markers (Dll4, CXCR4, CD34, and VCAM1) and arterial genes (DLL4 and CX40), but lower expression of venous and lymphatic genes (COUP-TFII and PROX1). In 3D-microfluidic angiogenesis assay system, ECFCs induced robust sprouting vascular structures. Co-cultivation of both ECFCs and HUVECs gave rise to lumen-formed hybrid vascular structures, with the resulting ECFCs predominantly localized to the tip portion. This finding suggests that the ECFC has a role as a sprouting endothelial tip cell. Interestingly, VEGF-A phosphorylated VEGFR2 and its downstream signaling molecules more strongly in ECFCs than in HUVECs. Even small amount of VEGF-A successfully induced the sprouting angiogenesis of ECFCs. Finally, co-administration of ECFCs and human dermal fibroblasts successfully induced lumen-formed maturated neovessels in vivo. CONCLUSION ECFCs derived from adult peripheral blood had enhanced sprouting angiogenic potential in vitro and in vivo through up-regulation of the VEGFR2 signaling pathway.

Visceral Fat Area and Serum Adiponectin Level Predict the Development of Metabolic Syndrome in a Community-Based Asymptomatic Population.

Background Although it has been demonstrated that visceral adipose tissue content and serum levels of adiponectin are associated with metabolic syndrome, their predictive potential for the development of metabolic syndrome remains to be elucidated. Methods We studied 1,130 participants of the Seoul Metabolic Syndrome cohort. A total of 337 subjects without metabolic syndrome underwent the follow-up evaluation and finally analyzed. Visceral fat area (VFA) was measured using dual bioelectrical impedance analysis. We compared the 1-year incidence rate of metabolic syndrome among four different groups: Group 1 (high adiponectin level and low VFA), Group 2 (low adiponectin level and low VFA), Group 3 (high adiponectin level and high VFA) and Group 4 (low adiponectin level and high VFA). Results Median follow-up duration was 17 months. Cut-off points of adiponectin level and VFA for metabolic syndrome were 7.34 ng/ml and 84 cm2 for men, and 12.55 and 58 cm2 ng/ml for women, respectively. The incidence of metabolic syndrome was the highest in Group 4 (Group 1; 16.47%, Group 2; 22.08%, Group 3; 25%, and Group 4; 46.15%, p<0.001). Adjusted logistic regression analyses for metabolic syndrome prediction demonstrated that Group 4 exhibited the highest odds ratio compared with Group 1 (4.918 [2.05–11.795]), which was predominantly affected by waist circumference and serum triglyceride levels. Notably, triglyceride/high-density lipoprotein cholesterol (TG/HDL) ratio was significantly higher in Group 4 (p = 0.017). Conclusion Incidence rate of metabolic syndrome was the highest in subjects with low serum adiponectin levels and high visceral fat area. Higher TG/HDL ratio in these subjects suggested insulin resistance may contribute to the development of metabolic syndrome.

Triple antithrombotic therapy versus dual antiplatelet therapy in patients with atrial fibrillation undergoing drug-eluting stent implantation

BackgroundThe optimal antithrombotic regimen in patients with atrial fibrillation (AF) undergoing drug-eluting stent (DES) implantation for complex coronary artery disease is unclear. We compared the net clinical outcomes of triple antithrombotic therapy (TAT; aspirin, thienopyridine, and warfarin) and dual antiplatelet therapy (DAPT; aspirin and thienopyridine) in AF patients who had undergone DES implantation. MethodsA total of 367 patients were enrolled and analyzed retrospectively; 131 patients (35.7%) received TAT and 236 patients (64.3%) received DAPT. DAPT and warfarin were maintained for a minimum of 12 and 24 months, respectively. The primary endpoint was the 2-year net clinical outcomes, a composite of major bleeding and major adverse cardiac and cerebral events (MACCE). Propensity score-matching analysis was carried out in 99 patient pairs. ResultsThe 2-year net clinical outcomes of the TAT group were worse than those of the DAPT group (34.3 vs. 21.1%, P=0.006), which was mainly due to the higher incidence of major bleeding (16.7 vs. 4.6%, P<0.001), without any significant increase in MACCE (22.1 vs. 17.7%, P=0.313). In the multivariate analysis, TAT was an independent predictor of worse net clinical outcomes (odds ratio 1.63, 95% confidence interval 1.06–2.50) and major bleeding (odds ratio 3.54, 95% confidence interval 1.65–7.58). After propensity score matching, the TAT group still had worse net clinical outcomes and a higher incidence of major bleeding compared with the DAPT group. ConclusionIn AF patients undergoing DES implantation, prolonged administration of TAT may be harmful due to the substantial increase in the risk for major bleeding without any reduction in MACCE.

