Correlation Between Serum Uric Acid Levels and Coronary Plaque Characteristics on Optical Coherence Tomography.

Elevated serum uric acid (sUA) is associated with increasing risk of coronary heart disease (CHD). However, existing research is limited by potential confounders. Herein, our study aims to probe the association between sUA levels and the morphological characteristics of coronary plaque by a propensity score matching (PSM) analysis.All 420 patients with CHD who had undergone optical coherence tomography of culprit lesions were included. Eligible patients were assigned into 2 groups according to sUA level: high-sUA group (sUA ≥ 6.0 mg/dL) and low-sUA group (sUA < 6.0 mg/dL). PSM was applied to control the balance of baseline characteristics.After PSM, a total of 112 patients were included in our study (56 in each group). The high-sUA group showed a higher prevalence of TCFA (35.7% versus 16.1%, P = 0.03) and macrophage infiltration (33.9% versus 14.3%, P = 0.026) compared with the low-sUA group. Plaques in the high-sUA group had a wider maximum lipid arc (166.51° (115.77°, 224.14°) versus 142.29° (93.95°, 169.06°), P = 0.048), longer calcification length (6.77 (3.90, 20.55) mm versus 4.20 (1.95, 7.45) mm, P = 0.040), and thinner minimum fibrous cap thickness (43.81 (28.17, 62.26) µm versus 92.57 (46.25, 135.37) µm, P = 0.003). Correlation analysis indicated that the sUA value was inversely associated with the minimum fibrous cap thickness (r = -0.332, P = 0.015) and positively associated with the maximum lipid arc (r = 0.399, P = 0.003), average lipid arc (r = 0.347, P = 0.011), and calcification length (r = 0.386, P = 0.006).The relationship between high-sUA levels and typical vulnerable features of plaques persisted after balancing the traditional risk factors.

Expression of farnesyl pyrophosphate synthase is increased in diabetic cardiomyopathy.

Farnesyl pyrophosphate synthase (FPPS)-catalyzed isoprenoid intermediates are involved in diabetic cardiomyopathy. This study investigated the specific role of FPPS in the development of diabetic cardiomyopathy. We demonstrated that FPPS expression was elevated in both in vivo and in vitro models of diabetic cardiomyopathy. FPPS inhibition decreased the expression of proteins related to cardiac fibrosis and cardiomyocytic hypertrophy, including collagen I, collagen III, connective tissue growth factor, natriuretic factor, brain natriuretic peptide, and ß-myosin heavy chain. Furthermore, FPPS inhibition and knockdown prevented phosphorylated c-Jun N-terminal kinase 1/2 (JNK1/2) activation in vitro. In addition, a JNK1/2 inhibitor downregulated high-glucose-induced responses to diabetic cardiomyopathy. Finally, immunofluorescence revealed that cardiomyocytic size was elevated by high glucose and was decreased by zoledronate, small-interfering farnesyl pyrophosphate synthase (siFPPS), and a JNK1/2 inhibitor. Taken together, our findings indicate that FPPS and JNK1/2 may be part of a signaling pathway that plays an important role in diabetic cardiomyopathy.

Effect of Shexiang Tongxin dropping pill on stable coronary artery disease patients with normal fractional flow reserve and coronary microvascular disease: A study protocol.

INTRODUCTION: Coronary microvascular disease (CMVD) can affect the structure, function, and metabolism of the heart, and has an important impact on the occurrence, development and prognosis of coronary artery disease (CAD). Shexiang Tongxin dropping pill (STDP) can dilate blood vessels, alleviate inflammation, reduce endothelial damage, and improve coronary microvascular function in mice with myocardial infarction. This study aims to assess the impact of STDP on stable coronary artery disease (SCAD) patients with normal FFR and CMVD. METHODS AND ANALYSIS: This is a single-center, prospective randomized trial that will enroll 64 SCAD patients, CAD with normal FFR and CMVD. Patients will be randomly divided into study group and control group in a 1:1 fashion. On the basis of conventional drug treatment, the former will receive STDP while the latter will not. The follow-up period of the subjects is 12 months, and clinical follow-up will be conducted before discharge, 30 days, 3 months, 6 months, and 12 months after procedure to complete the detection of relevant indicators. The primary endpoint is the change of index of microcirculatory resistance (ΔIMR) at 12-month follow-up. DISCUSSION: The present study will be the first randomized control study to evaluate the efficacy and safety of STDP on SCAD patients, CAD with normal FFR and CMVD, which will provide a broader idea and more experimental basis for improving the treatment of CMVD. TRIAL REGISTRATION: This is a protocol for the randomized clinical trial which has been registered in the Chinese clinical Trial Registry with an identifier: ChiCTR2000032429.

