The expression changes of peripheral endothelial progenitor cells and Ang-1/Tie2 in patients with pulmonary arterial hypertension / 中华检验医学杂志

Objective To observe the expression changes of peripheral endothelial progenitor cells (EPCs) and Ang-1/Tie2 in patients with pulmonary arterial hypertension (PAH).Methods From Jun 2011 to Dec 2012,45 patients with PAH charged in Affiliated Hospital of Hangzhou Normal University were divided into 3 groups according to mean pulmonary arterial blood pressure (15 per group):mild(Group L),moderate(Group M),and severe(Group S),with another 15 normal people as control group(Group C).The EPCs were isolated from peripheral blood of every patient,number counting using fluorescence activated cell sorter (FACS),function test using cell culture in vitro.Expression of Ang-1 and Tie2 in the peripheral EPCs were measured by RT-PCR or Western-blot.Non normal data was analyzed by non parametric statistical test.Results The statistical discrepancy existed among Group L,M,S and the control in the number of EPCs [32.0 (27.0,37.0),26.0 (19.0,31.0),24.0 (22.0,26.0) vs 40.0 (37.0,51.0),P ＜ 0.05].The ability of migration [32.1 (26.5,37.5),26.8 (22.4,35.4),21.0 (17.8,34.0) vs 39.0 (33.3,42.4),P＜0.05] and adhesion of the EPCs [57.1(50.9,61.8),51.8(45.2,58.7),46.0 (37.2,55.1) vs 64.1 (56.2,75.0),P ＜ 0.05] among study groups and control group was different in statistic,the same with the proliferation activity of EPCs in different groups [0.6 (0.5,0.7),0.5 (0.4,0.6),0.4(0.3,0.5) vs 0.7(0.6,0.8),P ＜0.05].The mRNA expression of Ang-1 and Tie2 in Group M & S were significantly reduced compared with control [4.33 (2.49,4.62) and 2.89 (2.39,3.44) vs 5.31(3.78,6.22),P＜0.05],Tie2 mRNA[1.32(1.23,1.34)and 1.23(1.08,1.42)vs 1.49(1.25,1.66),P ＜ 0.05],and the protein expression of the phosphorylated Tie 2 in Group M &S were decreased [0.16 (0.15,0.24) and 0.12 (0.08,0.18) vs 0.22 (0.19,0.28),P ＜ 0.05].No significant difference of Ang-1 and Tie2 expression was observed between Group L and control [5.42 (4.72,5.95),1.54 (1.43,1.66) and0.23(0.19,0.33),P=0.674,0.867 and 0.674].Conelusion With the severity of PAH,the number and function of circulating EPCs decreased,as consistent with Ang-1 and Tie2 expression changes,suggesting that function decrease of EPCs in patients with PAH may be associated with the decrease of Ang-1/Tie2 expression.

Effect of cerebral ischemic preconditioning on the expressions of angiopoietin-1 and its receptor Tie-2 mRNA in cerebral ischemia in rats / 国际脑血管病杂志

Objective To investigate the effect of cerebral ischemic preconditioning (IP) on the expressions of angiopoietin-1 (Ang-1) and its receptor Tie-2 mRNA in cerebral ischemia in rats.Methods Ninety-nine Wistar rats were randomly assigned to three groups:sham operation (n =9),non-ischemic preconditioning (NIP) (n =45),and IP (n =45).The latter two groups were redivided into 5 subgroups:ischemia-reperfusion 1,3,7,14,and 21 days (n =9 in each group).A model of transient middle cerebral artery occlusion (MCAO) was induced by the intraluminal suture method for focal IP (ischemia for 10 minutes and restoring perfusion).Infarct volume was determined by 2,3,5-triphenyltetrazolium staining.The expression levels of Ang-1/Tie-2 mRNA were detected by in situ hybridization.Results The infarct volumes in the 1 -,3-,and 7-day subgroups of the IP group were significantly smaller than those in the relative subgroups of the NIP group (all P＜ 0.05).The expression of Ang-1 mRNA in the 3- and 7-day subgroups of the IP group and the expression of Tie-2 mRNA in the 1-,3-,and 7-day subgroups of the NIP group were upregulated significantly (all P ＜ 0.05).The infarct volume in the 3-day subgroup of the IP group was reduced most significantly (P ＜ 0.05).The expression of Ang-1 mRNA in the 7-day subgroup was upregulated significantly,and the peak expression of its receptor Tie-2 mRNA appeared at day 3 after IP and continued to day 7.Pearson correlation analysis showed that the expression levels of Ang-1/Tie-2 mRNA were significantly negatively correlated with infarct volume (P ＜0.01).Conclusions The expression of Ang-1/Tie-2 mRNA in the IP group was upregulated within the time window of ischemic tolerance (1 - 7 days after preconditioning),in which Ang-1 may mainly act on the later stage of the cerebral ischemic tolerance.

