Vascular Endothelial Growth Factor Activity Research Articles

Enhanced Brain Clearance of Tau and Amyloid-β in Alzheimer's Disease Patients by Transcranial Radiofrequency Wave Treatment: A Central Role of Vascular Endothelial Growth Factor (VEGF).

While drainage/removal of fluid and toxins from the brain by cerebrospinal fluid (CSF) directly into venous blood is well-known, a second drainage route has recently been (re)discovered-meningeal lymphatic vessels (mLVs)-which are responsible for up to half of total brain fluid/toxin drainage. The cytokine vascular endothelial growth factor (VEGF) increases mLV diameter and numbers to increase mLV drainage, resulting in increased mLV drainage. Alzheimer's disease (AD) is characterized by low plasma and CSF levels of VEGF. To determine if non-invasive transcranial radiofrequency wave treatment (TRFT), through modulation of VEGF levels in blood and CSF, can affect removal of toxins tau and amyloid-β (Aβ) from the brain. Eight mild/moderate AD subjects were given twice-daily 1-hour TRFT sessions at home by their caregivers. Blood and CSF samples were taken at baseline and following completion of 2 months of TRFT. In plasma and/or CSF, strong baseline correlations between VEGF levels and AD markers (t-tau, p-tau, Aβ1-40, Aβ1-42) were eliminated by TRFT. This effect was primarily due to TRFT-induced increases in VEGF levels in AD subjects with low or unmeasurable "baseline" VEGF levels. These increased VEGF levels were associated with increased clearance/drainage of tau and Aβ from the brain, likely through VEGF's actions on mLVs. A new mechanism of TRFT is identified (facilitation of brain tau and Aβ clearance via VEGF) that is likely contributory to TRFT's reversal of cognitive impairment in AD subjects. TRFT may be particularly effective for cognitive benefit in AD subjects who have low VEGF levels.

CalDAG-GEFIII controls Ca2+ entry via Rap1 and H-Ras, triggering distinct signaling pathways

Objective: Small GTPase Rap1 plays key functions in endothelium, including controlling Ca2+-dependent endothelial function (NO release). Our recent study suggests the Rap1A isoform restricts Ca2+ entry, to control eNOS activity. The activity of Rap1, a GDP to GTP switch, is controlled by Guanine Nucleotide Exchange Factors (GEFs). However, how Rap1 is activated in the context of Ca2+ signaling and regulation of eNOS activity is unknown. A Ca2+ and diacylglycerol (DAG)-activated CalDAG-GEFIII can activate Ha-Ras, R-Ras, and Rap1, but its functions in endothelial cells (ECs), and the signaling specificity of CalDAG-GEFIII through Rap1 and Ras pathways are not well understood. Our study aims to elucidate the role of CalDAG-GEFIII in regulating Ca2+ signaling in ECs. Approach and Results: To determine relative expression of Rap1 GEFs in ECs in different tissues, we reanalyzed the single-cell RNA sequencing (scRNA-Seq) data from eleven publicly available scRNA-seq datasets. We found RasGRP3 (encoding CalDAG-GEFIII) was highly expressed compared to other Rap1-GEFs in endothelial cells from different organs. To examine the involvement of CalDAG-GEFIII Rap1 and Ras activation in heart ECs, we determined the effect of on Vascular Endothelial Growth Factor (VEGF)-induced Rap1-GTP and Ras-GTP loading using pull-down assay. Knockdown of RasGRP3 blocked Rap1 and Ras activation downstream from VEGFR2, suggesting CalDAG-GEFIII acts as a GEF (activator) of both Rap1 and Ras in endothelial cells. To examine the involvement of CalDAG-GEFIII and H-Ras in Ca2+ signaling in ECs, we measured VEGF-induced intracellular Ca2+ using Fura2 dye, an intracellular Ca2+ indicator, in siRasGRP3, siH-Ras (most highly expressed Ras isoform) and siControl HUVECs. We found that Ca2+ release unchanged, but Ca2+ entry was increased in siRasGRP3 and siRas ECs, similarly to what we had found in siRap1A ECs. This suggests that Ras, like Rap1, limits ATP and TG-induced Ca2+ entry in HUVECs and that CalDAG-GEFIII may act upstream from both Rap1 and Ras. The elevated Ca2+ entry in siRap1A, siRasGRP3 ECs was partially normalized by exogenous expression of constitutively activated Rap1A or activation of Rap1 A by cAMP-dependent GEF, Epac. This indicates that Rap1A controls Ca2+ entry both acutely via a signaling mechanism, and at the transcript level. To determine the involvement of CalDAG-GEFIII in signaling by Rap1 and Ras, we determined the impact of siRNA knockdown of siRap1, siRas and siRasGRP3 on Ser1177 eNOS phosphorylation and Thr202/Tyr204 ERK phosphorylation in response to VEGF stimulation. Knockdown of RasGRP3 or Rap1 attenuated VEGF-induced Ser-1177 eNOS phosphorylation, while knockdown of RasGRP3 or Ras, but not Rap1, inhibited ERK phosphorylation in response to VEGF. Conclusions: Rap1 and Ras, activated downstream from CalDAG-GEFIII in response to VEGF activation, limit agonist-induced Ca2+ entry in endothelial cells. CalDAG-GEFIII promotes eNOS phosphorylation through Rap1B and promotes ERK phosphorylation via Ras, independent of Rap1. This suggests that CalDAG-GEFIII acts in two separate pathways, that are Rap1 and Ras dependent. NIH NHLBI: R01HL111582. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Validation of an enzyme-linked immunosorbent assay test-system for bevacizumab concentration determing in biological fluids