Bone marrow mesenchymal stem cell-secreted exosomes carrying microRNA-125b protect against myocardial ischemia reperfusion injury via targeting SIRT7.

MicroRNA-125b (miR-125b) reduces myocardial infarct area and restrains myocardial ischemia reperfusion injury (I/R). In this study, we aimed to investigate the effect of bone marrow mesenchymal stem cell (BMSC)-derived exosomes carrying miR-125b on I/R rats. The myocardial I/R model in rats was constructed by ligation of the left anterior descending coronary artery (LAD). Rats were randomly divided into I/R and Sham group. Lv-cel-miR-67 (control) or Lv-miR-125b was transfected into BMSCs. Exosomes were extracted from transfected BMSCs, and separately named BMSC-Exo-67, BMSC-Exo-125b, and BMSC-Exo. MTT assay and flow cytometry were used to detect the viability and apoptosis of I/R myocardium cells, respectively. The expression of cell apoptosis proteins and the levels of inflammatory factors were examined by Western blot and ELISA assay, respectively. The target relationship between miR-125b and SIRT7 was predicted by using StarBase3.0, and was confirmed by using dual-luciferase reporter gene assay. qRT-PCR, immunohistochemistry staining, and Western blot were used to evaluate the expression of SIRT7 in myocardium tissues in I/R rats. BMSC-derived exosomes were successfully isolated and identified by TEM and positive expression of CD9 and CD63. The expression of miR-125b was down-regulated in I/R myocardium tissues and cells. BMSC-Exo-125b significantly up-regulated miR-125b in I/R myocardium cells. The intervention of BMSC-Exo-125b significantly increased the cell viability, decreased the apoptotic ratio, down-regulated Bax and caspase-3, up-regulated Bcl-2, and decreased the levels of IL-1ß, IL-6, and TNF-α in I/R myocardium cells. SIRT7 was a target of miR-125b, and BMSC-Exo-125b significantly down-regulated SIRT7 in myocardium cells. In addition, the injection of BMSC-Exo-125b alleviated the pathological damages and down-regulated SIRT7 in myocardium tissues of I/R rats. BMSC-derived exosomes carrying miR-125b protected against myocardial I/R by targeting SIRT7.

Inhibition of microRNA-34a mediates protection of thymosin beta 4 in endothelial progenitor cells against advanced glycation endproducts by targeting B-cell lymphoma 2.

The aim of our work was to test whether thymosin beta 4 protected endothelial progenitor cells against apoptosis induced by advanced glycation endproducts and investigate the underlying mechanism. Treatment with thymosin beta 4 or transfection with microRNA-34a inhibitor enhanced cell viability, reduced apoptosis, abated oxidative stress, and attenuated mitochondrial dysfunction in endothelial progenitor cells exposed to advanced glycation endproducts. Incubation with advanced glycation endproducts led to increased levels of microRNA-34a, which was attenuated by treatment with thymosin beta 4. Transfection with microRNA-34a reversed the beneficial effect of thymosin beta 4 against injuries induced by advanced glycation endproducts. The microRNA-34a could directly bind to the 3'UTRs of the mRNA of B-cell lymphoma 2, and thymosin beta 4 treatment upregulated B-cell lymphoma 2 expression in endothelial progenitor cells exposed to advanced glycation endproducts. More importantly, knockdown of B-cell lymphoma 2 abolished the protection of thymosin beta 4 and microRNA-34a inhibitor against advanced glycation endproducts. In conclusion, inhibition of microRNA-34a mediated protection of thymosin beta 4 in endothelial progenitor cells against advanced glycation endproducts by targeting B-cell lymphoma 2, which was helpful for understanding the therapeutic potential of thymosin beta 4 for diabetic patients.

Theaflavin 3,3'-digallate reverses the downregulation of connexin 43 and autophagy induced by high glucose via AMPK activation in cardiomyocytes.

