Comprehensive transcriptomics and metabolomics analyses reveal that hyperhomocysteinemia is a high risk factor for coronary artery disease in a chinese obese population aged 40-65: a prospective cross-sectional study.

BACKGROUND: Clinical observations suggest a complex relationship between obesity and coronary artery disease (CAD). This study aimed to characterize the intermediate metabolism phenotypes among obese patients with CAD and without CAD. METHODS: Sixty-two participants who consecutively underwent coronary angiography were enrolled in the discovery cohort. Transcriptional and untargeted metabolomics analyses were carried out to screen for key molecular changes between obese patients with CAD (CAD obese), without CAD (Non-CAD obese), and Non-CAD leans. A targeted GC-MS metabolomics approach was used to further identify differentially expressed metabolites in the validation cohorts. Regression and receiver operator curve analysis were performed to validate the risk model. RESULTS: We found common aberrantly expressed pathways both at the transcriptional and metabolomics levels. These pathways included cysteine and methionine metabolism and arginine and proline metabolism. Untargeted metabolomics revealed that S-adenosylhomocysteine (SAH), 3-hydroxybenzoic acid, 2-hydroxyhippuric acid, nicotinuric acid, and 2-arachidonoyl glycerol were significantly elevated in the CAD obese group compared to the other two groups. In the validation study, targeted cysteine and methionine metabolomics analyses showed that homocysteine (Hcy), SAH, and choline were significantly increased in the CAD obese group compared with the Non-CAD obese group, while betaine, 5-methylpropanedioic acid, S-adenosylmethionine, 4-PA, and vitamin B2 (VB2) showed no significant differences. Multivariate analyses showed that Hcy was an independent predictor of obesity with CAD (hazard ratio 1.7; 95%CI 1.2-2.6). The area under the curve based on the Hcy metabolomic (HCY-Mtb) index was 0.819, and up to 0.877 for the HCY-Mtb.index plus clinical variables. CONCLUSION: This is the first study to propose that obesity with hyperhomocysteinemia is a useful intermediate metabolism phenotype that could be used to identify obese patients at high risk for developing CAD.

Myocyte Enhancer Factor 2A Plays a Central Role in the Regulatory Networks of Cellular Physiopathology.

Cell regulatory networks are the determinants of cellular homeostasis. Any alteration to these networks results in the disturbance of cellular homeostasis and induces cells towards different fates. Myocyte enhancer factor 2A (MEF2A) is one of four members of the MEF2 family of transcription factors (MEF2A-D). MEF2A is highly expressed in all tissues and is involved in many cell regulatory networks including growth, differentiation, survival and death. It is also necessary for heart development, myogenesis, neuronal development and differentiation. In addition, many other important functions of MEF2A have been reported. Recent studies have shown that MEF2A can regulate different, and sometimes even mutually exclusive cellular events. How MEF2A regulates opposing cellular life processes is an interesting topic and worthy of further exploration. Here, we reviewed almost all MEF2A research papers published in English and summarized them into three main sections: 1) the association of genetic variants in MEF2A with cardiovascular disease, 2) the physiopathological functions of MEF2A, and 3) the regulation of MEF2A activity and its regulatory targets. In summary, multiple regulatory patterns for MEF2A activity and a variety of co-factors cause its transcriptional activity to switch to different target genes, thereby regulating opposing cell life processes. The association of MEF2A with numerous signaling molecules establishes a central role for MEF2A in the regulatory network of cellular physiopathology.

MEF2A Is the Trigger of Resveratrol Exerting Protection on Vascular Endothelial Cell.

Both resveratrol and myocyte enhancer factor 2A (MEF2A) may protect vascular endothelial cell (VEC) through activating the expression of SIRT1. However, the relationship between resveratrol and MEF2A is unclear. We aimed to investigate the deeper mechanism of resveratrol in protecting vascular endothelial cells and whether MEF2A plays a key role in the protective function of resveratrol. Human umbilical vein endothelial cell (HUVEC) was used for in vitro study, and small interfere RNA was used for silencing MEF2A. Silencing MEF2A in the vascular endothelium (VE) of ApoE-/- mice was performed by tail injection with adeno associated virus expressing si-mef2a-shRNA. The results showed that treatment of HUVEC with resveratrol significantly up-regulated MEF2A, and prevented H2O2-induced but not siRNA-induced down-regulation of MEF2A. Under various experimental conditions, the expression of SIRT1 changed with the level of MEF2A. Resveratrol could rescue from cell apoptosis, reduction of cell proliferation and viability induced by H2O2, but could not prevent against that caused by silencing MEF2A with siRNA. Silencing MEF2A in VE of apoE-/- mice decreased the expression of SIRT1, increased the plasma LDL-c, and abrogated the function of resveratrol on reducing triglyceride. Impaired integrity of VE and aggravated atherosclerotic lesion were observed in MEF2A silenced mice through immunofluorescence and oil red O staining, respectively. In conclusion, resveratrol enhances MEF2A expression, and the upregulation of MEF2A is required for the endothelial protective benefits of resveratrol in vitro via activating SIRT1. Our work has also explored the in vivo relevance of this signaling pathway in experimental models of atherosclerosis and lipid dysregulation, setting the stage for more comprehensive phenotyping in vivo and further defining the molecular mechanisms.

