Jianying Ma

Myocardial transfection of hypoxia-inducible factor-1α and co-transplantation of mesenchymal stem cells enhance cardiac repair in rats with experimental myocardial infarction

IntroductionMesenchymal stem cells (MSCs) have potential for the treatment of myocardial infarction. However, several meta-analyses revealed that the outcome of stem cell transplantation is dissatisfactory. A series of studies demonstrated that the combination of cell and gene therapy was a promising strategy to enhance therapeutic efficiency. The aim of this research is to investigate whether and how the combination of overexpression of hypoxia-inducible factor-1α (HIF-1α) and co-transplantation of mesenchymal stem cells can enhance cardiac repair in myocardial infarction.MethodsWe investigated the therapeutic effects of myocardial transfection of HIF-1α and co-transplantation of MSCs on cardiac repair in myocardial infarction by using myocardial transfection of HIF-1α via an adenoviral vector. Myocardial infarction was produced by coronary ligation in Sprague-Dawley (SD) rats. Animals were divided randomly into six groups: (1) HIF-1α + MSCs group: Ad-HIF-1α (6 × 109 plate forming unit) and MSCs (1 × 106) were intramyocardially injected into the border zone simultaneously; (2) HIF-1α group: Ad-HIF-1α (6 × 109 plate forming unit) was injected into the border zone; (3) HIF-1α-MSCs group: Ad-HIF-1α transfected MSCs (1 × 106) were injected into the border zone; (4) MSCs group: MSCs (1 × 106) were injected into the border zone; (5) Control group: same volume of DMEM was injected; (6) SHAM group. Cardiac performance was then quantified by echocardiography as well as molecular and pathologic analysis of heart samples in the peri-infarcted region and the infarcted region at serial time points. The survival and engraftment of transplanted MSCs were also assessed.ResultsMyocardial transfection of HIF-1α combined with MSC transplantation in the peri-infarcted region improved cardiac function four weeks after myocardial infarction. Significant increases in vascular endothelial growth factor (VEGF) and stromal cell-derived factor-1α (SDF-1α) expression, angiogenesis and MSC engraftment, as well as decreased cardiomyocyte apoptosis in peri-infarcted regions in the hearts of the HIF-1α + MSCs group were detected compared to the MSCs group and Control group.ConclusionsThese findings suggest that myocardial transfection of HIF-1α and co-transplantation of mesenchymal stem cells enhance cardiac repair in myocardial infarction, indicating the feasibility and preliminary safety of a combination of myocardial transfection of HIF-1α and MSC transplantation to treat myocardial infarction.

High density lipoprotein cholesterol promotes the proliferation of bone-derived mesenchymal stem cells via binding scavenger receptor-B type I and activation of PI3K/Akt, MAPK/ERK1/2 pathways

High-density lipoprotein (HDL) possesses protective properties in cardiovascular diseases. However, the effect of HDL on the mesenchymal stem cells (MSCs), which could be mobilized to the damaged myocardial tissue, has not been well elucidated yet. In the current study, we investigated the effect of HDL on the proliferation of MSCs so as to reveal its molecular mechanisms. MSCs derived from rats were treated with HDL in different concentrations and for different periods. The proliferation of MSCs was measured with MTT and BrdU cell proliferation assay. The phosphorylation of Akt, ERK1/2 and the expression of p21 were evaluated by Western blotting. After the activity of respective pathways was down-regulated by the specific inhibitor and the gene of scavenger receptor-B type I (SR-BI) was knocked down by RNA interference, BrdU assay was performed to examine this effect of HDL on MSCs. We found that the proliferation of MSCs induced by HDL, in a time- and concentration-dependent manner, was the phosphorylation of Akt- and ERK1/2-dependent, which was significantly attenuated by the specific inhibitor to respective pathways. Moreover, MAPK/ERK1/2 pathway exerted a more dominating effect on this process. SR-BI contributed to HDL-induced proliferation of MSCs, which was effectively abolished by the silencing of SR-BI. The results suggested that HDL was capable of improving MSCs proliferation, in which MAPK/ERK1/2 and PI3K/Akt pathways involved and SR-BI played a critical role as well.

Automatic segmentation of calcifications in intravascular ultrasound images using snakes and the contourlet transform.