Transplantation of Immortalized CD34+ and CD34- Adipose-Derived Stem Cells Improve Cardiac Function and Mitigate Systemic Pro-Inflammatory Responses

Adipose-derived stem cells (ADSCs) have the potential to differentiate into various cell lineages and they are easily obtainable from patients, which makes them a promising candidate for cell therapy. However, a drawback is their limited life span during in vitro culture. Therefore, hTERT-immortalized CD34+ and CD34- mouse ADSC lines (mADSCshTERT) tagged with GFP were established. We evaluated the proliferation capacity, multi-differentiation potential, and secretory profiles of CD34+ and CD34- mADSCshTERT in vitro, as well as their effects on cardiac function and systemic inflammation following transplantation into a rat model of acute myocardial infarction (AMI) to assess whether these cells could be used as a novel cell source for regeneration therapy in the cardiovascular field. CD34+ and CD34- mADSCshTERT demonstrated phenotypic characteristics and multi-differentiation potentials similar to those of primary mADSCs. CD34+ mADSCshTERT exhibited a higher proliferation ability compared to CD34- mADSCshTERT, whereas CD34- mADSCshTERT showed a higher osteogenic differentiation potential compared to CD34+ mADSCshTERT. Primary mADSCs, CD34+, and CD34- mADSCshTERT primarily secreted EGF, TGF-β1, IGF-1, IGF-2, MCP-1, and HGFR. CD34+ mADSCshTERT had higher secretion of VEGF and SDF-1 compared to CD34- mADSCshTERT. IL-6 secretion was severely reduced in both CD34+ and CD34- mADSCshTERT compared to primary mADSCs. Transplantation of CD34+ and CD34- mADSCshTERT significantly improved the left ventricular ejection fraction and reduced infarct size compared to AMI-induced rats after 28 days. At 28 days after transplantation, engraftment of CD34+ and CD34- mADSCshTERT was confirmed by positive Y chromosome staining, and differentiation of CD34+ and CD34- mADSCshTERT into endothelial cells was found in the infarcted myocardium. Significant decreases were observed in circulating IL-6 levels in CD34+ and CD34- mADSCshTERT groups compared to the AMI-induced control group. Transplantation of CD34- mADSCshTERT significantly reduced circulating MCP-1 levels compared to the AMI control and CD34+ mADSCshTERT groups. GFP-tagged CD34+ and CD34- mADSCshTERT are valuable resources for cell differentiation studies in vitro as well as for regeneration therapy in vivo.

INNOVATION Study (Impact of Immediate Stent Implantation Versus Deferred Stent Implantation on Infarct Size and Microvascular Perfusion in Patients With ST-Segment–Elevation Myocardial Infarction)

Background—The aim of this study was to assess whether deferred stenting (DS) reduces infarct size and microvascular obstruction (MVO) compared with immediate stenting (IS) in primary percutaneous coronary intervention for ST-segment–elevation myocardial infarction. Methods and Results—From February 2013 to August 2015, 114 patients (mean age: 69 years) were randomized into the following 2 groups: DS with an intention to stent 3 to 7 days later or IS after primary reperfusion in 2 centers. The primary and secondary end points were infarct size and the incidence of MVO, respectively, assessed by cardiac magnetic resonance imaging at 30 days after primary reperfusion. The median time to the second procedure in the DS was 72.8 hours. Six patients in the DS group were crossed over to the IS group because of progression of dissection or safety concerns after randomization. In the intention-to-treat analysis, DS did not significantly reduce infarct size (15.0% versus 19.4%; P=0.112) and the incidence of MVO (42.6% versus 57.4%; P=0.196), compared with IS. However, in anterior wall myocardial infarction, infarct size (16.1% versus 22.7%; P=0.017) and the incidence of MVO (43.8% versus 70.3%; P=0.047) were significantly reduced in the DS group. There was no urgent revascularization event during deferral period. Conclusions—A routine DS did not significantly reduce infarct size and MVO compared with IS, although it was safe. The beneficial effect of DS in patients with anterior myocardial infarction should be confirmed by larger randomized studies. Clinical Trial Registration—URL: http://www.clinicaltrials.gov. Unique identifier: NCT02324348.

Pioglitazone Increases Circulating MicroRNA-24 With Decrease in Coronary Neointimal Hyperplasia in Type 2 Diabetic Patients – Optical Coherence Tomography Analysis –

BACKGROUND Aberrant expression of microRNAs is associated with neointimal hyperplasia (NIH) in type 2 diabetes. We prospectively compared the effects of pioglitazone on coronary NIH and changes in microRNAs according to NIH status in type 2 diabetic patients during 9-month follow-up. METHODS AND RESULTS Type 2 diabetic patients were randomly assigned to the pioglitazone (n=36) or control groups (n=36) after coronary stenting. Primary endpoint was the comparison of changes in neointimal volume on OCT and in the level of circulating microRNA-17,-24,-92a,-126 and -145 during 9-month follow-up. Secondary endpoint was the comparison of changes in brachial artery flow-mediated dilation and inflammatory markers such as IL-6, TNF-α, hsCRP, adiponectin, sICAM-1, and sVCAM-1 between the 2 groups. Neointimal volume was significantly lower in the pioglitazone group (25.02±17.78 mm(3)vs. 55.10±30.01 mm(3), P<0.001) with significant increases in circulating microRNA-24 (0.264±0.084 vs. 0.006±0.030, P<0.001) during follow-up. FMD was significantly greater in the pioglitazone than control group at 9 months (0.47±0.14 mm vs. 0.28±0.18 mm, P<0.05, respectively). Decreases in inflammatory markers such as IL-6, TNF-α, and sVCAM-1 were significantly greater in the pioglitazone than the control group during the follow-up. CONCLUSIONS Pioglitazone significantly decreased NIH with increases in circulating microRNA-24 at 9-month follow-up. The decrease in microRNA-24 could be used as a potential predictor of increases in NIH in type 2 diabetic patients.