Browsing by Subject "Tie1"

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  • Huuska, Nora (Helsingin yliopisto, 2018)
    TAUSTA: Verisuonten uudismuodostuksen, läpäisevyyden ja rappeutumisen säätelyssä avainasemassa on Angiopoietiini-Tie-järjestelmä, joka koostuu angiopoietiineista 1-4 (Ang1-4) sekä niiden reseptoreista Tie1 ja Tie2. Ang1:n aikaansaama Tie-reseptorien aktivaatio johtaa verisuonten endoteelisolujen välisten sidosten tiukentumiseen ja homeostasian ylläpitoon. Ang2 puolestaan pystyy salpaamaan Tie2-reseptorin, jolloin verisuonten läpäisevyys lisääntyy ja endoteeli alkaa rappeutua. Paradoksaalisesti Ang2 pystyy myös aktivoimaan Tie1:n tietyissä olosuhteissa, jolloin verisuonten läpäisevyys vähenee. TAVOITTEET: Tämän tutkimuksen tarkoituksena oli selvittää Ang2:n yli-ilmentymisen ja Tie1-poistogeenisyyden vaikutusta verisuonten läpäisevyyteen hiirten keuhkokudoksessa. Lisäksi tutkittiin anti-Tie1 (DX2240) ja anti-Ang2 (MEDI3617) vasta-aineiden vaikutusta verisuonten läpäisevyyteen ja tulehdusreaktion voimakkuuteen LPS-indusoidussa verenmyrkytyksessä. MENETELMÄT: Määritettiin valkosolujen, punasolujen ja fibrinogeenin määrä immunohistokemiallisten värjäysten avulla Ang2:ta yli-ilmentävien hiirten, Tie1-poistogeenisten hiirten ja näiden yhdistelmähiirten keuhkoissa. Lisäksi määritettiin keuhkolaskimoiden seinämien paksuus sekä nanopartikkelien vuoto anti-Tie1 ja anti-Ang2 vasta-aineita saaneiden hiirten keuhkoissa tulehduksen ja verisuonten läpäisevyyden arvioimiseksi. TULOKSET: Ang2:n yli-ilmentymisen ja Tie1-poistogeenisyyden ei havaittu aiheuttavan merkittävää eroa verisuonten läpäisevyydessä. Anti-Tie1 ja anti-Ang2-vasta-aineet eivät myöskään vähentäneet merkittävästi verisuonten läpäisevyyttä verenmyrkytyksessä.
  • Tiainen, Leena; Korhonen, Emilia A.; Leppänen, Veli-Matti; Luukkaala, Tiina; Hämäläinen, Mari; Tanner, Minna; Lahdenperä, Outi; Vihinen, Pia; Jukkola, Arja; Karihtala, Peeter; Aho, Sonja; Moilanen, Eeva; Alitalo, Kari; Kellokumpu-Lehtinen, Pirkko-Liisa (2019)
    BackgroundAngiopoietin growth factors (Angs) regulate angiogenesis and lymphangiogenesis by binding to the endothelial Tie2 receptor. Ang2 expression is elevated in tissue hypoxia and inflammation, which also induce cleavage of the extracellular domain of the orphan Tie1 receptor. Here we have examined if the concentrations of Ang2 and the soluble extracellular domain of Tie1 in patient plasma are associated with the prognosis of patients with metastatic breast cancer.MethodsPlasma Tie1 and Ang2 levels were measured in metastatic breast cancer patients treated in a phase II trial with a taxane-bevacizumab combination chemotherapy in the first-line treatment setting. They were analyzed before treatment, after 6weeks and 6months of treatment, and at the final study visit. Using the median concentrations as cutoffs, Tie1 and Ang2 data were dichotomized into low and high concentration groups. Additionally, we analyzed Tie1 concentrations in plasma from 10 healthy women participating in a breast cancer primary prevention study.ResultsPlasma samples were available from 58 (89%) of the 65 patients treated in the trial. The baseline Tie1 levels of the healthy controls were significantly lower than those of the metastatic patients (p
  • Tiainen, Leena; Korhonen, Emilia A; Leppänen, Veli-Matti; Luukkaala, Tiina; Hämäläinen, Mari; Tanner, Minna; Lahdenperä, Outi; Vihinen, Pia; Jukkola, Arja; Karihtala, Peeter; Aho, Sonja; Moilanen, Eeva; Alitalo, Kari; Kellokumpu-Lehtinen, Pirkko-Liisa (BioMed Central, 2019)
    Abstract Background Angiopoietin growth factors (Angs) regulate angiogenesis and lymphangiogenesis by binding to the endothelial Tie2 receptor. Ang2 expression is elevated in tissue hypoxia and inflammation, which also induce cleavage of the extracellular domain of the orphan Tie1 receptor. Here we have examined if the concentrations of Ang2 and the soluble extracellular domain of Tie1 in patient plasma are associated with the prognosis of patients with metastatic breast cancer. Methods Plasma Tie1 and Ang2 levels were measured in metastatic breast cancer patients treated in a phase II trial with a taxane-bevacizumab combination chemotherapy in the first-line treatment setting. They were analyzed before treatment, after 6 weeks and 6 months of treatment, and at the final study visit. Using the median concentrations as cutoffs, Tie1 and Ang2 data were dichotomized into low and high concentration groups. Additionally, we analyzed Tie1 concentrations in plasma from 10 healthy women participating in a breast cancer primary prevention study. Results Plasma samples were available from 58 (89%) of the 65 patients treated in the trial. The baseline Tie1 levels of the healthy controls were significantly lower than those of the metastatic patients (p < 0.001). The overall survival of the patients with a high baseline Tie1 level was significantly shorter (multivariate HR 3.07, 95% CI 1.39–6.79, p = 0.005). Additionally, the progression-free survival was shorter for patients with a high baseline Tie1 level (multivariate HR 3.78, 95% CI 1.57–9.09, p = 0.003). In contrast, the baseline Ang2 levels had no prognostic impact in a multivariate Cox proportional hazard regression analysis. The combined analysis of baseline Tie1 and Ang2 levels revealed that patients with both high Tie1 and high Ang2 baseline levels had a significantly shorter overall survival than the patients with low baseline levels of both markers (multivariate HR for overall survival 4.32, 95% CI 1.44–12.94, p = 0.009). Conclusions This is the first study to demonstrate the prognostic value of baseline Tie1 plasma concentration in patients with metastatic breast cancer. Combined with the results of the Ang2 analyses, the patients with both high Tie1 and Ang2 levels before treatment had the poorest survival. Trial registration Clinicaltrials.gov: NCT00979641, registration date 19-DEC-2008. The regional Ethics Committee: R08142M, registration date 18-NOV-2008.