It is valuable to detect calcifications in intravascular ultrasound images for studies of coronary artery diseases. An image segmentation method based on snakes and the Contourlet transform is proposed to automatically and accurately detect calcifications. With the Contourlet transform, an original image is decomposed into low-pass bands and band-pass directional sub-bands. The 2-D Renyis entropy is used to adaptively threshold the low-pass bands in a multiresolution hierarchy to determine regions-of-interest (ROIs). Then a mean intensity ratio, reflecting acoustic shadowing, is presented to classify calcifications from noncalcifications and obtain initial contours of calcifications. The anisotropic diffusion is used in bandpass directional sub-bands to suppress noise and preserve calcific edges. Finally, the contour deformation in the boundary vector field is used to obtain final contours of calcifications. The method was evaluated via 60 simulated images and 86 in vivo images. It outperformed a recently proposed method, the Santos Filho method, by 2.76% and 14.53%, in terms of the sensitivity and specificity of calcification detection, respectively. The area under the receiver operating characteristic curve increased by 0.041. The relative mean distance error, relative difference degree, relative arc difference, relative thickness difference and relative length difference were reduced by 5.73%, 19.79%, 11.62%, 12.06% and 20.51%, respectively. These results reveal that the proposed method can automatically and accurately detect calcifications and delineate their boundaries. (E-mail: yywang@fudan.edu.cn).

REstoration of COronary flow in patients with no-reflow after primary coronary interVEntion of acute myocaRdial infarction (RECOVER)

BACKGROUND No randomized trial has been conducted to compare different vasodilators for treating no-reflow during primary percutaneous coronary intervention (PCI) for ST-segment elevation acute myocardial infarction. METHODS The prospective, randomized, 2-center trial was designed to compare the effect of 3 different vasodilators on coronary no-reflow. A total of 102 patients with no-reflow in primary PCI were randomized to receive intracoronary infusion of diltiazem, verapamil, or nitroglycerin (n = 34 in each group) through selective microcatheter. The primary end point was coronary flow improvement in corrected thrombolysis in myocardial infarction frame count (CTFC) after administration of the drug. RESULTS Compared with that of the nitroglycerin group, there was a significant improvement of CTFC after drug infusion in the diltiazem and verapamil groups (42.4 frames vs 28.1 and 28.4 frames, P < .001). The improvement in CTFC was similar between the diltiazem and verapamil groups (P = .9). Compared with the nitroglycerin group, the diltiazem and verapamil groups had more complete ST-segment resolution at 3 hours after PCI, lower peak troponin T level, and lower N-terminal pro-B-type natriuretic peptide levels at 1 and 30 days after PCI. After drug infusion, the drop of heart rate and systolic blood pressure in the verapamil group was greater than that in the diltiazem and nitroglycerin groups. CONCLUSION Intracoronary infusion of diltiazem or verapamil can reverse no-reflow more effectively than nitroglycerin during primary PCI for acute myocardial infarction. The efficacy of diltiazem and verapamil is similar, and diltiazem seems safer.

TNF-α-induced cardiomyocyte apoptosis contributes to cardiac dysfunction after coronary microembolization in mini-pigs.

This experimental study was designed to clarify the relationship between cardiomyocyte apoptosis and tumour necrosis factor‐alpha (TNF‐α) expression, and confirm the effect of TNF‐α on cardiac dysfunction after coronary microembolization (CME) in mini‐pigs. Nineteen mini‐pigs were divided into three groups: sham‐operation group (n = 5), CME group (n = 7) and adalimumab pre‐treatment group (n = 7; TNF‐α antibody, 2 mg/kg intracoronary injection before CME). Magnetic resonance imaging (3.0‐T) was performed at baseline, 6th hour and 1 week after procedure. Cardiomyocyte apoptosis was detected by cardiac‐TUNEL staining, and caspase‐3 and caspase‐8 were detected by RT‐PCR and immunohistochemistry. Furthermore, serum TNF‐α, IL‐6 and troponin T were analysed, while myocardial expressions of TNF‐α and IL‐6 were detected. Both TNF‐α expression (serum level and myocardial expression) and average number of apoptotic cardiomyocyte nuclei were significantly increased in CME group compared with the sham‐operation group. Six hours after CME, left ventricular end‐systolic volume (LVESV) was increased and the left ventricular ejection fraction (LVEF) was decreased in CME group. Pre‐treatment with adalimumab not only significantly improved LVEF after CME (6th hour: 54.9 ± 2.3% versus 50.4 ± 3.9%, P = 0.036; 1 week: 56.7 ± 4.2% versus 52.7 ± 2.9%, P = 0.041), but also suppressed cardiomyocyte apoptosis and the expression of caspase‐3 and caspase‐8. Meanwhile, the average number of apoptotic cardiomyocytes nuclei was inversely correlated with LVEF (r = −0.535, P = 0.022). TNF‐α‐induced cardiomyocyte apoptosis is likely involved in cardiac dysfunction after CME. TNF‐α antibody therapy suppresses cardiomyocyte apoptosis and improves early cardiac function after CME.