Association of angiopoietins and soluble angiopoietin receptor Tie-2 with diabetic retinopathy in patients with type 2 diabetes / 中华内分泌代谢杂志

Angiopoietin-2 levels were 5. 80 ( 3. 83-8. 00 ) , 4. 42 ( 2. 56-5. 55 ) , and 2. 75 ( l. 40-4. 64 )ng/ml in type 2 diabetic patients with proliferative retinopathy, patients with non-proliferative retinopathy, and patients without retinopathy, respectively. Statistical significances existed between any two groups (all P ＜0. 01 ). Angiopoietin-1 level in patients with non-proliferative retinopathy was higher than that in patients without retinopathy [10. 57 ( 8. 99-12. 05 ) vs 9. 21 (7. 71-11.2 ) ng/ml, P＜0. 05]. No difference in receptor Tie-2 was found among the 3 groups (P＞0. 05 ). The results suggested that serum angiopoietin-2 level might be associated with the severity of retinopathy in type 2 diabetic patients.

Correlation of angiopoietin-2 and angiopoietin-2 receptor expressions in serum and placenta with preeclampsia / 中华妇产科杂志

Objective To investigate the correlation of the expressions of angiopoietin-2 (Ang-2) and angiopoietin-2 receptor(Tie-2)in serum and placenta with preeclampsia. Methods From May 2009 to April 2010, 62 women with preeclampsia who delivered in Affiliated Hospital of Qingdao University Medical College were recruited in the study, including 30 women with moderate preeclampsia (MPE group) and 32 women with severe preeclampsia (SPE group). Another 30 healthy pregnant women were taken as control group. ELISA was used to measure the serum Ang-2 in these women. Semiquantitative reverse transcription (RT)-PCR was used to investigate the expressions of Ang-2 mRNA and Tie-2 mRNA in placenta. Western blot was used to determine the expression of Ang-2 protein in placenta. Results (1) The serum concentrations of Ang-2 in MPE group and SPE group were (5.4 ± 1.8) μg/L and (5. 1 ± 1.7) μg/L,respectively. Both were significantly lower than that in control group (16. 2 ± 4. 5) μg/L (P<0. 01).There was no significant difference between MPE group and SPE group (P > 0. 05). (2) The expressions of Ang-2 mRNA in placenta of MPE group (2. 1 ± 0. 7) and SPE group (2. 0 ± 0. 6) were both significantly lower than that of control group (5.8 ± 0. 8; P<0. 01). But there was no significant difference in Ang-2 mRNA expression between MPE group and SPE group (P>0. 05). (3) No significant difference was found in the expressions of Tie-2 mRNA in placenta among MPE group (1. 33 ±0. 04), SPE group (1.35 ±0. 05) and control group (1.34 ± 0. 04; P > 0. 05). (4) The expressions of Ang-2 protein in placenta of MPE group (2.0 ± 0. 8) and SPE group (2. 0 ± 0. 8) were both significantly lower than that of control group (5.7 ±0. 9; P <0. 0l), while no significant difference was found between MPE group and SPE group (P >0. 05) . (5) In MPE group and SPE group, the serum concentrations of Ang-2 were positively correlated with the levels of Ang-2 mRNA and Ang-2 protein in placenta(r =0. 651, 0. 627; P <0. 01). Conclusions Decreased expressions of Ang-2 mRNA and Ang-2 protein in placenta reduced serum concentration of Ang-2. Low expression of Ang-2 may be involved in the pathophysiological process of preeclampsia by affecting the formation of placenta in early pregnancy.

