Collagen-binding Vascular Endothelial Growth Factor Research Articles

Collagen‑binding vascular endothelial growth factor (CBD‑VEGF) promotes liver regeneration in murine partial hepatectomy.

Liver regeneration is a complex process that needs orchestration of multiple nonparenchymal cells including sinusoid endothelial cells. Vascular endothelial growth factor (VEGF) serves a crucial role in angiogenesis and liver regeneration. However, the lack of an high‑efficiency delivery system target to the injured site reduces the local therapeutic efficacy of VEGF. In our previous study, collagen binding VEGF (CBD‑VEGF) was established by fusing collagen binding domain (CBD) into the N‑terminal of native VEGF and improved cardiac function after myocardial infraction. The present study investigated the therapeutic effect of CBD‑VEGF on liver regeneration by a mouse model of partial hepatectomy. After injection through portal vein following 2/3 hepatectomy, CBD‑VEGF was largely retained in the hepatic extracellular matrix for 48h. Furthermore, CBD‑VEGF application significantly promoted sinusoidal regeneration and remodeling in remanent liver tissue 48h after hepatectomy. In addition, CBD‑VEGF treatment significantly enhanced the proliferation of hepatocytes at 2 and 3days post‑surgery compared with native VEGF, concomitant with attenuated liver injury. In conclusion, these results demonstrated that CBD‑VEGF could be a promising therapeutic strategy for liver regeneration.

Urethral Tissue Reconstruction Using the Acellular Dermal Matrix Patch Modified with Collagen-Binding VEGF in Beagle Urethral Injury Models.

Objectives Urethral tissue reconstruction for hypospadias is challenging for urologists. In this study, bovine acellular dermal matrix (ADM) patch loading with collagen-binding vascular endothelial growth factor (CBD-VEGF) was used to repair the urethral injury in beagles. Methods The safety and effectiveness of the scaffold implantation were carefully evaluated by comparing among the urethral injury control group, ADM implantation group, and ADM modified with CBD-VEGF implantation group during 6 months. Urodynamic examination, urethral angiography, and pathological examination were performed to evaluate the recovery of urethral tissue. Results Stricture, urethral diverticulum, and increased urethral closure pressure were observed in the control group. Fistula was observed in one animal in the ADM group. By contrast, no related complications or other adverse situations were observed in animals treated with ADM patch modified with CBD-VEGF. The average urethra diameter was significantly smaller in the control animals than in scaffold implantation groups. Pathological examination revealed more distribution of proliferative blood vessels in the animals treated with ADM modified with CBD-VEGF. Conclusions Overall, ADM patches modified with CBD-VEGF demonstrated an optimized tissue repair performance in a way to increase tissue angiogenesis and maintain urethral function without inducing severe inflammation and scar formation.

Research of the anti-fibrosis factors affecting liver regeneration after partial hepatectomy for hepatic cellular carcinoma with liver cirrhosis

Hepatic cellular carcinoma is the third most common cause of cancer deaths in China. Partial hepatectomy is still the most effective treatment for hepatic cellular carcinoma. The liver is an organ with strong regenerative ability, and its regenerative mechanism is very complex. Majority of patients with hepatic cellular carcinoma are accompanied by cirrhosis, and cirrhosis is an important factor affecting the regeneration of the remaining liver after surgery. Liver regeneration is obviously impaired under this condition. However, the anti-liver fibrosis mechanisms behind these processes have not been completely elucidated, the current treatment of fibrosis is merely supportive care, and thus further definition of the anti-liver fibrosis related factors such as keratinocyte growth factor, hepatocyte growth factor, milk fat globule epidermal growth factor 8, collagen-binding vascular endothelial growth factor, ex vivo expansion of circulating CD34+ cells has far-reaching significance for improving their prognosis. This article mainly introduces some relevant factors associated with anti liver fibrosis, for later use of single factor or a combination of multifarious factors to resist liver fibrosis, to provide reference for improving the ability of remained liver regeneration after partial hepatectomy. Key words: Liver regeneration; Liver cirrhosis; Hepatic cellular carcinoma; Anti-fibrosis