Introduction. One of the reasons for the development of many diseases primarily malignant is the increased expression of Vascular Endothelial Growth Factor (VEGF). Bevacizumab is a drug that neutralizes the biological activity of VEGF. The molecular structure of bevacizumab is a recombinant humanized antibody. Its use reduces vascularization in the foci of increased VEGF expression which slows down tumor growth and also helps restore vision in a number of ophthalmic diseases. To determine the concentration of bevacizumab in human biological fluids a test system based on Enzyme-linked Immunosorbent Assay (ELISA) is presented.Aim. Aim of this study is the validation of this test system.Materials and methods. Blank sera of volunteers, bevacizumab solution, enzyme-linked immunosorbent assay, solid-phase sandwich ELISA kit, microplate photometer.Results and discussion. The following characteristics of the test system were determined: the lower limit of quantification is 2.0 mcg/ml, the upper calibration range is up to 200 mcg/ml, the accuracy and precision within one series and between series does not exceed 20 %, and the total error of the method – 30 %, short-term stability for samples at room temperature – 6 hours, long-term stability – 14 days at –20 °C, the ability to freeze/thaw of samples is up to three times, the ability to determine samples with a concentration above the upper calibrator after diluting in 2 times.Conclusion. The results obtained fully comply with international acceptance criteria and allow the use of the ELISA test system manufactured by LLC "Probiotek" for use in the field of clinical laboratory diagnostics.

Formation of Inclusion Complex of Curcumin and Tetrahydrocurcumin Prevents Angiogenesis by Inhibiting VEGF Activity: An in-Silico Study

Curcumin and tetrahydrocurcumin (THC) are known for their anticancer properties, but limited solubility in water hinders their effectiveness against cancer. In this study, we conducted an in silico exploration of β-cyclodextrin's potential to form inclusion complexes with curcumin or THC. The aim of this study was to assess the potential of curcumin and THC inclusion complexes to inhibit vascular endothelial growth factor (VEGF) signaling pathway, a key element in carcinogenesis. The in silico analysis involved multiple stages, such as bioactive compound preparation, biological activity prediction, 3D structure retrieval of VEGF and VEGFR, protein-ligand docking, and visualization. The results of the study demonstrated that both the curcumin- and THC-inclusion complexes exhibit a lower requirement for binding free energy to interact with VEGFR compared to curcumin or THC molecules alone. When VEGFR binds with curcumin, the curcumin-inclusion complex, or the THC-inclusion complex before interacting with VEGF, there is a notable increase in the binding free energy for the VEGF-VEGFR interaction. Specifically, the presence of THC-inclusion complex demonstrates the highest binding free energy for the VEGF-VEGFR interaction. The molecular dynamic simulation study shows that when VEGFR binds with curcumin, curcumin-inclusion complex, or THC-inclusion complex, the fluctuation of amino acid residues in VEGFR decreases compared to the VEGFR protein structure before binding with these molecules. In conclusion, this study suggests that the formation of inclusion complexes holds considerable promise for enhancing the anticancer potential of curcumin and THC by augmenting their anti-angiogenic activity.

