mRNA Expression Of Vascular Endothelial Growth Factor Receptors Research Articles

A Morphometric Study of Mechanotransductively Induced Dermal Neovascularization

Mechanical stretch has been shown to induce vascular remodeling and increase vessel density, but the pathophysiologic mechanisms and the morphologic changes induced by tensile forces to dermal vessels are poorly understood. A custom computer-controlled stretch device was designed and applied to the backs of C57BL/6 mice (n=38). Dermal and vascular remodeling was studied over a 7-day period. Corrosion casting and three-dimensional scanning electron microscopy and CD31 staining were performed to analyze microvessel morphology. Hypoxia was assessed by immunohistochemistry. Western blot analysis of vascular endothelial growth factor (VEGF) and mRNA expression of VEGF receptors was performed. Skin stretching was associated with increased angiogenesis as demonstrated by CD31 staining and vessel corrosion casting where intervascular distance and vessel diameter were decreased (p<0.01). Immediately after stretching, VEGF dimers were increased. Messenger RNA expression of VEGF receptor 1, VEGF receptor 2, neuropilin 1, and neuropilin 2 was increased starting as early as 2 hours after stretching. Highly proliferating epidermal cells induced epidermal hypoxia starting at day 3 (p<0.01). Identification of significant hypoxic cells occurred after identification of neovessels, suggesting an alternative mechanism. Increased expression of angiogenic receptors and stabilization of VEGF dimers may be involved in a mechanotransductive, prehypoxic induction of neovascularization.

Expression of vascular endothelial growth factor receptors in the endometrium of septate uterus

To compare the messenger RNA (mRNA) expression of vascular endothelial growth factor (VEGF) receptors (KDR, Flt-1, and sflt) in the different endometrial locations of septate uterus and normal uterus. Prospective, observational study. University teaching hospital. Twelve women with complete septate uterus undergoing hysteroscopic metroplasty and 12 women with normal uterus. Endometrial tissue samples were obtained from the endometrium covering the septum and the endometrium lining the lateral wall of the uterus. Moreover, endometrial samples were obtained from patients with normal uterus. Differences in the mRNA expression of VEGF receptors between the endometrial samples of septate and normal uterus. The mRNA expression of VEGF receptors, both KDR and Flt-1, was significantly lower in the endometrium lining the septum as compared with the endometrium covering the lateral wall of septate and normal uterus. Conversely, no differences were observed in mRNA expression in the soluble receptor sflt between the different endometrial samples studied. The results suggest that a local defect of both VEGF transmembranous receptors (KDR and Flt-1) in the endometrium covering the septal area may be responsible for the clinical comportment of this müllerian anomaly.

Effects of gonadotropin-releasing hormone antagonists on the expression of vascular endothelial growth factor and its receptors in a rat model of ovarian hyperstimulation syndrome

Ovarian hyperstimulation syndrome (OHSS) is one of the most life-threatening complications of assisted reproduction treatments. Gonadotropin-releasing hormone antagonists (GnRHanta) are thought to be effective in preventing this complication, and some clinical trials have found lower incidences of OHSS in patients treated with GnRHanta. Our aim was to investigate the effects of GnRHanta on vascular permeability and the expression of vascular endothelial growth factor (VEGF) and its receptors in a rat model of OHSS. An immature early OHSS rat model was established. Three ovarian stimulation protocols were used: pregnant mare serum gonadotropin/human chorionic gonadotropin (hCG) alone, with a GnRHanta, or with a gonadotropin-releasing hormone agonists (GnRHa). Blood and tissue samples were collected at 48 hours after hCG administration. Vascular permeability was evaluated by measuring the Evans-Blue content of extravasated peritoneal fluids. The expression of VEGF and its receptors, including flt-1 and KDR, were detected by reverse transcriptase-polymerase chain reaction and Western blotting. Treatment with both a GnRHanta and a GnRHa resulted in significant reductions in serum estradiol and peritoneal vascular permeability, as well as decreased ovarian expression of VEGF and its two receptors. However, GnRHanta treatment caused a greater reduction in serum estradiol concentrations, and in VEGF receptor mRNA expression than GnRHa. There were no significant reductions in the expression of VEGF or its receptors in extra-ovarian tissues, including the liver, lungs and peritoneum. Our results reveal that GnRHanta are more potent than GnRHa in preventing early OHSS through down-regulation of the expression of VEGF and its receptors in hyperstimulated ovaries.

Beta2-glycoprotein I inhibits vascular endothelial growth factor and basic fibroblast growth factor induced angiogenesis through its amino terminal domain.