“All-in-one” in vitro selection of collagen-binding vascular endothelial growth factor

To enhance the therapeutic effect of growth factors, a powerful strategy is to direct their localization to damaged sites. To treat skin wounds and myocardial infarction, we selected vascular endothelial growth factor (VEGF) carrying binding affinity to collagen. A simple conjugation of a reported collagen-binding sequence and VEGF did not increase the collagen-binding affinity, indicating that the molecular interaction between the two proteins abolished collagen binding activity. Here, we present a new molecular evolution strategy, “all-in-one” in vitro selection, in which a collagen-binding VEGF (CB-VEGF) was directly identified from a random library consisting of random and VEGF sequences. As expected, the selected CB-VEGFs exhibited high binding affinity to collagen and maintained the same growth enhancement activity for endothelial cells as unmodified VEGF in solution. Furthermore, the selected CB-VEGF enhanced angiogenesis at skin wounds and infarcted myocardium. This study demonstrates that “all-in-one” in vitro selection is a novel strategy for the design of functional proteins for regenerative medicine.

Increased vascularization promotes functional recovery in the transected spinal cord rats by implanted vascular endothelial growth factor‐targeting collagen scaffold

Spinal cord injury (SCI) is global health concern. The effective strategies for SCI are relevant to the improvement on nerve regeneration microenvironment. Vascular endothelial growth factor (VEGF) is an important cytokine for inducing angiogenesis and accelerating nerve system function recovery from injury. We proposed that VEGF could improve nerve regeneration in SCI. However, an uncontrolled delivery system target to injury site not only decreases the therapeutic efficacy but also increases the risk of tumor information. We implanted collagen scaffold (CS) targeted with a constructed protein, collagen-binding VEGF (CBD-VEGF), to bridge transected spine cord gap in a rat transected SCI model. Functional and histological examinations were conducted to assess the repair capacity of the delivery system CS/CBD-VEGF. The results indicated that the implantation of CS/CBD-VEGF into the model rats improved the survival rate and exerted beneficial effect on functional recovery. The controlled intervention improved the microenvironment, guided axon growth, and promoted neovascularization at the injury site. Therefore, the delivery system with stable binding of VEGF potentially provides a better therapeutic option for SCI. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1024-1034, 2018.

Collagen-binding vascular endothelial growth factor attenuates CCl4-induced liver fibrosis in mice.

Vascular endothelial growth factor (VEGF) serves an important role in promoting angiogenesis and tissue regeneration. However, the lack of an effective delivery system that can target this growth factor to the injured site reduces its therapeutic efficacy. Therefore, in the current study, collagen-binding VEGF was constructed by fusing a collagen-binding domain (CBD) to the N-terminal of native VEGF. The CBD-VEGF can specifically bind to collagen which is the major component of the extracellular matrix in fibrotic liver. The anti-fibrotic effects of this novel material were investigated by the carbon tetrachloride (CCl4)-induced liver fibrotic mouse model. Mice were injected with CCl4 intraperitoneally to induce liver fibrosis. CBD-VEGF was injected directly into the liver tissue of mice. The liver tissues were stained with hematoxylin and eosin for general observation or with Masson's trichrome staining for detection of collagen deposition. The hepatic stellate cell activation, blood vessel formation and hepatocyte proliferation were measured by immunohistochemical staining for α-smooth muscle actin, CD31 and Ki67 in the liver tissue. The fluorescent TUNEL assay was performed to evaluate the hepatocyte apoptosis. The present study identified that the CBD-VEGF injection could significantly promote vascularization of the liver tissue of fibrotic mice and attenuate liver fibrosis. Furthermore, hepatocyte apoptosis and hepatic stellate cell activation were attenuated by CBD-VEGF treatment. CBD-VEGF treatment could additionally promote hepatocyte regeneration in the liver tissue of fibrotic mice. Thus, it was suggested that CBD-VEGF may be used as a novel therapeutic intervention for liver fibrosis.