Inhibition of platelet activation and aggregation by furostanol saponins isolated from the bulbs of Allium macrostemon Bunge.

Three new furostanol saponins (FSs) were recently isolated from the dried bulbs of Allium macrostemon and were shown to have antiplatelet effects. This study investigated the inhibitory capabilities of these compounds on adenosine diphosphate (ADP)-induced human platelet activation. FS-1, when compared with the other 2, had a potent inhibitory effect on ADP-induced platelet aggregation and on the expression of P-selectin and integrin ß-3. FS-1 also inhibited Ca mobilization and significantly decreased phosphorylated AKT expression in ADP-activated platelets. The suppression by FS-1 of ADP-induced platelet activation and aggregation shown in this study indicate its potential for therapeutic applications.

[Role of sphingosine 1-phosphate receptor signaling in hematopoietic stem/progenitor cell transmigration].

OBJECTIVE: To determine the role of sphingosine 1-phosphate receptor (S1PRs ) signaling in CD34+ hematopoietic stem/progenitor cell transmigration. METHODS: CD34(+) cells were separated by Ficoll density gradient centrifugation and incubated in DMEM medium with 10% fetal calf serum. The cells were pretreated by FTY720, with or without pertussis toxin (PTX) and antiCXCR4 mAb in the medium, followed by addition of 100 ng/ml SDF-1 into the lower chamber of a Costar 24-well transwell. The migrated cells were counted using FACS and the migrating rates were determined. The expressions of sphingosine 1-phosphate receptors were analyzed in CD34(+) cells before and after the transmigration by reverse transcriptase- polymerase chain reaction (RT-PCR). Cord blood CD34(+) cells were treated with or without FTY720 (10(+) mol/L), and the expressions of CD49d (VLA-4), CD11a (LFA-1), and CD62L (L-selectin) were analyzed at 1, 8, and 16 h after the treatment. RESULTS: While FTY720 did not affect spontaneous migration, a substantial increase of SDF-1-induced transmigration was observed in the presence of FTY720 (15.26 2.14 to 28.64 2.37). The FTY720-enhanced transmigration was completely blocked by addition of PTX or antiCXCR4 mAb. S1p1-5 was expressed in fresh isolated cord blood CD34(+) cells. The migrating cells stimulated by FTY720 and SDF-1 only expressed S1P1, S1P3, and S1P4. The expressions of CD49d, CD11a and CD62L on CD34(+) cells treated with FTY720 remained unchanged at the selected time points as compared with the control. CONCLUSIONS: S1PRs are involved the transmigration of CD34(+) cells. The activation of S1PRs results in increased chemotactic response of CD34(+) to SDF-1. These effects are mediated through CXCR4 and PTX-sensitive Gi proteins. Only the CD34(+) cells expressing the specific receptors can rapidly transmigrate. The activation of the S1PRs does not affect the expressions of the adhesion molecules on cord blood CD34(+) cells.

[Targeted adhesion of platelet receptor-specific microbubble agent to thrombus in vitro].

OBJECTIVE: To examine the thrombus-targeting effect of platelet receptor-specific lipid microbubbles. METHODS: The targeted microbubbles were prepared by coupling Arg-Gly-Asp-Ser (RGDS) with the lipid microbubbles, which were added to the microthrombus generated by platelet aggregation. The effects of the targeted microbubbles on the ultrasonic signal was observed in an artificial thrombus model. RESULTS: The targeted microbubbles were adhesive to the microthrombus, while the non-targeted microbubbles did not possess this property. The ultrasonic signal of the thrombus border was enhanced significantly after the addition of the targeted microbubbles. CONCLUSIONS: Platelet receptor-specific microbubbles possess significant adhesive property to the thrombus and can improve signal-to-noise ratio of the thrombus, suggesting the potential value of the targeted microbubbles for clinical application in the diagnosis and treatment of thrombus.

[Establishment of a modified canine model of acute cardiac insufficiency].