Beta-2 glycoprotein I (beta(2)GPI) is a plasma glycoprotein which interacts with various proteins of the coagulation and fibrinolysis system. beta(2)GPI has recently been shown to have anti-angiogenic properties. We undertook this study to investigate the specific domain of beta(2)GPI involved in the anti-angiogenic function and its effect on downstream signaling of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF). Various preparations of beta(2)GPI were used on human umbilical vein endothelial cells (HUVECs) in the absence or presence of VEGF and bFGF. The effect on HUVECs' proliferation, migration and tubule formation in Matrigel matrix was investigated. The effect of beta(2)GPI on the mRNA expression of VEGF receptors and phosphorylation of signaling molecules was also studied. beta(2)GPI is shown in this study to be an anti-angiogenic molecule in vitro by inhibiting VEGF and bFGF-induced proliferation, migration and papillary-like tubule formation of HUVECs. This inhibition was achieved by native, proteolytically clipped and domain deletion mutants, domain I-IV (DI-IV) but not domain II-V (DII-V) of beta(2)GPI. Native beta(2)GPI was found to downregulate the expression of the VEGF receptor KDR/Flk-1 on endothelial cells and to block the phosphorylation of VEGF's downstream effector molecules in the MAPK/ERK and PI3K/Akt/GSK3beta pathways. These results indicate that beta(2)GPI has anti-angiogenic functions which depend on the presence of domain I. This anti-angiogenic activity may have important implications for the therapeutic manipulation of angiogenesis in various disease states.

Growth factor and receptor mRNA expression in the intestine of horses with large colon volvulus: a pilot study

Growth factors (GF) are important for maintenance and repair of intestinal mucosal structure and function, but there have been no studies investigating growth factor (GF) or growth factor receptor (GF-R) mRNA expression in the intestine of horses with large colon volvulus (LCV). (1) To determine mRNA expression for epidermal growth factor (EGF), EGF receptor (EGF-R), insulin-like growth factor-I (IGF), IGF receptor (IGF-R), vascular endothelial growth factor (VEGF) and VEGF receptor (VEGF-R) in the intestine of horses with an LCV compared to normal intestine. (2) To measure the correlation between histological intestinal injury and mRNA expression. In 5 horses, samples were collected from the mid-jejunum (small intestine, SI), pelvic flexure (PF) and right dorsal colon (RDC) prior to creation of the LCV (NORM), 1 h following creation of the LCV (ISCH) and 1 h following correction of the LCV (REPER). In 2 clinical cases of LCV, samples were collected from the PF and RDC. Samples were assessed histologically for the amount of intestinal injury. The mRNA expressions of growth factors and receptors were determined using qRT-PCR. VEGF and VEGF-R mRNA expression was greater in horses with an LCV compared to NORM. Expression of IGF-R mRNA increased in the SI during ISCH and REPER. The increase compared to NORM in VEGF and VEGF-R mRNA expression in horses with LCV may be important in early intestinal healing and may also explain, in part, the increase in vascular permeability in horses with a LCV. Expression of IGF and IGF-R in the SI warrants further investigation and may be important for understanding post operative complications in horses with SI lesions.

Impaired Lung Vascular Endothelial Growth Factor in Extremely Premature Baboons Developing Bronchopulmonary Dysplasia/Chronic Lung Disease

BackgroundPreterm infants exposed to O2 with mechanical ventilation often develop bronchopulmonary dysplasia (BPD), a form of chronic lung disease (CLD). The pathogenesis of BPD/CLD involves dysmorphic microvasculature and disrupted alveolarization....

The mechanisms of hepatic sinusoidal endothelial cell regeneration: A possible communication system associated with vascular endothelial growth factor in liver cells

Vascular endothelial growth factor (VEGF) has been shown to induce proliferation of sinusoidal endothelial cells in primary culture. To elucidate the mechanisms of sinusoidal endothelial cell regeneration in vivo, mRNA expression of VEGF and its receptors, flt-1 and KDR/flk-1, were studied in rat livers. Northern blot analysis revealed that VEGF-mRNA was expressed in hepatocytes immediately after isolation from normal rats. In contrast, non-parenchymal cells, including sinusoidal endothelial cells, expressed VEGF receptor-mRNA. Vascular endothelial growth factor-mRNA expression in hepatocytes was decreased during primary culture, but increased following a peak of DNA synthesis, induced by addition of epidermal growth factor or hepatocyte growth factor to the culture medium at 24 h of plating. In a 70% resected rat liver, VEGF-mRNA expression increased with a peak at 72 h after the operation, and mRNA expression of VEGF receptors between 72 and 168 h. In such a liver, mitosis was maximal in hepatocytes at 36 h and in sinusoidal endothelial cells at 96 h. Also, mRNA expression of both VEGF and its receptors was significantly increased in carbon tetrachloride-intoxicated rat liver compared with normal rat liver. Vascular endothelial growth factor expression was minimal in Kupffer cells isolated from normal rats, but marked in activated Kupffer cells and hepatic macrophages from the intoxicated rats. Vascular endothelial growth factor-mRNA expression was also increased in activated stellate cells from these rats and in the cells activated during primary culture compared with quiescent cells. We conclude that increased levels of VEGF expression in regenerating hepatocytes may contribute to the proliferation of sinusoidal endothelial cells in partially resected rat liver, probably through VEGF receptors up-regulated on the cells. Also, VEGF derived from activated Kupffer cells, hepatic macrophages and stellate cells may be involved in this proliferation in injured rat liver.