Mussel-inspired human gelatin nanocoating for creating biologically adhesive surfaces.

Recombinant human gelatin was conjugated with dopamine using carbodiimide as a surface modifier. This dopamine-coupled human gelatin (D-rhG) was characterized by 1H-nuclear magnetic resonance, mass spectroscopy, and circular dichroism. D-rhG-coated surface properties were analyzed by physicochemical methods. Additionally, cell attachment and growth on the modified surfaces was assessed using human umbilical endothelial cells. Binding of gelatin onto titanium was significantly enhanced by dopamine conjugation. The thickness of the D-rhG coating depended on the treatment pH; thicker layers were formed at higher pH values, with a maximum thickness of 30 nm. D-rhG enhanced the binding of collagen-binding vascular endothelial growth factor and cell adhesion as compared with gelatin alone, even at the same surface concentration. The D-rhG surface modifier enhanced substrate binding by creating an adhesive nanointerface that increased specific protein binding and cell attachment.

Therapeutic Approaches to the Regulation of Wound Angiogenesis

Re-establishment of a functional vascular network is a critical component of successful wound repair. One of the most potent pro-angiogenic agents is vascular endothelial growth factor (VEGF), which, from a basic science and pre-clinical perspective, seems ideal for the therapeutic stimulation of blood vessel growth in non-healing wounds. Current strategies to improve the dysfunctional angiogenesis that occurs in non-healing wounds are inadequate with regard to the nature and magnitude of the clinical problem. However, VEGF therapy has so far been unsuccessful in promoting healing in the clinic. More effective means of delivery to the wound, which take into account the biochemical and spatio-temporal aspects of angiogenesis, may be necessary to realize VEGF's therapeutic potential. Reviewed approaches for the regulation of wound angiogenesis include: targeting regulators of intracellular VEGF signaling, making use of collagen-binding VEGF fusion proteins for increased retention in the wound, and implantation of heterogeneous scaffold systems for spatial control of angiogenesis with simultaneous use of VEGF and its inhibitor. To maximize efficacy of therapeutic VEGF, it may be necessary to also target its intracellular inhibitory mechanisms. Immobilizing VEGF to the wound matrix may increase its bioavailability and therapeutic efficacy. Gaining spatial control of angiogenesis opens up possibilities for advanced directed therapy. The reviewed studies present innovative approaches to in vivo directed modulation of angiogenesis utilizing VEGF biology which can, if taken further and validated in human subjects, have significant impact on clinical wound care in the future.

Promotion of diabetic wound healing by collagen scaffold with collagen-binding vascular endothelial growth factor in a diabetic rat model

Studies show that VEGF can promote tissue regeneration in diabetic wounds. The aim of this study was to evaluate the effects of a new composite biomaterial, a collagen scaffold with CBD-VEGF, for wound healing in a diabetic rat model. We produced a collagen scaffold loaded with CBD-VEGF, which allowed VEGF to bind to the collagen scaffold. The diabetic rat model was constructed by injecting streptozocin (STZ) peritoneally and removing a 2 x 2.5 cm thick slice of skin from the back of the animal. Animals were randomly divided into 4 groups: blank control (BC Group, n = 24), collagen scaffold loaded with PBS (PBS Group, n = 24), collagen scaffold loaded with NAT-VEGF (NAT-VEGF Group, n = 24), and collagen scaffold loaded with CBD-VEGF (CBD-VEGF Group, n = 24). Wounds of the BC Group were covered with gauze and those of the PBS, NAT-VEGF and CBD-VEGF Groups were grafted by corresponding collagen scaffolds, respectively. Healing rates were calculated and compared among groups. Wound tissue was evaluated by histologic analysis. The CBD-VEGF group showed a higher wound healing rate, better vascularization and higher level of VEGF in the granulation tissue wound compared with NAT-VEGF and PBS groups. The collagen scaffold with CBD-VEGF promoted wound healing in a diabetic rat model, which could potentially provide better therapeutic options for the treatment of diabetic wounds.

