Search

Exosome secretion is an important paracrine way of endothelial progenitor cells (EPCs) to modulate resident endothelial cells. The osteocalcin (OCN)-expressing EPCs have been found to be increased in cardiovascular disease patients and are considered to be involved in the process of coronary atherosclerosis. Since OCN has been proven to prevent endothelial dysfunction, this study aimed to evaluate the effect of exosomes derived from OCN-overexpressed EPCs on endothelial cells. Exosomes derived from EPCs (Exos) and OCN-overexpressed EPCs (OCN-Exos) were isolated and incubated with rat aorta endothelial cells (RAOECs) with or without the inhibition of OCN receptor G protein-coupled receptor family C group 6 member A (GPRC6A). The effects of exosomes on the proliferation activity of endothelial cells were evaluated by CCK-8 assay, and the migration of endothelial cells was detected by wound healing assay. A tube formation assay was used to test the influence of exosomes on the angiogenesis performance of endothelial cells. Here, we presented that OCN was packed into Exos and was able to be transferred to the RAOECs via exosome incorporation, which was increased in OCN-Exos groups. Compared with Exos, OCN-Exos had better efficiency in promoting RAOEC proliferation and migration and tube formation. The promoting effects were impeded after the inhibition of GPRC6A expression in RAOECs. These data suggest that exosomes from OCN-overexpressed EPCs have a beneficial regulating effect on endothelial cells, which involved enhanced OCN-GPRC6A signaling.

Objective: To examine the impact of mild hypothermia on cardiac function, myocardial tissue integrity, and 48 hours mortality in a rabbits model of ventricular fibrillation after restoration of spontaneous circulation (ROSC)., Methods: The rabbits were randomly divided into four groups: normothermic post ROSC (NTPR, n = 10), mild hypothermia post ROSC (HTPR, n = 10), normothermic control (NTC, n = 8) and mild hypothermia control (HTC, n = 8). Ventricular fibrillation was induced by trans-epicardium electric-shook with alternating current in all the animals and ROSC was achieved through administration of adrenaline (i.v.) and artificial ventilation in group NTPR and HTPR. The body temperature of the animals was kept either at (39.0 ± 0.5) centigrade (NTPR and NTC) or (33.5 ± 0.5) centigrade (HTPR and HTC) for 4 hours after surgery for hemodynamic index data collection 0.5, 1, 2, 3 and 4 hours after surgery, 48 hours later, the mortality in the animals was recorded, and myocardial tissue samples were collected from survived animals for morphological examination by light and electric microscopy and analysis of apoptosis by terminal-deoxynucleotidyl transferase mediated nick end labeling (TUNEL) staining. The content of ATP, ADP and AMP in the tissue samples was measured by high performance liquid chromatography (HPLC) for the calculation of energy charges (EC)., Results: (1)Hemodynamic indexes: as compared to the NTC group, HTC group exhibited significantly lower levels of heart rate (HR) and -dp/dt max in all the time points. No significant difference between the two groups in the levels of +dp/dt max and mean artery pressure (MAP) was found in all the time points but 0.5 hour. There was no significant difference in the levels of left ventricular end-diastolic pressure (LVEDP), left ventricular end-systolic pressure (LVESP), and femoral artery blood pressure between the two groups.(2) In comparison with NTPR group, HTPR group exhibited significantly (all P < 0.05) lower levels of HR (bpm) and -dp/dt max in all time points (ROSC 0.5, 1, 2, 3, 4 hours: HR 216.5 ± 33.3 vs. 292.9 ± 38.4, 218.2 ± 28.0 vs. 294.3 ± 37.0, 227.5 ± 25.4 vs. 291.4 ± 25.3, 232.4 ± 27.4 vs. 278.1 ± 30.8, 230.6 ± 22.0 vs. 285.1 ± 38.2; -dp/dt max 1847.1 ± 241.2 vs. 2383.3 ± 470.9, 1860.7 ± 167.8 vs. 2154.6 ± 319.5, 1822.3 ± 389.7 vs. 2239.7 ± 379.0, 1950.6 ± 412.9 vs. 2229.6 ± 392.4, 1875.7 ± 555.6 vs. 2396.7 ± 420.1). There was no significant difference between the two groups in the levels of LVEDP, +dp/dt max, LVESP, and femoral artery blood pressure. (3)Optical and electron microscopy revealed myocardium injury in samples from animals underwent ROSC. However, in comparison with the NTPR group, samples from HTPR group exhibited less damage to the myocardium structure. (4) Apoptosis index (AI) of myocardium was significantly (P < 0.05) higher in NTPR group (42.02%) than in HTPR group (26.39%). (5) Tests of myocardial energy: ATP level (μmol/g) in HTPR was significantly (P < 0.05) higher than NTPR (0.97 ± 0.26 vs. 0.65 ± 0.16). EC in NTPR was significant lower than it in two control groups [(0.33 ± 0.13)% vs. (0.52 ± 0.12)%, (0.55 ± 0.06)%, both P < 0.05], whereas no such difference was found between HTPR [(0.41 ± 0.12)%] and two control groups. (6) 48 hours survival rate in HTPR group was significantly higher (P = 0.043) as compared to NTPR group (100% vs. 60%)., Conclusions: Myocardial dysfunction and myocardium tissue injury both develop in post-resuscitation rabbits with ventricular fibrillation. In these animals, reducing body temperature to the level of mild hypothermia after ROSC may improve the 48 hours survival rate, probably via mechanisms that suppress myocardial cell apoptosis. In our study, such intervention produced no obvious negative impact neither on the cardiac function nor hemodynamics.

