Influence of Recombinant Codon-Optimized Plasmid DNA Encoding VEGF and FGF2 on Co-Induction of Angiogenesis

Histamine receptor agonism differentially induces immune and reparative healing responses in biomaterial-facilitated tissue repair

Tissue repair is a highly regulated process involving immune, stromal, vascular, and parenchymal cell responses. Mediators of cellular responses at different phases of the healing process stimulate transitions through the continuum of repair. Histamine is an early mediator of healing, which, in skin, is released by resident cells (e.g., mast cells) after cutaneous injury, and acts to stimulate diverse responses in multiple cell populations. Histamine signaling is regulated by four distinct cell surface G-protein coupled receptors (HRH1-4 in humans, Hrh1-4 in mice) which initiate different downstream signaling cascades upon activation, but the specific effect of each receptor on tissue repair is poorly understood. Here, we systematically investigated the effect of selective histamine receptor agonism in laser-activated sealing and tissue repair of incisional skin wounds in immunocompetent mice. Although all four histamine receptors exhibited wound responsiveness in the epidermis, we find that activation of Hrh1, Hrh2, and Hrh4 stimulate a pro-healing immune response characterized by increased pro-resolution macrophages, reduced pro-inflammatory macrophages, and suppressed neutrophil responses. Further, activation of Hrh1 and Hrh4 stimulate angiogenesis after injury. Lastly, although Hrh1 activation resulted in enhanced epidermal epithelial-to-mesenchymal transition (EMT) in vivo and epithelialization in vitro, activation of Hrh2 suppressed both epidermal EMT and epithelialization. Activation of Hrh3, primarily found on neuronal cells, had no effect on any measure in our study. Selective histamine receptor agonism, specifically of histamine receptors Hrh-1 and 4, is a potential reparative approach to promote the efficacy of biomaterial-mediated repair of tissues, including skin.

Methacrylated hyaluronic acid/laponite photosensitive, sustained-release hydrogel loaded with bilobalide for enhancing random flap survival through mitigation of endoplasmic reticulum stress

Random flaps are extensively utilized in plastic surgery due to their flexibility compared to traditional axial vascular system arrangements and their resemblance to injured skin in color, thickness, and texture. Despite these advantages, they are susceptible to ischemia-reperfusion injuries and subsequent necrosis post-transplantation. Bilobalide (BB), a sesquiterpene compound derived from Ginkgo biloba, exhibits notable antioxidant and anti-inflammatory properties and is commonly used to treat ischemiareperfusion injuries. However, its short half-life restricts its sustained efficacy in random flaps. In this study, we synthesized a multi-crosslinked, photosensitive methacryloyl hyaluronic acid(HAMA)/laponite(Lap)/bilobalide (BB) hydrogel. This dualcrosslinked hydrogel demonstrates superior mechanical properties and biocompatibility while providing a stable release of bilobalide. In vitro experiments showed that it significantly reduces edema, promotes angiogenesis, and enhances the survival of random flaps. Further network pharmacology analysis and recovery experiments suggested that the hydrogel's beneficial effects are mediated by the regulation of endoplasmic reticulum stress and specifically identified the regulation of the PERK/TXNIP/NLRP3 signaling pathway as crucial to its anti-inflammatory effects. Therefore, this HAMA/Lap/BB hydrogel promotes the survival of random flaps in rats by alleviating endoplasmic reticulum stress, providing a novel intervention strategy for the treatment of random flaps injuries.

Biologic Brachytherapy: Genetically Modified Surgical Flap as a Therapeutic Tool-A Systematic Review of Animal Studies

Surgical flaps are rudimentary tools in reconstructive surgery, especially following extensive solid tumour resections. They cover skin and soft tissue defects but are prone to ischaemia and necrosis. Since their primary aim is reconstruction, they rarely exhibit a therapeutic activity against the treated disease. Attempts have been made to develop a new therapeutic strategy-biologic brachytherapy, which uses genetically engineered surgical flaps as a drug delivery vehicle, allowing the flap tissue to act as a "biologic pump". This systematic review summarizes the preclinical evidence on using genetically modified surgical flaps. A literature search was conducted in PubMed, EMBASE, Scopus and Web of Science. The initial literature search yielded 714 papers, and, eventually, seventy-seven studies were included in qualitative analysis. The results show that genetic enhancement of flaps has been used as a local or systemic therapy for numerous disease models. Frequently, it has been used to increase flap survival and limit ischaemia or promote flap survival in a non-ischemic context, with some studies focusing on optimizing the technique of such gene therapy. The results show that genetically modified flaps can be successfully used in a variety of contexts, but we need more studies to implement this research into specific clinical scenarios.