OBJECTIVE: To establish a canine model of acute cardiac insufficiency (ACI) by coronary artery occlusion and right ventricular pacing. METHODS: Twelve dogs were subjected to rapid ventricular pacing after ligation of the left anterior descending coronary artery (LAD), to induce the cardiac output (CO) to reduce by 25%; and 50%; from the basal level. The arterial pressure (AP), arterial oxygen saturation (SaO(2)), mean right atrial pressure (mRAP), mean pulmonary capillary wedge pressure (mPCWP), and systemic vascular resistance (SVR) were measured in the dogs according to different CO conditions. Echocardiography was used to measure the cardiac size and left ventricular ejection fraction (LVEF). RESULTS: CO was decreased by 25%; and 50%; steadily from the basal level after right ventricular pacing following ligation of the LAD. AP and SaO(2) decreased while mRAP, mPCWP, and SVR increased significantly following CO reduction. The cardiac cavity became larger while LVEF decreased after CO was decreased by 25% and 50%. CONCLUSION: Canine model of ACI can be successfully established by right ventricular pacing following ligation of the LAD.

[Ultrasound microbubbles promote thrombolysis of rabbit femoral artery thrombus].

OBJECTIVE: To evaluate the efficacy of intravenous ultrasound microbubbles for thrombolysis of arterial thrombus without using thrombolytic drugs. METHODS: Twelve rabbit models of acute bilateral femoral artery thrombosis were established and 6 of them received transcutaneous ultrasound and intravenous albumin microbubble treatment for thrombosis on one side while only microbubble treatment for the other side. The other 6 rabbits received ultrasound treatment on one side but no treatment on the other to serve as the control group. RESULTS: None of the 6 arteries treated with microbubbles alone and only 2 arteries treated with ultrasound alone in the 6 control rabbits were recanalized. All the 6 femoral arteries treated with microbubbles together with ultrasound were recanalized (P=0.014), with significantly shorter patent time and smaller residual thrombus cross-sectional area than those of the arteries with only ultrasound treatment (P=0.004 and P=0.003, respectively). CONCLUSION: Treatment with intravenous microbubbles assisted by transcutaneous ultrasound effectively promotes arterial thrombolysis in vivo, and this technique can be of significance in clinical treatment of acute thrombotic occlusions.

[Conditions of contrast ultrasound that affect the proliferation of rat smooth muscle cells].

OBJECTIVE: To investigate the effect of an echo-contrast agent on the proliferation of rat smooth muscle cells under different ultrasound conditions. METHODS: The vascular smooth muscle cells of rats were cultured with echo-contrast agent in 96-well plates, followed by exposure to ultrasound of different conditions. Trypan blue staining was performed 48 h later, and the proliferation of the cells observed by MTT assay. RESULTS: No cytotoxicity was found by trypan blue staining when the mechanical index of ultrasound was below 0.75. Compared with the control cells, the proliferation of the smooth muscle cells was decreased following the exposure as the mechanical index of ultrasound increased. The most obvious inhibition of cell proliferation was resulted when the microbubble concentration was 20% for a 60-second exposure. CONCLUSIONS: The inhibition of the vascular smooth muscle cell proliferation by echo-contrast agent destruction is correlated with the mechanical index of the ultrasound, concentration of the echo-contrast agent, and exposure time of ultrasound.

[Effect of echo-contrast agent on rat vascular smooth muscle cell proliferation during ultrasound exposure].

OBJECTIVE: To investigate the effect of echo-contrast agent on rat vascular smooth muscle cell (VSMC) proliferation in the presence of ultrasound exposure. METHODS: The VSMCs of rats were cultured in 6-well plates with or without the echo-contrast agent and stained with trypan blue at 3, 24, and 48 h respectively after ultrasound exposure for 1 min at 2 MHz, 0.25 mechanical index (MI). At each time point as indicated after the exposure, the cells in parallel wells were trypsinized for cell counting using Coulter counter. RESULTS: No cytotoxicity was found in trypan blue staining. Compared with the control cells, the proliferation of VSMCs was inhibited by echo-contrast agent and adjunctive ultrasound within 24 h, but another 24 h later, the effect failed to be observed. CONCLUSIONS: The proliferation of VSMC was inhibited by with low mechanical index cavitation activity of contrast agents.

[Role of platelet membrane glycoprotein II b/III a receptor activation in no-reflow after myocardial reperfusion].

