Zhang Fr

Resveratrol reduces endothelial progenitor cells senescence through augmentation of telomerase activity by Akt-dependent mechanisms

Recent studies have shown that resveratrol increased endothelial progenitor cells (EPCs) numbers and functional activity. However, the mechanisms remain to be determined. Previous studies have demonstrated that increased EPC numbers and activity were associated with the inhibition of EPC senescence, which involves activation of telomerase. Therefore, we investigated whether resveratrol inhibits the onset of EPC senescence through telomerase activation, leading to potentiation of cellular activity.

Endothelial progenitor cells may inhibit apoptosis of pulmonary microvascular endothelial cells: new insights into cell therapy for pulmonary arterial hypertension

BACKGROUND AIMS Endothelial apoptosis underlies the pathophysiology of pulmonary arterial hypertension (PAH). Some factors/cytokines released by endothelial progenitor cells (EPC) have been revealed as potent inhibitors of apoptosis. The aim of this study was to investigate the effects of EPC on pulmonary microvascular endothelial cell (PMVEC) survival with the PAH condition. METHODS PMVEC apoptosis was induced by high shear stress (HSS) with serum starvation or pro-inflammatory factors in an artificial capillary system. EPC were delivered into monocrotaline-induced PAH nude rats. RESULTS PMVEC apoptosis under HSS and serum starvation conditions was significantly inhibited by EPC conditioned medium (CM). It was attenuated by vascular endothelial growth factor (VEGF)-A or -B blocking. EPC CM promoted PMVEC proliferation, which was weakened by VEGF-A or interleukin (IL)-8 blocking. The EPC CM caused less apoptosis of PMVEC induced by HSS plus pro-inflammatory factors. The anti-apoptotic effect of EPC CM was attenuated by blockade of either vascular endothelial growth factor receptor (VEGFR)-1 or -2. However, the pro-proliferating effect appeared to be weakened only by VEGFR-2 blocking. Both Erk1/2 and Akt phosphorylation were enhanced by EPC CM. VEGFR-2 blockage led to significant inhibition of Erk1/2 and Akt activation; VEGFR-1 blockage only of Erk1/2 activation. Human-origin VEGF co-localized with incorporated EPC in small pulmonary arterioles, and EPC transplantation resulted in down-regulation of caspase-3 expression. CONCLUSIONS The VEGF-A/B-VEGFR-1/2-Erk1/2 signal pathway took major responsibility for the anti-apoptotic effects of EPC on PMVEC, and VEGF-A-VEGFR-2-Akt for pro-proliferating effects. Growth factors, secreted in a paracrine manner by transplanted EPC, inhibited cell apoptosis in PAH lung.

Captopril administered at night restores the diurnal blood pessure rhythm in adequately controlled, nondipping hypertensives

The aim of our study was to evaluate whether captopril administered at night, can shift the circadian blood pressure (BP) from a nondipper to a dipper pattern in adequately controlled hypertensive patients, who continued their antihypertensive therapy. In a prospective, randomized, double blind, placebo-controlled designed study, we enrolled 121 treated, adequately controlled nondipping hypertensive patients. All patients were randomly assigned to 12.5 mg captopril or placebo treatment administered at night. In case of nondippers, the dosage of captopril or placebo was doubled after two weeks of treatment, while for dippers antihypertensive regimens were not changed. After another two weeks, all patients underwent ambulatory BP monitoring. Our results show that at the end of the active treatment period, the prevalence of a dipping diurnal BP pattern in the captopril group (70%) was significantly higher than that in the placebo group (9.8%, P < 0.001). Nighttime BP, night/day BP ratio, nighttime BP load and 24-h systolic BP were significantly lower after 4 weeks nighttime captopril treatment compared to baseline. In conclusion, the present study demonstrates for the first time that captopril administered at night can restore the diurnal BP rhythm and decrease the elevated night/day BP ratio in appropriately controlled, nondipper hypertensive patients. These results were mainly due to the decrease of nighttime BP.

Proteomic analysis of the serum in patients with idiopathic pulmonary arterial hypertension.

Idiopathic pulmonary arterial hypertension (IPAH) is a rare disease of unknown etiology. The exact pathogenesis of pulmonary arterial hypertension is still not well known. In the past decades, many protein molecules have been found to be involved in the development of IPAH. With proteomic techniques, profiling of human plasma proteome becomes more feasible in searching for disease-related markers. In present study, we showed the protein expression profiles of the serum of IPAH and healthy controls after depleting a few high-abundant proteins in serum. Thirteen spots had changed significantly in IPAH compared with healthy controls and were identified by LC-MS/MS. Alpha-1-antitrypsin and vitronectin were down-regulated in IPAH and may be valuable candidates for further explorations of their roles in the development of IPAH.