The effect of collagen-binding vascular endothelial growth factor on the remodeling of scarred rat uterus following full-thickness injury

Serious injuries of uterine which lead to scar formation will finally result in infertility or pregnancy complications. There are few effective methods to treat such damages because of the shortage of native tissues. Vascular endothelial growth factor (VEGF) is important for the formation of new vessels and re-epithelialization of endometrium. Here we produced a collagen-binding VEGF by fusing a collagen-binding domain to the N-terminal of native VEGF. After injection into a rat scarred uterus model (partial of rat uterine horn was excised and left for scar formation) the collagen targeting VEGF promoted remodeling of the scarred uterus including the regeneration of endometrium, muscular cells, and vascularization and improved pregnancy outcomes. Thus, collagen-binding VEGF may be a pragmatic solution for the treatment of severe uterine damages.

Acceleration of diabetic wound healing by collagen-binding vascular endothelial growth factor in diabetic rat model

Aims Vascular endothelial growth factor (VEGF) is an important active protein for the induction of angiogenesis and plays an important role in the tissue regeneration of diabetic wounds. In this study, we used collagen-binding VEGF in a diabetic rat model to investigate the effects of this new method. Methods We produced a fusion protein (CBD-VEGF) consisting of VEGF and a collagen-binding domain (CBD), which allowed VEGF to bind to collagen. The diabetic rat models were made by injected streptozocin (STZ) peritoneally and removed full thickness skin on the back. All the rats were randomly divided into 3 groups: PBS group ( n = 24), NAT-VEGF group ( n = 24), and CBD-VEGF group ( n = 24). After model establishment, the dissolved drugs were evenly given on the wounds using syringe. The healing rates were calculated and compared among the groups and the tissues of the wound were taken and evaluated for histological analysis. Results The CBD-VEGF group showed better result in wound healing rate, better vascularization and higher amount of VEGF in the wound granulation tissue compared with NAT-VEGF group and control. Conclusions Topical application of CBD-VEGF can promote diabetic wound healing in rat model, which could potentially provide a better therapeutic option for diabetic wounds.

Establishment of a Functionally Active Collagen-Binding Vascular Endothelial Growth Factor Fusion Protein In Situ

Tissue regeneration requires both growth factor and extracellular matrix such as collagen, serving as a scaffold for cell growth. We established FNCBD-VEGF121, consisting of the fibronectin collagen-binding domain (FNCBD) and vascular endothelial growth factor (VEGF) 121, and investigated its properties. FNCBD-VEGF121 specifically bound to gelatin and type I, II, III, IV, and V collagen. This collagen-bound FNCBD-VEGF121 captured soluble VEGF receptor 2 (VEGFR-2)/Fc chimeric protein. Cell growth-promoting activity of FNCBD-VEGF121 was almost identical to that of VEGF121. The VEGF fusion protein significantly enhanced the expression of VEGFR-2 (71.6+/-0.8%) on endothelial progenitor cells (EPCs) derived from umbilical cord blood. Expectably, the collagen-bound VEGF fusion protein not only promoted the growth of endothelial cells (ECs) but also induced the expression of VEGFR-2 (63.7+/-0.8%) on non-adherent cells expanded from bone marrow CD34+ cells. Moreover, the VEGF fusion protein enhanced sprout formation of ECs in a matrigel model. In vivo experiments revealed that FNCBD-VEGF121 had local effects but not systemic effect on EPC mobilization. These results suggest that FNCBD-VEGF121 stably maintains an optimally high and local concentration of VEGF with collagen matrix and stimulates both ECs and EPCs in situ, supplying a vascular regeneration niche.