Theaflavin 3,3'-digallate (TF3), is reported to protect cardiomyocytes from lipotoxicity and reperfusion injury. However, the role of TF3 in the protection of high-glucose injury is still poorly understood. This study investigated the protective effects of TF3 on gap junctions and autophagy in neonatal cardiomyocytes (NRCMs). NRCMs preincubated with high glucose were coincubated with TF3. The expression of connexins and autophagy-related proteins was determined. The functioning of gap-junctional intercellular communication (GJIC) was measured by a dye transfer assay. Adenosine monophosphate-activated protein kinase (AMPK) activity was determined by western blot. Moreover, AMPK was activated with aminoimidazole-4-carboxamide-1-ß-d-ribofuranoside (AICAR) or inhibited by AMPKα small interfering RNA (siRNA) to explore the role of AMPK in the modulation of connexin 43 (Cx43) and autophagy. Meanwhile, autophagy was activated or blocked to observe the change in Cx43 expression. It was found that the protein expression of Cx43 and autophagy-related proteins was increased in a TF3 dose- and time-dependent manner under high glucose. TF3 also recovered the reduced GJIC function induced by high glucose concentrations. TF3 activated phosphorylated AMPK in a time-dependent way. AMPKα siRNA abrogated the protection of TF3, while AICAR showed similar results compared to the TF3 treatment. Meanwhile, autophagy activation caused decreased Cx43, while cotreatment with baf A1 enhanced Cx43 expression further compared with the TF3 treatment alone under high glucose. We concluded that TF3 partly reversed the inhibition of Cx43 expression and autophagy induced by high glucose in NRCMs, partly by restoring AMPK activity. Inhibition of autophagy might be protective by preserving Cx43 expression in NRCMs stimulated by high glucose.

Thymosin ß4 promotes glucose-impaired endothelial progenitor cell function via Akt/endothelial nitric oxide synthesis signaling pathway.

Circulating endothelial progenitor cells (EPCs) are a subtype of hematopoietic stem cells, which can differentiate into endothelial cells and restore endothelial function. However, high glucose decreases the number and impairs the function of EPCs. A previous study showed that thymosin ß4 (Tß4), a pleiotropic peptide beneficial for multiple functions of various types of cells, could promote EPC migration and dose-dependently upregulate the phosphorylation of Akt and endothelial nitric oxide synthesis signaling (eNOS). In present study, the hypothesis that Tß4 can improve glucose-suppressed EPC functions via the Akt/eNOS signaling pathway and restores the production of nitric oxide (NO) is investigated. EPCs were isolated from the peripheral blood of healthy volunteers and formed a cobblestone shape after 3-4 weeks of cultivation. Then, EPCs were treated with high concentrations of glucose (25 mM) for 4 days and administrated with Tß4 for further study. Transwell migration and tube formation assays were performed to access the migratory and angiogenic ability of EPCs. In addition, the quantity of Akt, eNOS and the concentration of nitric oxide (NO) was investigated. Functional studies showed that high concentrations of glucose significantly suppressed EPC function, while this adverse effect was reversed by the administration of Tß4. In addition, Akt small interfering (si)RNA and eNOS siRNA were demonstrated to reduce the protective effect of Tß4 against glucose-impaired EPC functions. These findings suggest that Tß4 improves glucose-impaired EPC functions via the Akt/eNOS signaling pathway.

Apelin Ameliorates High Glucose-Induced Downregulation of Connexin 43 via AMPK-Dependent Pathway in Neonatal Rat Cardiomyocytes.

Diabetes Mellitus is a common disorder, with increasing risk of cardiac arrhythmias. Studies have shown that altered connexin expression and gap junction remodeling under hyperglycemia contribute to the high prevalence of cardiac arrhythmias and even sudden death. Connexin 43 (Cx43), a major protein that assembles to form cardiac gap junctions, has been found to be downregulated under high glucose conditions, along with inhibition of gap junctional intercellular communication (GJIC). While, apelin, a beneficial adipokine, increases Cx43 protein expression in mouse and human embryonic stem cells during cardiac differentiation. However, it remains unknown whether apelin influences GJIC capacity in cardiomyocytes. Here, using Western blotting and dye transfer assays, we found that Cx43 protein expression was reduced and GJIC was impaired after treatment with high glucose, which, however, could be abrogated after apelin treatment for 48 h. We also found that apelin increased Cx43 expression under normal glucose. Real-time PCR showed that the Cx43 mRNA was not significantly affected under high glucose conditions in the presence of apelin or high glucose and apelin. High glucose decreased the phosphorylation of AMPKα; however, apelin activated AMPKα. Interestingly, we found that Cx43 expression was increased after treatment with AICAR, an activator of AMPK signaling. AMPKα inhibition mediated with transfection of siRNA-AMPKα1 and siRNA-AMPKα2 abolished the protective effect of apelin on Cx43 expression. Our data suggest that apelin attenuates high glucose-induced Cx43 downregulation and improves the loss of functional gap junctions partly through the AMPK pathway.

