Higher Vascular Endothelial Growth Factor Protein Research Articles

The Effect of Collagen-Chitosan-Natrium Hyaluronate Composite on Expression of Vascular Endothelial Growth Factor (Vegf) Protein as Angiogenesis Reaction in Rabbit Corneal Stroma Wound (Experimental Study on Oryctolagus Cuniculus)

Background: Corneal wound healing involves several biological processes, various cytokines and growth factors are released in reaction to tissue damage, including Fibroblast Growth Factor (FGF), Transforming Growth Factor (TGF), Platelet-Derived Growth Factor (PDGF), and Vascular Endothelial Growth Factor ( VEGF). VEGF is proinflammatory cytokines that increase microvascular permeability and plays an essential role in forming new blood vessels in the wound healing process. New blood vessels formed during the healing process can turn into pathological blood vessels, causing metabolic disorders in the cornea, resulting in corneal clouding and blindness. Keratoplasty is the primary therapeutic modality to replace pathological corneal tissue. Due to the limited availability of donors, many alternative therapies have been developed to restore corneal regeneration, one of which is using biomaterials in prosthetic devices with composite materials. Collagen-chitosan-natrium hyaluronate composite is a natural biopolymer considered to have good biocompatibility, biodegradable, and non-toxic properties. Besides being easy to get and produce, the composite is safe and improves corneal tissue regeneration. Methods: Twenty adults New Zealand male white rabbits (30 eyes) were divided into three groups. The first group is the negative control group, without any treatment. The positive control group was the rabbits who had injuries to the stromal layer of the cornea, and the third group was the implant group, which were rabbits who received collagen-chitosan-natrium hyaluronate composite implants after their corneal stromal was injured. On day 14, rabbits were enucleated, and the corneal tissue was examined for immunohistochemistry using anti-VEGF antibodies. Results: The study results showed a significant difference in the percentage of VEGF expression in the positive control group with the implant group was significantly different (p = 0.000, ?> 0.05). High VEGF protein expression did not exceed the positive control group indicating that the wound healing process is ongoing. Conclusion: There was a significant difference in the level of VEGF protein expression between negative control group, positive control group, and implant group. The VEGF level in the implant group was lower than in the positive control group.

Lipo‑prostaglandin E1 modifies cognitive impairment in rats with vascular cognitive impairment by promoting angiogenesis via the VEGF/VEGFR pathway.

The pathological mechanism of vascular cognitive impairment (VCI) involves ischemic lesions in the hippocampus. Prostaglandin E1 (PGE1) serves roles in the promotion of vascular endothelial growth factor (VEGF) expression, angiogenesis and enhances blood flow to ischemic regions. However, the effect of PGE1 on cognitive function in VCI rats and the underlying mechanism are unknown. In the current study, learning and memory function in VCI rats treated by lipo-PGE1 injection was assessed through Morris Water Maze test. Furthermore, the histological alterations, blood vessel numbers in the hippocampal CA1 region and relative VEGF protein and mRNA expression were researched. The results confirmed that VCI rats treated with lipo-PGE1 presented improved cognitive function, less neuronal cell loss, a greater number of blood vessels in the hippocampal region and higher VEGF protein and mRNA expression. However, the role of lipo-PGE1 in VCI rats can be inhibited by SU5416 (a specific VEGFR2 antagonist). The results indicated that lipo-PGE1 may alleviate cognitive deficits in VCI rats. The underlying mechanism may be associated with angiogenesis promoted by lipo-PGE1, which may involve the VEGF/VEGFR pathway. These findings may have therapeutic implications for cognitive impairment induced by hypoperfusion or chronic ischemic lesions.

Efficient plasmid-mediated gene transfection of ovine bone marrow mesenchymal stromal cells

Given the close similarity between ovine and human cardiomyocytes, sheep models of myocardial infarction and heart failure are increasingly used in studies of stem cell-mediated heart regeneration. In these studies, mesenchymal stromal cells (MSCs) are frequently employed. To enhance the paracrine effects of these MSCs, ex vivo transfection with genes encoding growth factors has been proposed. Although viral vectors exhibit higher transfection efficiency than plasmids, they entail the risks of uncontrolled transgene expression and immune reactions that preclude repeated administration. Our aim was to optimize the efficiency of plasmid-mediated transfection of ovine MSCs, while preserving cell viability. Varying amounts of diverse cationic lipids were used to obtain the reagent-to-DNA mass ratio showing highest luciferase activity. Transfection efficiency (flow cytometry) was tested on plasmid-green fluorescent protein-transfected MSCs at increasing DNA mass. Lipofectamine LTX 5 μL and Plus reagent 4 μL with 2 μg of DNA yielded 42.3 ± 4.7% transfection efficiency, while preserving cell viability. Using these transfection conditions, we transfected MSCs with a plasmid encoding human vascular endothelial growth factor (VEGF) and found high VEGF protein concentrations in the culture supernatant from day 2 (1968 ± 324 pg/mL per μg DNA) through at least day 12 (888 ± 386 pg/mL per μg DNA) after transfection. Plasmid-mediated transfection of ovine MSCs to over-express paracrine heart-regenerative growth factors is feasible and efficient and overcomes the risks and limitations associated with the use of viral vectors.

