The changes of aqueous humor vascular endothelial growth factor and pigment epithelium-derived factor levels before and after intravitreal injection of ranibizumab in proliferative diabetic retinopathy / 中华实验眼科杂志

Background Intraocular neovascularization is a primary cause of visual reduce in proliferative diabetic retinopathy (PDR) , and intravitreal injection of ranibizumab is one of treating approachs.Researching the mechanism of intravitreal injection of ranibizumab for PDR is a new target for the prevention and management of PDR.Objective This study was to determine the levels of vascular endothelial growth factor (VEGF) and pigment epithelium-derived factor (PEDF) in aqueous humor of PDR eyes before and after intravitreai injection of ranibizumab.Methods Self-controlled observational study was designed.Fifteen eyes of 15 PDR patients with type 2 diabetes mellitus were included in Fuzhou General Hospital of Nanjing Military Command from January to August 2014, and 1 eye combined with neovascular glaucoma and iris rubeosis.Aqueous samples of 0.1 ml at each time were collected before and 7 days after the injection of ranibizumab from all patients under the informed consent.The changes of aqueous VEGF and PEDF concentrations were detected and analyzed by enzyme-linked immunosorbent assay.This study complied with Declaration of Helsinki and the protocol was approved by this hospital.Results The freeVEGF concentrations before and 7 days after intravitreal injection were (179.4±136.5) pg/ml and (27.1 ±23.5) pg/ml, respectively, showing a significant reduce after intravitreal injection of ranibizumab (t =4.172, P =0.001).PEDF concentrations before and 7 days after intravitreal injection were (394.0-±237.2) pg/ml and (267.7±199.6) pg/ml, respectively, showing a significant reduce after intravitreal injection of ranibizumab (t =5.443, P =0.000).Intraocular neovascularization vanished after intravitreal injection of ranibizumab and vitrectomy was carried out at the seventh day after intravitreal injection.Conclusions Free VEGF and PEDF levels in aqueous humor appear to be significantly decreased after intravitreal injection of ranibizumab, and ocular neovascularization disappears at same time,which avoids intraoperative bleeding during vitrectomy.

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.

T-CAM, a fastatin-FIII 9-10 fusion protein, potently enhances anti-angiogenic and anti-tumor activity via alphavbeta3 and alpha5beta1 integrins

We made fusion protein of fastatin and FIII 9-10, termed tetra-cell adhesion molecule (T-CAM) that can interact simultaneously with alphavbeta3 and alpha5beta1 integrins, both playing important roles in tumor angiogenesis. T-CAM can serve as a cell adhesion substrate mediating adhesion and migration of endothelial cells in alphavbeta3 and alpha5beta1 integrin-dependent manner. T-CAM showed pronounced anti-angiogenic activities such as inhibition of endothelial cell tube formation, endothelial cell proliferation, and induction of endothelial cell apoptosis. T-CAM also inhibited angiogenesis and tumor growth in mouse xenograft model. The anti-angiogenic and anti-tumoral activity of molecule like fastatin could be improved by fusing it with integrin-recognizing cell adhesion domain from other distinct proteins. The strategy of combining two distinct anti-angiogenic molecules or cell adhesion domains could facilitate designing improved anticancer agent of therapeutic value.

Differential inhibition of endothelial cell proliferation and migration by urokinase subdomains: amino-terminal fragment and kringle domain

The serine protease urokinase-type plasminogen activator (uPA) is implicated in pericellular proteolysis in a variety of physiological and pathological processes including angiogenesis and tumor metastasis. The kringle domain of uPA (UK1) has proven to be an anti-angiogenic molecule with unknown mechanism and amino terminal fragment of uPA (u-ATF) with additional growth factor-like domain can be used for blocking interaction of uPA and uPA receptor. Here, we compared anti-angiogenic activities of these two molecules in vitro and in vivo. The recombinant u-ATF from E. coli and refolded in vitro was found to bind to uPAR with high affinity, whereas E. coli-derived UK1 showed no binding by Biacore analysis. In contrast to UK1 having potent inhibitory effect, u-ATF exhibited low inhibitory effect on bovine capillary endothelial cell growth (ED(50)>320 nM). Furthermore, u-ATF inhibition of VEGF-induced migration of human umbilical vein endothelial cell was far less sensitive (IC(50)= 600 nM) than those observed with UK1, and angiogenesis inhibition was marginal in chorioallantoic membrane. These results suggest that kringle domain alone is sufficient for potent anti- angiogenic activity and additional growth factor-like domain diverts this molecule in undergoing different mechanism such as inhibition of uPA/uPAR interaction rather than undergoing distinct anti- angiogenic mechanism driven by kringle domain.