Engineered therapeutic antibodies with mannose 6-phosphate analogues as a tool to degrade extracellular proteins.

Inducing the degradation of pathological soluble antigens could be the key to greatly enhancing the efficacy of therapeutic monoclonal antibodies (mAbs), extensively used in the treatment of autoimmune and inflammatory disorders or cancer. Lysosomal targeting has gained increasing interest in recent years due to its pharmaceutical applications far beyond the treatment of lysosomal diseases, as a way to address proteins to the lysosome for eventual degradation. Mannose 6-phosphonate derivatives (M6Pn), called AMFA, are unique glycovectors that can significantly enhance the cellular internalization of the proteins conjugated to AMFA via the cation-independent mannose 6-phosphate receptor (M6PR) pathway. AMFA engineering of mAbs results in the generation of a bifunctional antibody that is designed to bind both the antigen and the M6PR. The improvement of the therapeutic potential by AMFA engineering was investigated using two antibodies directed against soluble antigens: infliximab (IFX), directed against tumor necrosis factor α (TNF-α), and bevacizumab (BVZ), directed against the vascular endothelial growth factor (VEGF). AMFA conjugations to the antibodies were performed either on the oligosaccharidic chains of the antibodies or on the lysine residues. Both conjugations were controlled and reproducible and provided a novel affinity for the M6PR without altering the affinity for the antigen. The grafting of AMFA to mAb increased their cellular uptake through an M6PR-dependent mechanism. The antigens were also 2.6 to 5.7 times more internalized by mAb-AMFA and rapidly degraded in the cells. Additional cell culture studies also proved the significantly higher efficacy of IFX-AMFA and BVZ-AMFA compared to their unconjugated counterparts in inhibiting TNF-α and VEGF activities. Finally, studies in a zebrafish embryo model of angiogenesis and in xenografted chick embryos showed that BVZ-AMFA was more effective than BVZ in reducing angiogenesis. These results demonstrate that AMFA grafting induces the degradation of soluble antigens and a significant increase in the therapeutic efficacy. Engineering with mannose 6-phosphate analogues has the potential to develop a new class of antibodies for autoimmune and inflammatory diseases.

Role of Vascular Endothelial Growth Factor as a Potential Biomarker in Congenital Heart Defects: A Systematic Review.

Several studies have investigated the role of vascular endothelial growth factor (VEGF) variants, serum levels, and correlations with other extrinsic factors in congenital heart defects (CHDs); however, the findings need confirmation. The present systematic review evaluates the association between CHDs and genetic polymorphisms and serum expressions. Relevant literature was searched through electronic databases using keywords and MeSH terms. VEGF activity was comparatively assessed between cyanotic and acyanotic CHDs, and the association between different polymorphisms and heart defects was evaluated. We ultimately evaluated 12 studies regarding the association between VEGF serum patterns and found that serum VEGF levels were upregulated or downregulated in correlation with hypoxia and hemoglobin levels and were significantly associated with cyanotic CHDs compared with acyanotic CHDs. Our results also showed a significant role for different single-nucleotide polymorphisms, including rs699947, rs2010963, and rs3025039. The findings of the current study suggested a significant association between CHDs and VEGF genetic polymorphisms or varied serum levels. Nevertheless, more comprehensive studies may provide conclusive results and valuable insights into the pathogenesis of CHDs and relevant treatment strategies.

Ангиогенные и антиангиогенные факторы в генезе аномалий плацентации

Aim. To evaluate the role of placenta growth factor (PlGF), vascular endothelial growth factor (VEGF) and soluble fms-like tyrosine kinase-1 (sFlt-1) in the pathogenesis of placental adherent and invasive pathology (PAIP). Key points. sFlt-1 is an inhibitor of the angiogenic action of PLGF and VEGF. The concentration of sFlt-1 in the blood serum of patients with PAIP was significantly lower than in women with physiological pregnancy in all the studies presented in this review. Only two studies have determined thresholds for serum markers for PAIP, but according to the results of the meta-analysis, they had large differences. Despite the known proangiogenic function of VEGF and PlGF, a significant correlation between their levels was not found either in serum by enzyme immunoassay or in expression on chorionic cells, decidual tissue and myometrium in abnormal placental invasion. Conclusion. Further study of the role of VEFG, PlGF and sFlt-1 in the pathogenesis of PAIP is needed to find their threshold levels in the blood and use as a diagnostic markers. Keywords: placental adherent and invasive pathology, placenta previa, vascular endothelial growth factor, placenta growth factor, soluble fms-like tyrosine kinase-1, vascular endothelial growth factor receptors-l and -2.