High glucose and free fatty acids induce endothelial progenitor cell senescence via PGC-1α/SIRT1 signaling pathway.

The objective of the research was to investigate the function of endothelial progenitor cells (EPCs) in the conditions of high glucose and lipids, which has been widely used to mimic the metabolic disorder that occurs in type 2 diabetic mellitus, and further to verify the role of PGC-1α and SIRT1, cellular energy metabolism regulators, in the process of senescence of EPCs with these combined stimuli. Circulating EPCs were incubated in absence or presence of high glucose (25 mM), FFA (200 µM) or both. EPCs senescence was assessed by ß-galactosidase staining, EPCs telomerase activity was measured by telomeric repeat ampli-fication protocol assay, in vitro angiogenesis assay and MTT assays were performed to assess angiogenesis and proliferation ability of EPCs. The results showed that combined stimuli inhibited EPCs reendothelialization ability in vitro, accelerated EPCs senescence and decreased the telomerase activity. Meanwhile, with combined stimuli, the expression of PGC-1α increased whereas SIRT1 expression decreased in EPCs accompanied by activation of P53/P21 signaling pathway. Conversely, transfection of EPCs with PGC-1α-siRNA rescued EPCs premature senescence and up-regulated SIRT1 and decreased P53/P21 expression, correlating closely with the down-regulation of PGC-1α itself. In addition, the combined stimuli induced up-regulation of PGC-1α expression was partly mediated by ROS and P38 signaling pathway. Overall, the data presented here identify PGC-1α as a potent negative regulator of EPCs' senescence under combined stimuli, which is partly mediated by SIRT1/P53/P21 signaling pathway.

The Impact of Rosuvastatin on the Density Score of Coronary Artery Calcification in Coronary Artery Disease Patients with Type 2 Diabetes Mellitus: Rationale and Design of RosCal Study.

INTRODUCTION: More and more evidence suggests that the density of calcification plays an important role in the plaque stability. However, few studies have investigated the statin treatment on the density of plaque calcification in patients with both coronary artery disease (CAD) and type 2 diabetes mellitus. METHODS: One hundred and twenty-two CAD patients with type 2 diabetes with confirmed coronary artery calcification (CAC) will be recruited consecutively in a 12-month period. These patients will receive rosuvastatin (20 mg/day) therapy in the next 24 months. Blood tests and adverse events will be collected at routine follow-up of 1, 3, 6, 12, 18 and 24 months. The primary endpoint will be the change of CAC density score measured by coronary CT angiography after 24 months' treatment of rosuvastatin (20 mg/day) compared with baseline. The secondary endpoints will be the change of serum sclerostin and the effect on the volume score of CAC in those patients. RESULTS: We expect that rosuvastatin could both increase the density of CAC to improve plaque stability and up-regulate serum sclerostin, which would suggest the underlying mechanism of the plaque stabilization by a statin. CONCLUSION: This study would be the first to demonstrate the impact of rosuvastatin on the density score of coronary artery calcification in CAD patients with type 2 diabetes. This study has been registered in ClinicalTrials.gov (NCT02418884).

Prevalence and Clinical Impact of Tissue Protrusion After Stent Implantation: An ADAPT-DES Intravascular Ultrasound Substudy.