Differential effects of Th1 versus Th2 cytokines in combination with hypoxia on HIFs and angiogenesis in RA

IntroductionHypoxia and T-helper cell 1 (Th1) cytokine-driven inflammation are key features of rheumatoid arthritis (RA) and contribute to disease pathogenesis by promoting angiogenesis. The objective of our study was to characterise the angiogenic gene signature of RA fibroblast-like synoviocytes (FLS) in response to hypoxia, as well as Th1 and T-helper cell 2 (Th2) cytokines, and in particular to dissect out effects of combined hypoxia and cytokines on hypoxia inducible transcription factors (HIFs) and angiogenesis.MethodsHuman angiogenesis PCR arrays were used to screen cDNA from RA FLS exposed to hypoxia (1% oxygen) or dimethyloxalylglycine, which stabilises HIFs. The involvement of HIF isoforms in generating the angiogenic signature of RA FLS stimulated with hypoxia and/or cytokines was investigated using a DNA-binding assay and RNA interference. The angiogenic potential of conditioned media from hypoxia-treated and/or cytokine-treated RA FLS was measured using an in vitro endothelial-based assay.ResultsExpression of 12 angiogenic genes was significantly altered in RA FLS exposed to hypoxia, and seven of these were changed by dimethyloxalylglycine, including ephrin A3 (EFNA3), vascular endothelial growth factor (VEGF), adipokines angiopoietin-like (ANGPTL)-4 and leptin. These four proangiogenic genes were dependent on HIF-1 in hypoxia to various degrees: EFNA3 >ANGPTL-4 >VEGF >leptin. The Th1 cytokines TNFα and IL-1β induced HIF-1 but not HIF-2 transcription as well as activity, and this effect was additive with hypoxia. In contrast, Th2 cytokines had no effect on HIFs. IL-1β synergised with hypoxia to upregulate EFNA3 and VEGF in a HIF-1-dependent fashion but, despite strongly inducing HIF-1, TNFα suppressed adipokine expression and had minimal effect on EFNA3. Supernatants from RA FLS subjected to hypoxia and TNFα induced fewer endothelial tubules than those from FLS subjected to TNFα or hypoxia alone, despite high VEGF protein levels. The Th2 cytokine IL-4 strongly induced ANGPTL-4 and angiogenesis by normoxic FLS and synergised with hypoxia to induce further proangiogenic activity.ConclusionThe present work demonstrates that Th1 cytokines in combination with hypoxia are not sufficient to induce angiogenic activity by RA FLS despite HIF-1 activation and VEGF production. In contrast, Th2 cytokines induce angiogenic activity in normoxia and hypoxia, despite their inability to activate HIFs, highlighting the complex relationships between hypoxia, angiogenesis and inflammation in RA.

Significance of a reversal expression of the angiopoietin-1 and 2 in oral squamous cell carcinoma

To investigate the significance of Angiopoietin-1 (Ang-1), Angiopoietin-2 (Ang-2) expression in angiogenesis, vessel maturation, progress and prognosis of oral squamous cell carcinoma (OSCC). The expression of Ang-1, Ang-2, vascular endothelial growth factor (VEGF), CD34 and alpha-smooth muscle actin (alpha-SMA) were studied in 62 human OSCCs, 30 adjacent noncancerous oral tissues and 10 normal oral mucosa by conventional immunohistochemistry. Microvessel density (MVD) and vessel maturation index (VMI) were also assessed with double-labeling immunohistochemistry staining against CD34, a marker of pan-endothelial cells, and that against alpha-SMA, a marker of mural cells (pericytes/smooth muscle cells). The images were analyzed with BioMias system. Ang-1/Ang-2 protein expression ratio were significantly lower in OSCC than that in adjacent noncancerous oral tissues and normal oral mucosa (t were -5.42 and -6.234, all P<0.01). There were significantly different Ang-1/Ang-2 protein expression ratio in different tumor' lymph node metastasis status and MVD groups and VMI groups, respectively (t were 3.421, -3.221, 3.824, all P<0.01). The patients with low Ang-1/Ang-2 protein expression ratio and high VEGF protein expression were found to have a significantly higher MVD when compared to others (t were 2.055, 2.345, 2.985, all P<0.05). Ang-1/Ang-2 protein expression ratio had a tendency to be a prognostic factor (chi2=3.383, P=0.066). The reversion of Ang-1 and Ang-2 expression may plays an important role in the development and progression of OSCC. It is closely associated with the angiogenesis, vessel maturation and prognosis of OSCC.

Expression and tissue concentration of vascular endothelial growth factor, its receptors, and localization in the bovine corpus luteum during estrous cycle and pregnancy.