Changes in left ventricular ejection fraction and coronary flow reserve after coronary microembolization

Introduction Although coronary microembolization (CME) is a frequent phenomenon in patients undergoing percutaneous coronary intervention, few data are available on the changes in left ventricular ejection fraction (LVEF) and coronary flow reserve (CFR) after CME. Material and methods In this study, six miniature swine of either sex (body weight 21-25 kg) were used to prepare a CME model. After coronary angiography, 1.2 × 105 microspheres (42 µm) were selectively infused into the left anterior descending artery via an infusion catheter. Left ventricular ejection fraction was evaluated using transthoracic echocardiography; myocardial blood flow was measured using coloured microspheres; and CFR and coronary pressure were measured using Doppler and a pressure wire. Results Left ventricular ejection fraction was 0.77 ±0.08 at baseline, 0.69 ±0.08 at 2 h, 0.68 ±0.08 at 6 h, and 0.76 ±0.06 at 1 week (2 h vs. baseline p < 0.05; 6 h vs. baseline p < 0.01). After CME, left ventricular end systolic volume (LVESV) and end diastolic volume (LVEDV) were significant larger 1 week later (p < 0.01 for both), while CFR was significantly reduced at 6 h (1.24 ±0.10 at 6 h vs. 1.77 ±0.30 at baseline, p < 0.01) and myocardial blood flow remained unchanged. Serum ET-1 level was significantly higher only at 6 h after CME (6 h vs. baseline p < 0.05). Conclusions Reduction of CFR and LVEF is significant at 6 h after CME and recovers 1 week later with left ventricular dilation.

Role of KCa3.1 Channels in Macrophage Polarization and Its Relevance in Atherosclerotic Plaque Instability

Objective— Emerging evidence indicates that proinflammatory macrophage polarization imbalance plays a key role in atherosclerotic plaque progression and instability. The calcium-activated potassium channel KCa3.1 is critically involved in macrophage activation and function. However, the role of KCa3.1 in macrophage polarization is unknown. This study investigates the potential role of KCa3.1 in transcriptional regulation in macrophage polarization and its relationship to plaque instability. Approach and Results— Human monocytes were differentiated into macrophages using macrophage colony-stimulating factor. Macrophages were then polarized into proinflammatory M1 cells by interferon-&ggr; and lipopolysaccharide and into alternative M2 macrophages by interleukin-4. A model for plaque instability was induced by combined partial ligation of the left renal artery and left common carotid artery in apolipoprotein E knockout mice. Significant upregulation of KCa3.1 expression was observed during the differentiation of human monocytes into macrophages. Blocking KCa3.1 significantly reduced the expression of proinflammatory genes during macrophages polarization. Further mechanistic studies indicated that blocking KCa3.1 inhibited macrophage differentiation toward the M1 phenotype by downregulating signal transducer and activator of transcription-1 phosphorylation. In animal models, KCa3.1 blockade therapy strikingly reduced the incidence of plaque rupture and luminal thrombus in carotid arteries, decreased the expression of markers associated with M1 macrophage polarization, and enhanced the expression of M2 markers within atherosclerotic lesions. Conclusions— These results suggest that blocking KCa3.1 suppresses plaque instability in advanced stages of atherosclerosis by inhibiting macrophage polarization toward an M1 phenotype.

Sirolimus- versus paclitaxel-eluting stents for coronary bifurcations intervention: a meta-analysis of five clinical trials.