Puerarin reduces endothelial progenitor cells senescence through augmentation of telomerase activity

Endothelial progenitor cells (EPCs) play an important role in both reendothelialization and neovascularization. Ex vivo expansion of EPCs might be useful for potential clinical cell therapy of ischemic diseases. However, ex vivo cultivation of EPCs leads to rapid onset of EPCs senescence, thereby severely limiting the proliferative capacity and clonal expansion potential. Therefore, we investigated whether puerarin might be able to prevent senescence of EPCs. EPCs were isolated from peripheral blood and characterized. After ex vivo cultivation, EPCs became senescent as determined by acidic beta-galactosidase staining. Puerarin dose dependently prevented the onset of EPCs senescence in culture. Moreover, puerarin increased proliferation of EPCs as assessed by BrdU incorporation assay and colony-forming capacity. To get further insights into the underlying mechanisms of these effects induced by puerarin, we measured telomerase activity and determined the phosphorylation of serine/threonine protein kinase Akt by using western blot. Puerarin significantly increased telomerase activity and phosphorylation of Akt, a downstream effector of phosphoinositide 3-kinase (PI-3K). Moreover, pretreatment with PI-3K blockers, either wortmannin or LY294002, significantly attenuated the puerarin puerarin-induced telomerase activity. Taken together, the results of the present study indicated that puerarin delayed the onset of EPCs senescence, which may be related to the activation of telomerase through the PI-3K/Akt pathway. The inhibition of EPCs senescence by puerarin in vitro may improve the functional activity of EPCs in a way that is important for potential cell therapy.

Study of the correlation between blood lipid levels and the severity of coronary atherosclerosis in a Chinese population sample.

Objective — To investigate the relationship between blood lipid levels with severity of coronary artery atherosclerosis in a Chinese population sample. Methods and results — According to coronary angiography results, 363patients (287men and 76women) with coronary artery atherosclerosis were divided into four groups: the single-vessel group (I, n=125), the double-vessel group (II, n=113), the triple-vessel group (III, n=107) and the multivessel group (IV, n=18).The severity of coronary artery atherosclerosis was quantified with a modified Gensini score on the basis of angiographic imaging. Serum triglycerides (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), non-high density lipoprotein cholesterol (non-HDL-C) were measured before angiography in all groups. Levels of serum TC, LDL-C and non-HDL-C of the II, III and IV group were significantly higher than those of the I group (4.78 ± 0.82mmol/L and 4.87 ± 1.50mmol/L and 4.73 ± 0.99mmol/L vs. 4.38 ± 0.93mmol/L, 2.91 ± 0.68mmol/L and 2.74 ± 1.23mmol/L and 2.64 ± 0.84mmol/L vs. 2.30 ± 0.77mmol/L, 3.58 ± 0.75mmol/L and 3.59 ± 1.41mmol/L and 3.43 ± 0.94mmol/L vs. 3.17 ± 0.91mmol/L; p < 0.05); the mean levels of TC, LDL-C and non-HDL-C associated positively with the Gensini score. Conclusion — Serum lipid levels correlate positively with the severity of coronary artery atherosclerosis in a Chinese population sample. Patients with higher levels of serum TC, LDL-C and non-HDL-C have more severe coronary atherosclerosis, compared with those with low levels of serum TC, LDL-C and non-HDL-C.

Cariporide attenuates myocardial ischaemia, reperfusion injury and apoptosis in isolated rat hearts.

Objective — Inhibition of Na+/H+ exchanger (NHE) may protect the ischaemic reperfused myocardium by attenuating sodium overload. This study investigated the time-dependent beneficial effect of the NHE1 inhibitor cariporide and the effect on early apoptosis in a rat model of ischaemia and reperfusion. Methods and results — The hearts of rats were perfused in a Langendorff apparatus. In the first part of the experiment, rats were divided into four groups: I/R (cariporide was not given), HOEPr+I/R (cariporide was given 15min before ischaemia), HOE-Is+I/R (cariporide was given shortly before ischaemia), HOE-Re+I/R (cariporide was given during reperfusion). The left ventricular systolic pressure (LVSP), the left ventricular end-diastolic pressure (LVEDP), arrhythmia, coronary flow and myocardial enzymes were measured. In the second part of the experiment, hearts were bathed in the presence or absence of cariporide before ischaemia. Terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labelling (TUNEL) assays were used to quantify apoptotic cells. Improvement of recovery from ischaemia, defined as increased LVSP, decreased LVEDP, improvement in arrhythmia score, CK-MB and LDH was more significant in the HOE-Pr+I/R group than in the I/R group. Furthermore, cariporide given during ischaemia caused intermediate improvement of ischaemic recovery, while there was no difference between HOE-Re+I/R and I/R hearts. The number of apoptotic cells after ischaemia and reperfusion was 51.8±15.2 per 1000 cardiomyocytes compared to 11.5±5.7 (p < 0.05) in hearts pretreated before ischaemia with cariporide. Conclusions — In conclusion, cariporide decreases the degree of impaired cardiac recovery and early apoptosis after ischaemia/reperfusion injury.The cardioprotective effects of cariporide are more pronounced when the drug is given before ischaemia.