Oxidative Stress Participates in Age-Related Cataract Formation by Disrupting Connection between Lens Epithelial Cells through c-Src/VEGF Pathway

Purpose To observe the effects of oxidative stress on vascular endothelial growth factor (VEGF) and connections of lens epithelial cells. Methods Human lens epithelium of patients with age-related cataract (ARC), both SRA01/04 cells and whole mice lens stimulated by H2O2 were employed. VEGF in human aqueous humor of ARC-patients and the supernatant of SRA01/04 cells was determined by ELISA. The expressions of VEFG in human lens epithelium were detected by immunofluorescence staining. Multiple linear regression analysis and spearman rank-order correlation were used to determine the associations between VEGF and parameters of ARC individuals. In H2O2-induced SRA01/04 cells, Catalase (CAT), PP1 (inhibitor of c-Src kinase) and Avastin (VEGF antibody) were used to inhibit the effects of H2O2, activation of c-Src kinase and VEGF, which were detected by Western blot. The alterations of ZO-1 and N-cadherin were tested by immunofluorescence staining and Western blot. In H2O2-induced whole lens, the changes of opacification area in different treatment of inhibitors were observed. Results The secretion of VEGF in aqueous humor and expression of VEGF in the lens epithelium of ARC patients increased significantly with age. In H2O2-induced SRA01/04 cells, the VEGF in the supernatant was increased with the culture duration and the dose of H2O2. The expressions of p-Src418 and VEGF were also up-regulated, whereas the expressions of ZO-1 and N-cadherin were down-regulated. CAT effectively prevented these changes induced by H2O2, while PP1 inhibited not only p-Src418 but also up-regulation of VEGF, Avastin partially inhibited VEGF up-regulation. Both PP1 and Avastin prevented down-regulation of ZO-1 and N-cadherin, respectively, but Avastin combined with PP1 had no significant synergistic effects. In H2O2-induced cataract, CAT prevented development of opacification area effectively, and PP1 and Avastin did partially. Conclusions Oxidative stress disrupts connections of lens epithelial cells by activating c-Src/VEGF, inhibiting which may prevent cataract.

Effects of SU5416 on angiogenesis and the ERK-VEGF/MMP-9 pathway in rat endometriosis.

SU5416 is a small molecule vascular endothelial growth factor (VEGF) receptor signal transduction inhibitor, which can block the VEGF re-ceptor autophosphorylation and inhibit receptor tyrosine kinase signal trans-duction, thereby reducing VEGF activity. However, there are few reports about the correlation of SU5416 to the occurrence and angiogenesis in endometrio-sis. In this study, we observed the effects of VEGF receptor inhibitor SU5416 on angiogenesis in endometriosis in rats. Thirty femalespecific-pathogen-free Sprague-Dawley rats were randomly divided into sham operation group (SOG), model group (MG), and SU5416 group (n=10 for each group). In the SOG, only the uterus was cut and sutured, and endometriosis models were established in the MG and SU5416 group by autologous transplantation. The SU5416 group was injected with 15 mg/kg SU5416 intraperitoneally, and the SOG and MG were intraperitoneally injected with an equal volume of normal saline for 6 weeks. The volume of ectopic lesions was lower in the SU5416 group at 42 d postoperatively thanin the MG (p<0.05). The proportion of CD31-positive cells in the endometrial tissue of the SU5416 group was lower than that of the MG (p<0.05); angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2), laminin-5γ2 (LN-5γ2) and phosphorylation of ERK (P-ERK), VEGF, matrix metalloproteinase (MMP)-2, and MMP-9 protein expressions were lower in the SU5416 groupthan in the MG (p<0.05).VEGFreceptor inhibitor SU5416 can inhibit endometrio-sis angiogenesis and reduce inflammatory response in rats, and its mechanism of action may be related to the down-regulation of the ERK-VEGF/MMP-9 path-way expression.

