Angiogenic factors

MMPS Gelatinase-B, 92 kDa gelatinase Secreted MM P-9 plays a regulatory role in angiogenesis not only through proteolytic activity but also through other downstream angiogenic factors... 

Although tumor cells frequently represent the major source of VEGF-A, tumor-associated stroma is also a site of VEGF production. Tumor-derived PDGF-A may be especially important for the recruitment of an angiogenic stroma that produces VEGF-A and potentially other angiogenic factors. 

A particularly active area of research concerns the elucidation of the mechanisms of refractoriness or resistance to anti-VEGF therapy. Tumor cell-intrinsic or treatment-induced expression of angiogenic factors may be implicated Very recent studies have provided evidence that, at least is some murine models, refractor-inessm to anti-VEGF therapy is related to the ability of the tumor to recruit CDllb+Grl+ myeloid cells, which promote angiogenesis [5]. It remains to be established whether these findings also apply to human tumors. 

New blood vessels, formed from pre-existing vessels, occnrs 7 days post wounding (Park and Barbnl 2004). Potent angiogenic factors snch as vascular endothelial... 

Simonini A, Moscucci M, Muller DW, et al. IL-8 is an angiogenic factor in human coronary atherectomy tissue. Circulation 2000 101(13) 1519—1526. 

The CXC chemokines can be divided into two groups on the basis of a structure/function domain consisting of the presence or absence of three amino acid residues (Glu-Leu-Arg ELR motif) that precedes the first cysteine amino acid residue in the primary structure of these cytokines. The ELR+ CXC chemokines are chemoattractants for neutrophils and act as potent angiogenic factors (6). In contrast, the ELR" CXC chemokines are chemoattractants for mononuclear cells and are potent inhibitors of angiogenesis (Table 1) (6). 

Arenberg DA, Keane MP, DiGiovine B, et al. Epithelial-neutrophil activating peptide (ENA-78) is an important angiogenic factor in non-small cell lung cancer. J Clin Invest 1998 I02(3) 465 172. 

In other chronic inflammatory diseases elevated levels of angiogenic factors were also found. In patients with psoriasis, skin lesions over-expressed IL-8 while the expression of one of the inhibitors of angiogenesis, thrombospondin-1, was downregulated [39]. 

Implantation of polymer matrices that contain angiogenic factors requires quantification of the extent of vessel ingrowth. This can either be analysed immunohistochemically or by haemoglobin/red blood cell count in the tissue. These models generally do not allow analysis of the time course of vascularization since this would require the sacrifice of animals. Application in a dorsal skin fold chamber circumvents this experimental problem, as it provides the opportunity to monitor vessel formation at various time points during the experiment. 

Maier, R., et al. (2006) Application of multiplex cytometric bead array technology for the measurement of angiogenic factors in the vitreous. Mol Vis. 12, 1143-7. 

The rest of the S-shaped tubule retains its epithelial character and segments into proximal tubule, loop of Henle and distal tubule. The cells lose expression of WT1, PAX-2 and n-MYC. Capillaries grow into the cleft in Bowman s capsule. These apparently arise from blood vessels in response to angiogenic factors from the nephron. One such factor is VEGF, known to be secreted by early nephrons. 

Koos RD (1989) Potential relevance of angiogenic factors to ovarian physiology. Semin Reprod Endocrinol, 7 29-33. 

Bobrovnikova-Marjon EV, Marjon PL, Barbash O, Yander Jagt DL, Abcouwer SF. 2004. Expression of angiogenic factors vascular endothelial growth factor and... 

A large number of tumor blood vessels increases the opportunity of the tumor cells to enter the circulation. In fact, the newly formed capillaries usually have a fragmented basement membrane, facilitating easier invasion. In the prevascular phase, with little or no angiogenic activity, the tumor is unable to expand beyond a few cubic millimeters, but once angiogenic factors are released in sufficient number, the onset of angiogenic activity stimulates rapid expansion of the tumor. 

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