The presence of vascular endothelial growth factor (VEGF) in the ovary has been reported in a number of species. The objective of the present study was to demonstrate the expression of VEGF, VEGF receptor (R)-1, and VEGFR-2 in detail by different methodological approaches in bovine corpora lutea (CL) obtained from different stages of the estrous cycle and during pregnancy. VEGF and VEGF receptor transcripts were analyzed by reverse transcription-polymerase chain reaction (RT-PCR) and ribonuclease protection assay. All components of the VEGF system were found in the bovine CL during the estrous cycle and pregnancy. Analysis of VEGF transcript by RT-PCR shows that CL tissues expressed predominantly the smallest isoforms (VEGF(121) and VEGF(165)). The highest mRNA expression for VEGF and VEGFR-2 mRNA was detected during the early luteal phase, followed by a significant decrease of expression during the mid and late luteal phase and a further decrease of VEGF mRNA after regression. During pregnancy, high levels of expression were always present. In contrast, no significant change in VEGFR-1 mRNA expression during the estrous cycle and pregnancy was found. The VEGF protein concentration in CL tissue was significantly higher (20.9-23.4 ng/g wet weight) during the early luteal phase (Days 1-7), followed by a decrease at the late luteal phase (14.3-18.7 ng/g wet weight) and, especially, after CL regression (2.8 ng/g wet weight). However, relatively high levels were found during pregnancy (10.1 ng/g wet weight). As achieved by immunohistochemistry, VEGF protein was localized predominantly in luteal cells. High VEGF protein and transcript concentrations and increased VEGFR-2 expression during the early luteal phase coincided with luteal vascularization. These results suggest an important role of VEGF in angiogenesis of the newly formed CL. The high VEGF mRNA expression and protein levels during matured vasculature in the mid-stage CL and pregnancy also suggest also a survival function for endothelial cells.

Correlation of total VEGF mRNA and protein expression with histologic type, tumor angiogenesis, patient survival and timing of relapse in non-small-cell lung cancer.

We have quantified the expression of all 4 isoforms of vascular endothelial growth factor (VEGF) mRNA in non-small-cell lung cancer (NSCLC) using a new kinetic quantitative PCR method, real-time quantitative (RTQ) RT-PCR, and investigated the association between VEGF expression at the mRNA and protein levels and the clinicopathologic variables, tumor angiogenesis, patient survival and timing of relapse. Surgical tumor specimens from 72 NCSLC patients (37 squamous-cell carcinomas, 35 adenocarcinomas) were examined. Twenty-eight patients had stage I, 10 stage II and 34 stage IIIA or IIIB disease. Total VEGF mRNA (all 4 isoforms) was quantified by RTQ RT-PCR, while VEGF protein expression and microvessel number in tumors were assessed immunohistochemically. VEGF mRNA was detected in all 72 tumor samples at significantly higher levels than in adjacent normal tissue. Tumoral VEGF mRNA levels correlated strongly with the VEGF protein staining score and microvessel count. Adenocarcinomas showed significantly higher VEGF mRNA expression and a higher protein staining score than squamous-cell carcinomas. High tumoral VEGF mRNA expression was associated with advanced (IIIA or IIIB) tumor stage, lymph node metastasis, high tumoral microvessel counts, short patient survival (<24 months) and early relapse (<12 months), while a high VEGF protein staining score was associated with high tumoral microvessel counts, short patient survival and early relapse. Patients with high tumoral levels of both VEGF mRNA and protein had significantly shorter survival and earlier relapse. In multivariate analysis, the VEGF protein staining score and nodal status were the most important independent predictors of survival and recurrence. We conclude that RTQ RT-PCR is a sensitive method for detecting and quantifying VEGF mRNA expression in NSCLC and that the expression levels of total VEGF mRNA and protein in NSCLC are strongly associated with histologic type, tumor angiogenesis, survival and timing of relapse. High VEGF expression in adenocarcinomas may contribute to their greater metastatic potential.

Vascular Endothelial Growth Factor is a Predictor of Relapse and Stage Progression in Superficial Bladder Cancer

Tumor development is angiogenesis dependent, and vascular endothelial growth factor (VEGF) is a key growth factor in this process. We demonstrate that high expression of VEGF mRNA in 55 superficial bladder cancers was associated with earlier recurrence (P = 0.001; hazard ratio, 3.09) and progression to a more invasive phenotype (P = 0.02; hazard ratio, 5.33). VEGF mRNA expression correlated with protein levels in superficial tumors (r = 0.59, P = 0.003) and normal bladder (r = 0.65, P < 0.05), although the ratio of VEGF protein to mRNA was elevated in tumors compared to normal bladder (P = 0.004), suggesting posttranscriptional regulation. In this study, VEGF is implicated as a major downstream mediator of the effects of the p53 tumor suppressor gene by the association between high p53 protein (determined immunochemically) and high VEGF protein and mRNA expression (P < 0.02), although in cases without high p53 protein expression, high VEGF mRNA also predicts a poor prognosis. The relationship between VEGF and early tumor recurrence suggests that seeding via angiogenesis may be a major mechanism in the pathogenesis of recurrence. These studies indicate that VEGF can predict the behavior of superficial bladder tumors and is a therapeutic target for intravesical therapy.