Luteolin photo-protects zebrafish from environmental stressor ultraviolet radiation (UVB)

ABSTRACT Ultraviolet B wavelength ray radiation (UVB) is an environmental stressor with detrimental effects to the aquatic and human systems but also enhances adverse effects when combined with several other environmental factors such as temperature and pollution. UV rays induce cellular oxidative damage and impair motility. This study aimed to examine the photo-protective activity of flavonoid luteolin against UV-B irradiation-induced oxidative stress and cellular damage using zebrafish. An in-vivo photoaging model was established using UV-B irradiation in zebrafish larvae exposed to 100 mJ/cm2. Data demonstrated that UV-B irradiation of swimming water enhanced production of ROS and superoxide anions as well as depleted total glutathione levels in zebrafish larvae. UV-B irradiation also triggered cellular damage and membrane rupture in zebra fish. Further, 100 mJ/cm2 of UV-B radiation exposure to adult-wild type zebrafish co-exposed with intraperitoneally (ip) injected luteolin upregulated the local neuroendocrine axes by activating vascular endothelial growth factor (VEGF) and elevating levels of pro-inflammatory cytokines IL-1β and TNF-α. Histologically, UV-B irradiation induced skin lesions and locomotory defects with clumping and degeneration of brain glial cells. However, luteolin effectively inhibited the excess production of reactive oxygen species (ROS) and decreased superoxide anion levels induced by UV-B irradiation. Luteolin restored the depleted glutathione levels. In addition, luteolin blocked apoptosis and lipidperoxidation. Luteolin protected adult zebrafish by downregulating the pro-inflammatory cytokine protein expression levels and diminishing VEGF activation. Luteolin also alleviated locomotory defects by inhibiting activation of microglia and inflammatory responses by preventing accumulation of glial cells and vacuolation. Data demonstrate that luteolin may protect zebrafish from UV-B-induced photodamage through DNA-protective, antioxidant and anti-inflammatory responses.

Injectable EC-BMSC hydrogel with prolonged VEGF action for enhanced angiogenesis

Tissue regeneration necessitates rapid and mature angiogenesis, while insufficient vascularization along with tissue implantation hinders the great potential applications. Endothelial cells (ECs) and bone marrow mesenchymal cells (BMSCs) are responsible for the angiogenesis in preparing bone tissue. Herein, we proposed the realization of the angiogenesis by co-culturing ECs and BMSCs within an injectable multi-crosslinked double-network (DN) hydrogel, composed of glycol chitosan (GC)/benzaldehyde-capped poly (ethylene oxide) (OHC-PEO-CHO) and calcium alginate (Alg). The hydrogel is crosslinked by dynamic interplay allowing the encapsulation, migration and proliferation of the cells. The hydrogel is capable to carry vascular endothelial growth factor (VEGF) with prolonging action within the matrix to effectively regulate the cell behavior. Co-existence of ECs and BMSCs with the VEGF within the hydrogel-based extracellular matrix (ECM) plays a key role in mediating the formation of a mature vascular structure with endothelium and pericyte. The neovascularization is closely related with the VEGF/VEGFR2/ERK signaling pathway. The finding indicates the direction toward future vascularized tissue regeneration by using a hydrogel-based scaffold with adjustable microenvironment by incorporation of functional growth factors.

MMP-13, VEGF, and Disease Activity in a Cohort of Rheumatoid Arthritis Patients

Identifying certain serum biomarkers associated with the degree of rheumatoid arthritis (RA) activity can provide us with a more accurate view of the evolution, prognosis, and future quality of life for these patients. Our aim was to analyze the presence and clinical use of matrix metalloproteinase-13 (MMP-13), along with vascular endothelial growth factor (VEGF) and well-known cytokines such as tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6) for patients with RA. We also wanted to identify the possible correlations between MMP-13 and these serological markers, as well as their relationship with disease activity indices, quality of life, and ultrasonographic evaluation. For this purpose, we analyzed serum samples of 34 RA patients and 12 controls. In order to assess serum concentrations for MMP-13, VEGF, TNF-α, and IL-6, we used the enzyme-linked immunosorbent assay (ELISA) technique. Our results concluded that higher levels of MMP-13, VEGF, TNF-α, and IL-6 were present in the serum of RA patients compared to controls, with statistical significance. We furthermore identified moderately positive correlations between VEGF, MMP-13, and disease activity indices, as well as with the ultrasound findings. We also observed that VEGF had the best accuracy (97.80%), for differentiating patients with moderate disease activity. According to the data obtained in our study, that although MMP-13, TNF-α and C-reactive protein (CRP) have the same sensitivity (55.56%), MMP-13 has a better specificity (86.67%) in the diagnosis of patients with DAS28(4v) CRP values corresponding to moderate disease activity. Thus, MMP-13 can be used as a biomarker that can differentiate patients with moderate or low disease activity. VEGF and MMP-13 can be used as additional parameters, along with TNF-α and IL-6, that can provide the clinician a better picture of the inflammatory process, disease activity, and structural damage in patients with RA. Our data can certainly constitute a start point for future research and extended studies with multicenter involvement, to support the selection of individualized and accurate therapeutic management strategies for our patients.