OBJECTIVE: To observe the changes in the activity of platelet glycoprotein (GP) IIb/IIIa receptor following the occurrence of no-reflow after myocardial reperfusion, to explore the measures for clinical management of this condition. METHODS: Nine canine models of no-reflow following myocardial ischemia verified by reperfusion myocardial contrast echocardiography were used in this investigation. The peripheral venous blood (PVB) and sinus venous blood (SVB) were sampled before myocardial reperfusion (after a 3-hour myocardial ischemia) and after a 3-hour reperfusion for determinating GP IIb/IIIa receptor activities by means of enzyme-linked immunosorbent assay (ELISA). RESULTS: The activity of platelet GP IIb/IIIa of PVB, either in 3-hour ischemic group or in 3-hour reperfusion group, was elevated significantly (P < 0.001), suggesting platelet activation. Elevated platelet GP IIb/IIIa receptor activity in SVB occurred only in 3-hour ischemic group, and the 3-hour reperfusion group (P < 0.001) and the no-reflow group had significantly decreased activities, which was more obvious in the latter group (P < 0.01). The findings signified the consumption of the platelet GP IIb/IIIa receptors in the myocardial microcirculation and the presence of platelet aggregation. CONCLUSIONS: Myocardial ischemia may activate the platelets to express GP IIb/IIIa receptors through stress response mechanism and damage the endothelia of the microvasculature to incur adhesion and aggregation of the platelets within the microcirculation, which may be one of the pathogeneses for myocardial no-reflow phenomenon.

Value of echocardiography for observing left ventricular hypertrophy in the diagnosis of myocardial microvascular damage in hypertensives.

OBJECTIVE: To investigate the value of the echocardiographic observation of the left ventricular hypertrophy (LVH) in diagnosing myocardial microvascular damage in patients with essential hypertension (EH). METHODS: After intravenous injection with Quanfuxian (a contrast agent consisting of albumin and C3F8 prepared by Nanfang Hospital), the values of A (the maximum number of microbubbles accumulating in the local tissues for assessing the density of local microvessels), beta (the filling velocity of contrast agent for evaluating local blood flow velocity) and A x beta (the product of A and beta for estimating local myocardial blood flow) at rest and after dipyridamole injection were measured by intermittent harmonic imaging with myocardial contrast echocardiography (MCE). The ratios of A and beta along with the microvascular coronary flow velocity reserve (CFVR) were also calculated. RESULTS: Compared with the control group, the rest values of A, beta and A.beta in EH patients were higher, especially in those with LVH. After dipyridamole injection, the values of A, beta, A x beta and the ratios of A and beta, along with CFVR as well, were significantly lowered (P <0.01), and the reductions were especially obvious in LVH cases. As the hypertension exacerbated, the values of A and A x beta tended to increase in positive correlation with systolic and diastolic blood pressure (P <0.01), while the ratio of A and CFVR were decreased, the latter was inversely correlated with diastolic blood pressure (r=-0.55, P <0.01). Positive correlations were noted of the values of A and A x beta with the left ventricular mass and left ventricular mass index (P <0.01). CONCLUSION: EH patients, especially those with LVH, are characterized by increased rest myocardial microvascular blood flow, impaired myocardial microvascular flow reserve and endothelium independent vasodilation relaxing ability, and reduced capillary density, and these conditions tend exacerbate as the disease worsens. Microvascular function impairment should be suspected when complication of LVH arises in the EH patients. As a new important noninvasive technique, MCE can be a promising modality for diagnosing microvascular disease in essential hypertension.

[Discrepancy between the blood flow in hyperperfused epicardial coronary vessels and myocardial microcirculation following reperfusion: a study in canines].

OBJECTIVE: To investigate the hemodynamic changes in the epicardial coronary blood flow (ECBF) and myocardial microcirculation (MMC) during reactive hyperemia (RH) in response to reperfusion following 2-min ischemia in the left anterior descending coronary artery of canines. METHODS: Twelve adult mongrel dogs were used, whose left anterior descending coronary artery was separated and ligated for 2 min twice below the first branch. The heart rate, systolic blood pressure, diastolic blood pressure, mean blood pressure, ECBF and MMC were measured respectively before and after the ligation and at 5, 10, 15, 30, 45, 60, 90 and 120 s after reperfusion. ECBF was determined with Doppler coronary flowmeter and MMC derived from the ultrasonic intensity measured by myocardial contrast echocardiography. RESULTS: During the course of RH, ECBF and MMC both evinced responses to hyperperfusion but in manners different in view of their hemodynamic changes, demonstrating the mismatch between them in this condition. ECBF exhibited a much higher peak flow increase than MMC. CONCLUSIONS: RH occurs in response to reperfusion after short-term (2 min) myocardial ischemia, when the discrepancy arises between ECBF and MMC. The primary mechanism might involve the recruitment of the capillaries and the opening of the shunt through the capillaries, and as a consequence, the myocardial perfusion is increased at the cost of decreased reserve of the coronary microcirculation.