Tie2 is tied at the cell-cell contacts and to extracellular matrix by Angiopoietin-1

Angiopoietin-1 (Ang1) binds to and activates Tie2 receptor tyrosine kinase. Ang1-Tie2 signal has been proposed to exhibit two opposite roles in the controlling blood vessels. One is vascular stabilization and the other is vascular angiogenesis. There has been no answer to the question as to how Tie2 induces two opposite responses to the same ligand. Our group and Dr. Alitalo's group have demonstrated that trans-associated Tie2 at cell-cell contacts and extracellular matrix (ECM)-anchored Tie2 play distinct roles in the endothelial cells. The complex formation depends on the presence or absence of cell-cell adhesion. Here, we review how Ang1-Tie2 signal regulates vascular maintenance and angiogenesis. We further point to the unanswered questions that must be clarified to extend our knowledge of vascular biology and to progress basic knowledge to the treatment of the diseases in which Ang1-Tie2-mediated signal is central.

Blockade of airway inflammation and hyper-responsiveness by an angiopoietin-1 variant, COMP-Ang1

Inflammation of the asthmatic airway is usually accompanied by increased vascular permeability and plasma exudation. Angiopoietin-1 (Ang1) has potential therapeutic applications in preventing vascular leakage. Recently, we developed a soluble, stable, and potent Ang1 variant, COMP-Ang1. COMP-Ang1 is more potent than native Ang1 in phosphorylating the tyrosine kinase with immunoglobulin and epidermal growth factor homology domain 2 receptor in lung endothelial cells. We have used a mouse model for allergic airway disease to determine effects of COMP-Ang1 on allergen-induced bronchial inflammation and airway hyper-responsiveness. These mice develop the following typical pathophysiological features of allergic airway disease in the lungs: increased numbers of inflammatory cells of the airways, airway hyper-responsiveness, increased levels of Th2 cell cytokines (IL-4, IL-5, and IL-13), adhesion molecules (intercellular adhesion molecule-1 and vascular cell adhesion molecule-1), and chemokines (eotaxin and RANTES), and increased vascular permeability. Intravenous administration of COMP-Ang1 reduced bronchial inflammation and airway hyper-responsiveness. In addition, the increased plasma extravasation in allergic airway disease was significantly reduced by the administration of COMP-Ang1. These results suggest that COMP-Ang1 attenuates airway inflammation and hyper-responsiveness, prevents vascular leakage, and may be used as a therapeutic agent in allergic airway disease.

Expression and Clinical Significance of Angiopoietin-2 and its Receptor Tie-2 in Invasive Breast Cancer / 한국유방암학회지

PURPOSE: Breast carcinomas are highly malignant tumor that the angiogenesis factor, vascular endothelial growth factor and its receptors are overexpressed. To elucidate the role of Angiopoietin-2 (ANG2) and ANG2 receptor Tie-2 in invasive ductal carcinoma, we examined the expression of ANG2, and Tie-2 at the mRNA and protein levels in human breast cancer cell lines and samples. METHODS: Total RNA from 22 breast cancer patient biopsies were extracted. ANG2 and Tie-2 mRNA expression was measured by means of reverse transcription-PCR assay. RESULTS: RT-PCR indicated that the ANG2 and Tie-2 mRNA levels in carcinoma samples were significantly higher than those of the adjacent non-neoplastic breast tissues. For ANG2 and Tie-2, 41 of 71 invasive ductal carcinomass (58%) showed high expressions in Immunohistochemistry. Immunohistochemical analysis demonstrated that ANG2 and Tie-2 were expressed by both tumor cells and endothelial elements. Expression in tumor cells were confirmed by studying a panel of human breast carcinoma cell lines cultured by RT-PCR. Our study showed that the ANG2 positivity was correlated with axillary lymph node metastasis among the clinicopathological parameter and confirmed that high expressions of ANG2 correlated highly with the axillary lymph node metastases, histological grade, positive PR status, and age, and Tie-2 expression correlated significantly with the p53 status. Moreover, ANG2 and Tie-2 co-expression correlated significantly with the axillary lymph node metastases, compared with ANG2(-)/Tie-2 (-) and ANG2 (+)/Tie-2 (-) or ANG2 (-)/Tie-2 (+) cases. CONCLUSION: These findings suggested that ANG2 and Tie-2 might be involved in the progression of invasive ductal carcinomas through autocrine and paracrine signaling and that it may be clinically useful in selecting patients who could benefit from adjuvant treatment by further study.