Exogenous ketosis elevates circulating erythropoietin and stimulates muscular angiogenesis during endurance training overload.

De novo capillarization is a primary muscular adaptation to endurance exercise training and is crucial to improving performance. Excess training load, however, impedes such beneficial adaptations, yet we recently demonstrated that such downregulation may be counteracted by ketone ester ingestion (KE) post-exercise. Therefore, we investigated whether KE could increase pro-angiogenic factors and thereby stimulate muscular angiogenesis during a 3-week endurance training-overload period involving 10 training sessions/week in healthy, male volunteers. Subjects received either 25g of a ketone ester (KE, n=9) or a control drink (CON, n=9) immediately after each training session and before sleep. In KE, but not in CON, the training intervention increased the number of capillary contacts and the capillary-to-fibre perimeter exchange index by 44% and 42%, respectively. Furthermore, KE also substantially increased vascular endothelial growth factor (VEGF) and endothelial nitric oxide synthase (eNOS) expression both at the protein and at the mRNA level. Serum erythropoietin concentration was concomitantly increased by 26%. Conversely, in CON the training intervention increased only the protein content of eNOS. These data indicate that intermittent exogenous ketosis during endurance overload training stimulates muscular angiogenesis. This likely resulted from a direct stimulation of muscle angiogenesis, which may be at least partly due to stimulation of erythropoietin secretion and elevated VEGF activity, and/or an inhibition of the suppressive effect of overload training on the normal angiogenic response to training. This study provides novel evidence to support the potential of exogenous ketosis to benefit endurance training-induced muscular adaptation. KEY POINTS: Increased capillarization is a primary muscular adaptation to endurance exercise training. However, excess training load may impede such response. We previously observed that intermittent exogenous ketosis by post-exercise and pre-sleep ketone ester ingestion (KE) counteracted physiological dysregulations induced by endurance overload training. Therefore, we investigated whether KE could increase pro-angiogenic factors thereby stimulating muscular angiogenesis during a 3-week endurance training overload period. We show that the overload training period in the presence, but not in the absence, of KE markedly increased muscle capillarization (+40%). This increase was accompanied by higher circulating erythropoietin concentration and stimulation of the pro-angiogenic factors vascular endothelial growth factor and endothelial nitric oxide synthase in skeletal muscle. Collectively, our data indicate that intermittent exogenous ketosis may evolve as a potent nutritional strategy to facilitate recovery from strenuous endurance exercise, thereby stimulating beneficial muscular adaptations.

The plant defensins PaDef and γ-thionin inhibit the endothelial cell response to VEGF

Angiogenesis is involved in wound repair and tissue maintenance but is associated with diverse diseases. Pro-angiogenic factors such as vascular endothelial growth factor (VEGF) regulate this process. Therefore, searching for treatments to inhibit or promote angiogenesis is attractive. Reports from our group showed that plant antimicrobial peptides (PAPs) PaDef from avocado and γ-thionin from habanero pepper are cytotoxic on cancer cells. However, their functions as angiogenic regulators are unknown. In this work, we evaluate the effect of PaDef and γ-thionin on the angiogenic processes of two different endothelial cell lines: bovine endothelial cells (BUVEC) and the human endothelial cell line EA.hy926. The results showed that VEGF (10 ng/mL) stimulated the BUVEC (40 ± 7 %) and EA.hy926 cell proliferation (30 ± 9 %); however, peptides (5–500 ng/mL) reverted this effect. Besides, VEGF increased the migration of BUVEC (20 ± 8 %) and EA.hy926 cells (50 ± 6 %), but both PAPs (5 ng/mL) inhibited the VEGF stimulus (100 %). Furthermore, DMOG 50 μM (an inhibitor of HIF-hydroxylase) was used in BUVEC and EA.hy926 cells to determine the effect of hypoxia on VEGF and peptide activities. The DMOG reverted the inhibitory action of both peptides (100 %), indicating that peptides act through a HIF-independent pathway. Also, the PAPs do not affect the tube formation but decrease it in EA.hy926 cells stimulated with VEGF (100 %). Additionally, docking assays showed a possible interaction between PAPs and the VEGF receptor. These results suggest that plant defensins PaDef and γ-thionin are potential angiogenic modulators of the VEGF activity on endothelial cells.