OBJECTIVES: The aim of this study was to evaluate the prevalence and long-term clinical impact of tissue protrusion (TP) after stent implantation. BACKGROUND: Stent implantation may be associated with tissue (plaque or thrombus) protrusion, especially in unstable lesions, but its clinical impact is unknown. METHODS: ADAPT-DES (Assessment of Dual Antiplatelet Therapy With Drug-Eluting Stents) was a prospective multicenter study of 8,663 patients undergoing percutaneous coronary intervention (PCI) using drug-eluting stents. In a pre-specified intravascular ultrasound (IVUS) substudy, 2,072 patients with 2,446 culprit lesions underwent post-PCI IVUS (among whom some also underwent pre-PCI IVUS) and were classified according to the presence or absence of post-stent TP. RESULTS: After PCI, 34.3% of lesions displayed TP on IVUS. Median maximum TP was 0.7 mm(2) (interquartile range: 0.5 to 1.2 mm(2)) in area and 3.0 mm (interquartile range: 1.4 to 6.7 mm) in length. Patients with TP more often presented with ST-segment elevation myocardial infarction or non-ST-segment elevation myocardial infarction but less often with unstable angina or stable ischemic heart disease. In 893 culprit lesions that were also examined pre-PCI, TP was associated with larger reference luminal area, greater plaque burden, and more plaque ruptures, attenuated plaque, and virtual histology thin-cap fibroatheromas. Because a larger stent or post-dilation balloon was used, post-PCI luminal area was significantly larger in lesions with versus without TP. At 2-year follow-up, there was less clinically driven target lesion revascularization in lesions with TP and no significant difference in major adverse cardiac events (defined as cardiac death, myocardial infarction, or stent thrombosis) in patients with versus without TP. CONCLUSIONS: IVUS-detected TP after drug-eluting stent implantation was not associated with worse long-term clinical outcomes, in part because of greater stent expansion in lesions with TP.

Increased coronary lipid accumulation in heart transplant recipients with prior high-grade cellular rejection: novel insights from near-infrared spectroscopy.

Cardiac allograft vasculopathy is a major cause of morbidity and mortality among patients after heart transplantation. We sought to assess the amount of lipid accumulation in the coronary arteries of transplant patients according to rejection grade. Overall, 39 consecutive heart transplant recipients undergoing annual routine surveillance coronary angiography underwent near-infrared spectroscopy and intravascular ultrasound imaging of 1 coronary artery. Rejection history was graded according to the International Society of Heart and Lung Transplantation (ISHLT) classification as none/mild/moderate-grade rejection (ISHLT 0, 1A/1B, or 2) compared to high-grade rejection (≥3A). Patients with prior history of high-grade rejection had larger plaque burden in the distal coronary segments [45.7 % (25.5-63.7) vs 25.1 % (19.9-37.8), p = 0.02] and a higher maximum lipid core burden index in any 4-mm long segment (maxLCBI(4mm)) [243 (91-400) vs 41 (1-170), p = 0.016] as compared with patients with prior history of none/mild/moderate-grade rejection. By multivariable linear regression analysis, prior history of high-grade rejection was an independent predictor for maxLCBI(4mm). A maxLCBI(4mm) >200 distinguished prior history of high-grade from none/mild/moderate rejection with a sensitivity of 61.5 % and specificity of 84.6 %. The current study demonstrates that the coronary arteries of post heart-transplant patients with a prior history of high-grade cellular rejection have increasing amounts of lipid-rich plaque. MaxLCBI(4mm) >200 might differentiate patients with previous high-grade cellular rejection from heart transplant recipients with none/mild/moderate-grade rejection.

Impact of intracoronary injection of CD133+ bone marrow stem cells on coronary atherosclerotic progression in patients with STEMI: a COMPARE-AMI IVUS substudy.