Effects of diltiazem on platelet activation and cytosolic calcium during percutaneous transluminal coronary angioplasty

Aims: To evaluate effects of diltiazem on platelet hyper-reactivity in situations associated with endothelial injury and their possible relationship to cytosolic calcium concentration. Methods: Blood samples were collected at seven time points from 35 patients undergoing percutaneous transluminal coronary angioplasty (PTCA) who received combined diltiazem and aspirin/ticlopidine therapy or aspirin/ticlopidine therapy alone. Platelet expression of glycoprotein IIb/IIIa and P-selectin, production of thromboxane B2, and cytosolic calcium concentration were measured, respectively, by whole blood flow cytometry, radioimmunoassay, and fluorospectrophotometry. The effects of diltiazem of different concentrations on expression of glycoprotein IIb/IIIa and P-selectin were also studied in vitro in blood samples from patients with chronic stable angina. Results: Of the two treatments, aspirin/ticlopidine therapy did not prevent an acute increase of expression of glycoprotein IIb/IIIa and P-selectin and plasma thromboxane B2 five minutes and 10 minutes after first inflation and 10 minutes after PTCA, whereas combined diltiazem and aspirin/ticlopidine therapy had a significant inhibitory effect. In the group receiving aspirin/ticlopidine therapy, there was a short term increase of platelet [Ca2+]i immediately after PTCA which was significantly reduced by diltiazem treatment. Expression of glycoprotein IIb/IIIa and P-selectin was significantly inhibited in vitro by diltiazem in the concentration of 200 ng/ml or higher, but not 50 ng/ml. Conclusions: Combined diltiazem and aspirin/ticlopidine therapy significantly inhibited platelet activation that continued in the presence of conventional aspirin/ticlopidine treatment. Antiplatelet effects of diltiazem were probably a consequence of reduction of platelet [Ca2+]i and may only be achieved in higher than therapeutic concentrations.

Estrogen receptor α gene PvuII polymorphism and coronary artery disease: a meta-analysis of 21 studies

The association between the estrogen receptor α gene (ESR1) PvuII polymorphism (c.454-397T>C) and coronary artery disease (CAD) is controversial. Thus, we conducted a meta-analysis to evaluate the relationship. Data were collected from 21 studies encompassing 9926 CAD patients and 16710 controls. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the relationship between PvuII polymorphism and CAD. The polymorphism in control populations in all studies followed Hardy-Weinberg equilibrium. We found a significant association between ESR1PvuII polymorphism and CAD risk in all subjects. When the data were stratified by region, a significant association between ESR1PvuII polymorphism and CAD risk was observed in Asian populations but not in Western populations. The current study suggests that ESR1PvuII polymorphism has an important role in CAD susceptibility.

EFFECT OF HEPARIN ON ACTIVATION OF PLATELET FUNCTION IN PATIENTS DURING RADIOFREQUENCY CATHETER ABLATION

1 Thromboembolism occurs in 0.4–2.0% of patients undergoing radiofrequency catheter ablation (RFCA). Some studies have shown that treatment with heparin inhibits the activation of coagulation and fibrinolysis. No study has directly measured the activation of platelet aggregation to investigate the effect of heparin on platelet function. The purpose of the present study was to observe the inhibitory effect of heparin on platelet activity in patients undergoing RFCA. 2 Sixty‐two patients with supraventricular tachycardia were observed and divided into a heparin‐treatment group and a control group. Changes in platelet aggregability (PAG) and thromboxane B2 (TXB2) in the blood samples of all patients at different times (before, after electrophysiological study, immediately after and 10 and 30 min after the RFCA procedure) were observed. 3 No indication of clinically symptomatic thromboembolism and no major differences in baseline characteristics and procedure were apparent in either group. The levels of PAG and TXB2 were all clearly increased after the electrophysiological study (all P < 0.05). Immediately after RFCA, PAG and TXB2 levels were significantly increased in both groups and remained elevated 30 min after the procedure (all P < 0.05). In the heparin‐treatment group, the increases in PAG (54.69 3.24%) and TXB2 (29.01 1.84%) caused by RFCA were lower than changes observed in the control group (70.92 3.45 and 44.70 3.28%, respectively; both P < 0.01). Moreover, treatment with heparin normalized the elevated level of PAG 30 min after RFCA more clearly. 4 The results of the present study suggest that intravenous heparin treatment during the operation inhibits the activation of platelets induced by RFCA.