Backgrounds: Relative efficacy and safety of sirolimus‐eluting stents (SES) compared with paclitaxel‐eluting stents (PES) remains controversial. It is unknown whether there are different effect and safety in coronary bifurcation treatment between SES and PES. Objectives: The meta‐analysis was performed to compare the clinical outcomes of SES and PES in coronary bifurcation intervention. Methods: Five head‐to‐head clinical trials of SES versus PES in coronary bifurcation intervention were included. A total of 2,567 patients were involved in the meta‐analysis. Mean follow‐up period ranged from 6 to 35 months. The primary end points were the need for target lesion revascularization (TLR) and main‐branch restenosis. Secondary end points were target vessel revascularization (TVR), cardiac death, major adverse cardiac events (MACE), and stent thrombosis. Results: Compared with PES, SES significantly reduced the risk of TLR (5.3% vs. 10.6%, odds ratio (OR) 0.52; 95% confidence interval (CI) = 0.38–0.70, P < 0.001), main‐branch restenosis (4.59% vs. 12.59%, OR 0.31; 95% CI = 0.18–0.55, P < 0.001) and TVR (7.05% vs. 12.57%, OR 0.58; 95% CI = 0.42–0.81, P = 0.001) in coronary bifurcation intervention. In addition, SES group also had a significantly lower incidence of MACE (8.20% vs. 14.13%, OR 0.58; 95% CI = 0.40–0.84, P = 0.004) than PES group. However, there were no statistical difference with respect to the incidence of cardiac death (1.64% vs. 1.09%, P = 0.19) and stent thrombosis (0.84% vs. 1.08%, P = 0.64) between SES and PES groups. Conclusions: Compared with PES, SES reduced the incidence of TLR, main‐branch restenosis and MACE in coronary bifurcation intervention, while the risk of stent thrombosis was similar between SES and PES groups.

Addition of cilostazol to conventional dual antiplatelet therapy reduces the risk of cardiac events and restenosis after drug-eluting stent implantation: a meta-analysis.

This meta‐analysis was performed to compare the risk of cardiac events and restenosis between triple antiplatelet therapy (TAT, addition of cilostazol to aspirin and clopidogrel) and conventional dual antiplatelet therapy (DAT, aspirin and clopidogrel) in drug‐eluting stents (DES) implantation patients. We performed PUBMED, MEDLINE, EMBASE, and Cochrane CENTRAL searches for randomized clinical trials of TAT versus DAT in patients after DES implantation. Five clinical trials were involved in the study. TAT was associated with a 36% reduction in major adverse cardiac events (MACE; odds ratio (OR) = 0.64; 95% confidence interval (CI) = 0.51–0.81, P < .01), a 40% reduction (OR = 0.60, 95% CI = 0.44–0.80; P < .01) in target vessel revascularization (TVR), a 44% reduction (OR = 0.56, 95% CI = 0.34–0.91; P = .02) in target lesion revascularization (TLR) and a 47%/44% reduction in in‐segment/in‐stent restenosis (P < .01) and lower in‐segment/in‐stent late loss (P < .01). As regards to the safety assessment, there was no significant difference about the risk of stent thrombosis and bleeding between TAT and DAT group, while the risk of gastrointestinal trouble was significantly higher in TAT group (OR = 2.46, 95% CI = 1.25–4.86; P < .01). Addition of cilostazol to DAT reduced the incidence of MACE, TVR, and TLR after DES implantation. TAT also reduced the risk of restenosis and late loss in patients after DES implantation.

Glucocorticoid ameliorates early cardiac dysfunction after coronary microembolization and suppresses TGF-β1/Smad3 and CTGF expression

OBJECTIVES This study was designed to evidence the protective effect of glucocorticoid therapy on cardiac dysfunction after coronary microembolization (CME), and to clarify its mechanism with the expression of transforming growth factor-beta 1 (TGF-β1)/Smad3 and connective tissue growth factor (CTGF). METHODS Eighteen mini-pigs were studied, including Sham-operation group (n=4), CME group (n=8) and Glucocorticoid therapy group (n=6, received methylprednisolone 25mg/kg intravenously 30 min before CME). Magnetic resonance imaging (3.0-T) was performed at baseline, 6th hour and one week after operation to evaluate cardiac function. Serum TGF-β1, CTGF and troponin T were also detected. Myocardial expressions of TGF-β1, CTGF and Smad3 were detected by western blot and immunohistochemistry. Total collagen expression was demonstrated by Masson Trichrome stain. RESULTS Compared with Sham-operation group, left ventricular end-systolic volume (LVESV) and left ventricular end-diastolic volume (LVEDV) in CME group were increased at 6th hour after CME, while left ventricular ejection fraction (LVEF) was decreased significantly. Compared with CME group, methylprednisolone greatly improved LVEF after CME (6th hour: 56.0 ± 3.2% vs. 51.8 ± 3.8%, P=0.030; one week: 57.8 ± 3.2% vs. 54.6 ± 2.6%, P=0.053). We found that methylprednisolone not only significantly decreased serum TGF-β1, CTGF and troponin T, but also reduced myocardial expressions of TGF-β1, CTGF and Smad3 after CME. In addition, collagen volume fraction in glucocorticoid therapy group was markedly lower than that in CME group. CONCLUSIONS Glucocorticoid therapy could improve early cardiac function after CME, and its mechanism could be associated with TGF-β1/Smad3 and CTGF suppression.