VEGF (Vascular Endothelial Growth Factor) Inhibition and Hypertension: Does Microvascular Rarefaction Play a Role?

Drugs acting by inhibition of the angiogenic action of VEGF (vascular endothelial growth factor) have become major instruments in the treatment of cancer. The downside of their favorable effects in cancer treatment is their frequent cardiovascular side effects. The most consistent finding thus far on the cardiovascular side effects of VEGF inhibitors is the high incidence of hypertension. In this short review, we discuss the evidence that hypertension occurring during VEGF inhibitor treatment is caused by microvascular rarefaction. After a review of the role of VEGF in microvascular growth and differentiation, we present evidence from studies in experimental models of hypertension as well as clinical studies on the microvascular network changes during and after VEGF inhibitor treatment.

Investigating the Role of Sterol Regulatory-Element Binding Proteins (SREBPs) in Age-Related Macular Degeneration

Background/Objective: SREBPs are transcription factors involved in lipid biogenesis and are known to play a role in angiogenesis. Vascular endothelial growth factor (VEGF) also promotes angiogenesis, with VEGF inhibitors as the predominant treatment for Age-related macular degeneration (AMD). AMD is the leading cause of permanent vision loss in the elderly population and is characterized by choroidal neovascularization (CNV). We hypothesize that VEGF can activate SREBPs in a SCAP-dependent manner.
 Methods: Human retinal microvascular endothelial cells (HRECs) were grown in 5% media and treated at passage 7. Prior to treatment, cells were all starved for 1h in 0.5% media. To estimate the changes in SREBP activation - HRECs were treated with 50ng/ml VEGF for 1, 4, and 12h or with 20 μM fatostatin, an inhibitor of SREBP activation, translocation into the nucleus, and SREBP transcription for 6h and 12h. Post treatment cells were lysed and protein was collected in RIPA buffer and semi-quantitative changes in target proteins were analyzed using immunoblotting. Statistical analysis was done by t-test, with significance if p<0.05, and sample size of n=2-3.
 Results: HRECs treated with VEGF exhibited an increasing trend for SREBP-1 and SREBP-2 in the cytoplasmic and nuclear forms at all time points. SCAP did not show a clear trend. HRECs treated with fatostatin exhibited a decreasing trend for SREBP-1 and SREBP-2 in the cytoplasmic form and nuclear SREBP-1 form at both time points. The nuclear form of SREBP-2 increased at both time points.
 Conclusion and Potential Impact: VEGF has demonstrated a role in SREBP activation, with both playing a role in angiogenesis. Fatostatin inhibition of SREBP indicated a potential antiangiogenic property. The downregulation of SREBP could provide a novel target in controlling and preventing angiogenesis in AMD. Further studies using animal models should elucidate the role of SCAP in VEGF activation of SREBPs.

Role of vascular endothelial growth factor as a critical neurotrophic factor for the survival and physiology of motoneurons.