Objective: To investigate the impact of prior cerebral infarction (PCI) on in-hospital mortality in patients with Acute Myocardial Infarction (AMI)., Methods: A retrospective analysis of documents of a total of 3572 consecutive patients with AMI admitted to Xuanwu Hospital of Capital Medical University from 2002 Jan. 1 to 2009 Dec. 31 were performed., Results: There were 564 patients (15.8%) with PCI. Compared with the group of without PCI, the group with PCI were substantially older [(69.4 ± 9.9) vs (64.2 ± 12.9) years, P = 0.000], and had a higher prevalence of hypertensive disease, diabetes mellitus, prior myocardial infarction (MI) and non-ST-segment elevation myocardial infarction (NSTEMI) (respectively, 71.0% vs 57.3%; 41.0% vs 25.7%, 12.9% vs 9.5%; 14.9% vs 10.7%, P < 0.01), and a higher in-hospital mortality (16.5% vs 10.0%, P = 0.000). Univariate analysis demonstrated that in-hospital mortality associated with age, gender, extensive anterior MI, anterior MI, diabetes mellitus, prior cerebral infarction, prior myocardial infarction, coronary angiography and percutaneous coronary intervention. Logistic regression analysis found that risk factors were age, extensive anterior MI, anterior MI, diabetes mellitus and prior cerebral infarction, and protective factors were coronary angiography and percutaneous coronary intervention. PCI was independently associated with in-hospital mortality, OR 1.368, 95%CI 1.047 - 1.787, P = 0.022., Conclusion: In patients with acute myocardial infarction, the presence of PCI increases the risk of worse in-hospital outcome.

Polylactic acid (PLA) was used as solid carbon source and biofilm support simultaneously, to investigate the applicability of PLA in the denitrification process. The effect of temperature on denitrification performance was also studied. The IR analysis and SEM observation were performed to investigate the PLA surface structure and biofim morphology. The results showed that when the initial concentration of nitrate nitrogen was 50 mg/L and the temperature was 30 degrees C, the average denitrification rate was 2.6 x 10(-1) mg/(g x h) and nitrate could be completely removed within 13h. Temperature had a significant influence on the denitrification rate. The IR analysis and SEM observation of PLA surface structure confirmed the feasibility of PLA as solid carbon source. The SEM observation of biofim showed that the biofilm was thin and mainly consisted of cocci.

Wheat straw after radiation pretreatment was used as solid carbon source and biofilm support for denitrifying microorganisms. Denitrification performance of radiation-pretreated wheat straw was compared to that of wheat straw without radiation pretreatment. The results showed that the denitrification rate of radiation-pretreated wheat straw was about 20% higher than that of wheat straw without radiation pretreatment. When the initial nitrate concentration was 65.3 mg/L, the denitrification rate using wheat straw after 300 kGy radiation with gamma-ray could reach 0.087 mg/(g x h) and the nitrate removal efficiency was above 90%. Parts of these results were confirmed by the IR analysis and SEM observation of wheat straw surface structure.