OBJECTIVES: Adverse effects of intracoronary injection of stem cells on in-stent restenosis and atherosclerotic progression remain unclear. We sought to evaluate the adverse effects of intracoronary injection of CD133 cells on in-stent restenosis and atherosclerotic progression in the infarct-related and contralateral arteries using serial intravascular ultrasound (IVUS) analysis. METHODS: Baseline and 4-month follow-up IVUS images were obtained from 17 patients treated with intracoronary stem cell injection and 20 placebo patients after primary percutaneous coronary intervention in the COMPARE-AMI trial. In the infarct-related artery, the stented segment, 5 mm proximal and distal reference segments, and proximal and distal nonstented segments were analyzed every 1 mm; the entire segment of a contralateral artery was also analyzed every 1 mm. RESULTS: In the infarct-related artery analysis, the median percentage of in-stent neointimal hyperplasia (12.1 vs. 7.6%, P=0.95), the reduction in the minimum lumen area (MLA; -1.6 vs. -1.5 mm(2), P=0.97), and the MLA at follow-up (4.3 vs. 5.3 mm(2), P=0.21) were found to be similar between the stem cell and placebo groups. Changes in proximal and distal nonstented segment lumen areas and plaque burden were also similar between the stem cell and placebo groups; however, there was a decrease in the maximum arc of the attenuated plaque behind the stent from baseline to follow-up in the placebo group (P=0.004), but not in the stem cell group. In the contralateral artery, there were no differences in changes in MLA, plaque burden, or attenuated plaque between stem cell and placebo patients. CONCLUSION: Intracoronary injection of CD133(+) bone marrow stem cells has no IVUS-detectable effect on neointimal hyperplasia or atherosclerosis progression in either infarct-related or contralateral arteries.

In vivo comparison between cardiac allograft vasculopathy and native atherosclerosis using near-infrared spectroscopy and intravascular ultrasound.

AIMS: The aim was to compare cardiac allograft vasculopathy to native atherosclerosis by near-infrared spectroscopy-intravascular ultrasound (NIRS-IVUS). METHODS AND RESULTS: Twenty-seven atherosclerotic (non-transplant) patients and 28 heart transplant recipients undergoing routine surveillance coronary angiography underwent NIRS-IVUS imaging of the left anterior descending coronary artery. In each proximal, middle, and distal coronary artery segment, the maxLCBI4mm [4-mm long segment with maximum lipid core burden index (LCBI)] and corresponding IVUS parameters were compared. MaxLCBI4mm was significantly greater among atherosclerotic patients than the transplant patients in both proximal and middle coronary artery segments, but not in the distal segment. There was a positive linear correlation between maxLCBI4mm and maximum plaque burden in both groups, but atherosclerotic patients demonstrated a smaller maxLCBI4mm than transplant recipients among segments with plaque burden <40%. Among segments with a maximum plaque burden ≥40%, native-atherosclerosis patients had a greater maxLCBI4mm compared with transplant patients (P = 0.015). Calcification was present in 72.9% of native atherosclerosis and 14.7% of transplant segments (P< 0.001). Among the 165 analysed segments, prevalence of lipid-rich plaque (LRP) with superficial attenuation (30.9 vs. 1.2%, P < 0.001) or calcified LRP (13.6 vs. 2.4%, P = 0.03) was significantly greater in native atherosclerosis compared with transplant patients. Conversely, the proportion of segments with non-LRP (46.4 vs. 11.1%, P < 0.001) was higher in transplant patients. CONCLUSION: NIRS-IVUS imaging demonstrated early and accelerated lipid accumulation with smaller plaque burden and less calcium in patients after heart transplant when compared with patients with native atherosclerosis.

Thymosin ß4 activates integrin-linked kinase and decreases endothelial progenitor cells apoptosis under serum deprivation.

Thymosin ß4 (Tß4) has been suggested to regulate multiple cell signal pathways and a variety of cellular functions such as cell migration, proliferation, survival, and angiogenesis. Here, we investigated the effect of Tß4 on endothelial progenitor cells (EPCs) apoptosis induced by serum deprivation and the corresponding signal transduction pathways involved in this process. Circulating EPCs, isolated from healthy volunteers, were cultured in the absence or presence of Tß4 and various signal cascade inhibitors. Apoptosis was evaluated with Annexin V immunostaining and cytosolic cytochrome c expression. Incubation of EPCs with Tß4 caused a concentration dependent increase in cell viability and proliferation activity. It also caused an inhibitory effect on EPCs apoptosis, which was abolished by PI3K inhibitors (either LY294002 or Wortmannin) or JNK MAPK inhibitor SP600125. In addition, the expression and activity of caspase-3 and -9 were decreased by Tß4, which markedly increased the Bcl-2/Bax ratio within EPCs. Furthermore, Tß4 was immunoprecipitated with integrin-linked kinase (ILK), accompanied by augmentation of ILK activity. Transfection of EPCs with ILK-siRNA resulted in abolishment of the activation of ILK-Akt and the ameliorative effect on apoptosis by Tß4. Together, Tß4 mediated inhibitory effect on EPCs apoptosis under serum deprivation can be attributed, at least in part, to ILK-Akt activation. The activation of JNK MAPK might also be involved in this process.