Vascular endothelial growth factor (VEGF) was discovered by its angiogenic activity. However, during evolution, it appeared earlier as a neurotrophic factor required for the development of the nervous system in invertebrates lacking a circulatory system. We aimed at reviewing recent evidence indicating that VEGF has neuroprotective effects in neurons exposed to a variety of insults. Of particular interest is the link established between VEGF and motoneurons, especially after the design of the VEGFδ/δ mutant mice. These mice are characterized by low levels of VEGF and develop muscle weakness and motoneuron degeneration resembling amyotrophic lateral sclerosis. The administration of VEGF through several routes to animal models of amyotrophic lateral sclerosis delays motor impairment and motoneuron degeneration and increases life expectancy. There are new recent advances in the role of VEGF in the physiology of motoneurons. Our experimental aims use the extraocular (abducens) motoneurons lesioned by axotomy as a model for studying VEGF actions. Axotomized abducens motoneurons exhibit severe alterations in their discharge activity and a loss of synaptic boutons. The exogenous administration of VEGF to axotomized abducens motoneurons, either from the transected nerve or intraventricularly, fully restores the synaptic and discharge properties of abducens motoneurons, despite being axotomized. In addition, when an anti-VEGF neutralizing antibody is delivered from the muscle to intact, uninjured abducens motoneurons, these cells display alterations in their discharge pattern and a loss of synaptic boutons that resemble the state of axotomy. All these data indicate that VEGF is an essential neurotrophic factor for motoneurons.

Novel ROS-scavenging hydrogel with enhanced anti-inflammation and angiogenic properties for promoting diabetic wound healing

Accelerating angiogenesis of diabetic wounds is crucial to promoting wound healing. Currently, vascular endothelial growth factor (VEGF), an angiogenesis-related bioactive molecule, is widely used in clinic to enhance wound angiogenesis, but it faces problems of inactivation and low utilization due to harsh microenvironment. Here, we developed a novel reactive oxygen species (ROS)-scavenging hydrogel aimed to polarize macrophages toward an anti-inflammatory phenotype, inducing efficient angiogenesis in diabetic wounds. This composite hydrogel with good biosafety and mechanical properties showed sustainable release of bioactive VEGF. Importantly, it could significantly reduce ROS level and rapidly improve wound microenvironment, which ensured the activity of VEGF in vitro and in vivo and successful healing eventually. At the same time, the composite hydrogel exhibited excellent antibacterial properties. In vivo results confirmed good anti-inflammatory, stimulated vascularization and accelerated wound healing attributed to the novel ROS-scavenging hydrogel, which might serve as a promising wound dressing in diabetic wound healing.

MECHANISMS OF RESISTANCE IN THERAPY WITH ANGIOGENESIS BLOCKERS IN COLORECTAL CANCER

One of the fundamental events that determine carcinogenesis and its progression is angiogenesis mediated by the activation of the vascular endothelial growth factor (VEGF). The angiogenic cascade provides a comfortable micro-environment for the tumor, the creation of a metastatic niche and subsequent metastatic dissemination of neoplastic cells. The development of a recombinant hyperchimeric monoclonal antibody that selectively binds and inhibits the biological activity of VEGF - Bevacizumab, has led to a change in the therapeutic strategy for patients with cancer and, in particular, for patients with metastatic colorectal cancer (CRC), because it demonstrated an increase in their survival rate.

Investigation of Neutrophil Extracellular Traps as Potential Mediators in the Pathogenesis of Non-Acute Subdural Hematomas: A Pilot Study.

Non-acute subdural hematomas (NASHs) are a cause of significant morbidity and mortality, particularly with recurrences. Although recurrence is believed to involve a disordered neuroinflammatory cascade involving vascular endothelial growth factor (VEGF), this pathway has yet to be completely elucidated. Neutrophil extracellular traps (NETs) are key factors that promote inflammation/apoptosis and can be induced by VEGF. We investigated whether NETs are present in NASH membranes, quantified NET concentrations, and examined whether NET and VEGF levels are correlated in NASHs. Samples from patients undergoing NASH evacuation were collected during surgery and postoperatively at 24 and 48 h. Fluid samples and NASH membranes were analyzed for levels of VEGF, NETs, and platelet activation. NASH samples contained numerous neutrophils positive for NET formation. Myeloperoxidase-DNA complexes (a marker of NETs) remained elevated 48 h postoperatively (1.06 ± 0.22 day 0, 0.72 ± 0.23 day 1, and 0.83 ± 0.33 day 2). VEGF was also elevated in NASHs (7.08 ± 0.98 ng/mL day 0, 3.40 ± 0.68 ng/mL day 1, and 6.05 ± 1.8 ng/mL day 2). VEGF levels were significantly correlated with myeloperoxidase-DNA levels. These results show that NETs are increasing in NASH, a finding that was previously unknown. The strong correlation between NET and VEGF levels indicates that VEGF may be an important mediator of NET-related inflammation in NASH.