Down-regulation of connexin43 gap junction by serum deprivation in human endothelial cells was improved by (-)-Epigallocatechin gallate via ERK MAP kinase pathway.

Intercellular communication through gap junctions (GJIC) plays an essential role in maintaining the functional integrity of vascular endothelium. Despite emerging evidence suggests that (-)-Epigallocatechin gallate (EGCG) may improve endothelial function. However, its effect on Cx43 gap junction in endothelial cells remains unexplored. Here we investigated the effect of EGCG on connexin43 (Cx43) gap junction in endothelial cells. The levels of Cx43 protein in human umbilical vein endothelial cells (HUVECs) cultured under serum-deprivation 48 h decreased about 50%, accompanied by decreased GJIC. This reduction can be reversed by treatments with EGCG. In addition, EGCG activated ERK, P38, and JNK mitogen-activated protein kinases (MAPKs), which were supposed to participate in the regulation of Cx43. A MEK inhibitor PD98059, but not SB203580 (a p38 kinase inhibitor) or SP600125 (a JNK kinase inhibitor), abolished the effects of EGCG on Cx43 expression and GJIC. Moreover, although both Akt and eNOS phosphorylation were time-dependently augmented by EGCG, neither PI3K inhibitor LY294002 nor eNOS inhibitor L-NAME blocked the effects of EGCG on Cx43 gap junctions. Thus, EGCG attenuated Cx43 down-regulation and impaired GJIC induced by serum deprivation, ERK MAPK Signal transduction pathway appears to be involved in these processes.

Heparin/collagen multilayer as a thromboresistant and endothelial favorable coating for intravascular stent.

Endothelialization and antithrombogenicity are two key issues in stent implantation. The layer-by-layer (LbL) deposition of anticoagulant heparin and cell compatible collagen was explored to develop a multilayered coating with synergic property of antithrombogenicity and fast endothelialization. The quartz crystal microbalance with dissipation (QCM-D), UV spectrometer, spectroscopic ellipsometry, scanning electron microscopy, and confocal laser scanning microscopy investigations indicate that the LbL technique, which based on molecular assembly, provides an easy way to develop a smooth, homogenous, and stable coating onto stents. In vitro blood clotting time tests and the platelet adhesion tests show that the multilayer-modified stents present good hemocompatibility. In vitro endothelial cell (EC) culture results show that the multilayer-modified surfaces accelerate the adhesion and proliferation of ECs. These results illustrate that a stent surface coating with properties of antithrombogenicity and EC preference was obtained via heparin/collagen multilayer modification. This surface coating may have great potential in facilitating in situ endothelialization of blood contacting materials.

Stromal cell-derived factor 1alpha reduces senescence of endothelial progenitor subpopulation in lectin-binding and DiLDL-uptaking cell through telomerase activation and telomere elongation.

Recent studies have suggested that reduced endothelial progenitor subpopulation in lectin-binding and DiLDL-uptaking cell (EPC subpopulation) number and activity was associated with EPC subpopulation senescence that involved telomerase activity and telomere length. Stromal cell-derived factor-1alpha (SDF-1alpha) has been shown to augment a variety of cellular functions of EPC subpopulation and subsequently contribute to ischemic neovascularization. Therefore, we investigated whether SDF-1alpha might be able to prevent senescence of EPC subpopulation and also investigated the effects of SDF-1alpha on the telomerase activity and telomere length. EPC subpopulation were isolated from peripheral blood and characterized. After ex vivo prolonged cultivation, EPC subpopulation became senescent as determined by acidic beta-galactosidase staining. SDF-1alpha dose-dependently inhibited the onset of EPC subpopulation senescence. Moreover, SDF-1alpha increased proliferation and colony-forming activity of EPC subpopulation. SDF-1alpha also increased telomerase activity and telomere length, which was accompanied with upregulation of the catalytic subunit, telomerase reverse transcriptase (TERT). Whereas these effects of SDF-1alpha on telomerase activity and expression of hTERT mRNA were significantly attenuated by CXCR4-specific peptide antagonist (AMD3100) and phosphoinositide 3-kinase (PI3K) inhibitor (LY294002). In conclusions, SDF-1alpha delays the onset of EPC subpopulation senescence, which may be related to the activation of telomerase and elongation of telomere length. The inhibition of EPC subpopulation senescence and induction of EPC subpopulation proliferation by SDF-1alpha in vitro may importantly improve the functional activity of EPC subpopulation for potential cell therapy.

In situ endothelialization of intravascular stents coated with an anti-CD34 antibody functionalized heparin-collagen multilayer.

The in-stent restenosis (ISR) and the late stent thrombosis (LAST) represent the most common failures of stent implantation and are both mediated at the injured endothelium. The natural endothelium healing mechanism provides an approach to achieve in situ endothelialization of the implant by stimulating the neighboring endothelial cells (ECs) migration or capturing the circulating endothelial cells (CEC) directly from the blood circulation. An anti-CD34 antibody functionalized multilayer of heparin/collagen is developed here via layer-by-layer assemble. The ellipsometry and QCM-D results demonstrate that the multilayer coatings with slight glutaraldehyde cross-linking are stable in static incubation and flushing conditions, respectively. The in vitro hemocompatibility tests and cell culture results indicate that both heparin/collagen multilayers with or without the anti-CD34 antibody functionalization not only preserve good hemocompatibility, but also promote cell attachment and growth notably. While the heparin/collagen multilayer coatings show no selectivity in promotion of ECs and smooth muscle cells (SMCs), the anti-CD34 antibody functionalized heparin/collagen multilayers can specifically promote the attachment and growth of the vascular ECs. The metabolic activity assessment and the NO secretion measurements further indicate that the adherent ECs on the anti-CD34 antibody functionalized heparin/collagen multilayer surface have better viability and possess the specific function of the natural vascular ECs. In vivo experiments indicate that the anti-CD34 antibody can enrich and accelerate the attachment of the vascular cells onto the stent and rapid endothelialization is realized. While no significant difference of neointimal hyperplasia is observed between the bare metal stents and heparin/collagen multilayer modified stents, the neointimal hyperplasia on the anti-CD34 antibody functionalized multilayer modified stents is significantly inhibited. The success of the anti-CD34 antibody functionalized heparin/collagen multilayer coating in rapid endothelialization and anti-restenosis might indicate that the immobilization of ECs specific ligand onto a cytocompatible matrix can be a good approach for in situ endothelialization and a possible solution to ISR.

Senescent endothelial progenitor cells from dogs with pulmonary arterial hypertension: a before-after self-controlled study.

Previous studies have underlined the importance of endothelial dysfunction and microvascular occlusion in the pathogenesis of pulmonary artery hypertension (PAH). Since the endothelial progenitor cells (EPCs) are involved in maintaining endothelial homeostasis, we observed the change of peripheral EPCs in canines before and after PAH onset. PAH was induced by intra-pulmonary artery injection of dehydromonocrotaline (DHMC) in nine beagles. Before and 48 h and 6 weeks after DHMC injection, 40 ml peripheral blood was obtained from the femoral vein. Circulating EPCs were identified as CD133 + KDR + cells and numerated by fluorescence-activated cell sorter; the EPCs functional capacity was determined by in vitro tubule-forming assay. The senescence of EPCs was determined by beta-galactosidase staining. At each time point, 2 ml blood from femoral artery was obtained for arterial oxygen pressure (PaO(2)). Forty-eight hours after DHMC injection, treated beagles suffered from hypoxemia; however, both the number and the tubule-forming capacity of EPCs were transiently raised. Six weeks later, PAH was confirmed by obviously high mean pulmonary arterial pressure (20.2 +/- 1.64 vs. 11.3 +/- 2.0 mmHg, p < 0.05) and low PaO(2) (69.30 +/- 9.15 vs. 95.94 +/- 1.43 mmHg, p < 0.01) in beagles after DHMC treatment, and their EPCs exhibited a predominant decrease in either the number (206.1 +/- 26.8 vs. 632.8 +/- 42.8 cells/ml blood, p < 0.01) or the tubule-forming capacity (21.1 +/- 2.8 vs. 11.2 +/- 2.8 tubules/x200 field, p < 0.01). Additionally, senescence-associated beta-galactosidase-positive EPCs were significantly increased. Our data suggested that, after the acute stage of DHMC injury to pulmonary vessels, the EPCs from PAH beagles suffered from exhaustion and senescence.