Galectin-3-upregulated FAK promotes angiogenesis through oral lichen planus-activated fibroblasts

BACKGROUND

The specific mechanism underlying the role of oral lichen planus-activated fibroblasts in angiogenesis remains undefined. Herein, the expression of Galectin-3 in oral lichen planus and verifying whether Galectin-3 can promote angiogenesis through oral lichen planus-activated fibroblasts has been investigated.

METHODS

The expression of Galectin-3 and CD34 in the oral lichen planus tissues (n = 30) and normal oral mucosa tissues (n = 15) was detected by immunohistochemistry. The expression of Galectin-3 in the oral lichen planus-activated fibroblasts was determined by reverse transcription-polymerase chain reaction, Western blot, and enzyme-linked immunosorbent assay. Galectin-3 overexpression lentiviral vector was constructed and transfected with oral lichen planus-activated fibroblasts. In addition, oral lichen planus-activated fibroblasts were treated with GB1107 (5 and 10 μM) to inhibit Galectin-3 expression and co-cultured with human umbilical vein vascular endothelial cells, and analyzed by Transwell and tube formation assays. The expression of VEGF and FGF2 in oral lichen planus-activated fibroblasts was detected, and the expression and phosphorylation levels of VEGFR2 and FAP in human umbilical vein vascular endothelial cells were determined.

RESULTS

Oral lichen planus subcutaneous tissues highly expressed Galectin-3, positively correlated with angiogenesis. Oral lichen planus-activated fibroblasts expressed significantly higher Galectin-3 than NFs. Oral lichen planus-activated fibroblasts overexpressing Galectin-3 enhanced the migration and tube-forming capacity of co-cultured human umbilical vein vascular endothelial cells. In oral lichen planus-activated fibroblasts, 10 μM GB1107 reduced the proliferation and migration capacity, decreased the expression of α-SMA, FAP, VEGF, and FGF2, and inhibited the tube-forming capacity and the expression of VEGFR2 phosphorylation and FAK in co-cultured human umbilical vein vascular endothelial cells.

CONCLUSIONS

The upregulation of Galectin-3 expression in oral lichen planus is associated with angiogenesis, and the oral lichen planus-activated fibroblasts promote human umbilical vein vascular endothelial cells migration and tube-forming differentiation through VEGFR2/FAP activation by Galectin-3.

Strategies to enhance the efficacy of FGF2-based therapies for skin wound healing

Basic fibroblast growth factor (FGF2 or bFGF) is critical for optimal wound healing. Experimental studies show that local application of FGF2 is a promising therapeutic approach to stimulate tissue regeneration, including for the treatment of chronic wounds that have a low healing potential or are characterised by a pathologically altered healing process. However, the problem of low efficiency of growth factors application due to their rapid loss of biological activity in the aggressive proteolytic environment of the wound remains. Therefore, ways to preserve the efficacy of FGF2 for wound treatment are being actively developed. This review considers the following strategies to improve the effectiveness of FGF2-based therapy: (1) use of vehicles/carriers for delivery and gradual release of FGF2; (2) chemical modification of FGF2 to increase the stability of the molecule; (3) use of genetic constructs encoding FGF2 for de novo synthesis of protein in the wound. In addition, this review discusses FGF2-based therapeutic strategies that are undergoing clinical trials and demonstrating the efficacy of FGF2 for skin wound healing.

A Novel Dehydrated Human Umbilical Cord Particulate Medical Device: Matrix Characterization, Performance, and Biocompatibility for the Management of Acute and Chronic Wounds

Chronic wounds present a significant socioeconomic burden forecasted to increase in prevalence and cost. Minimally manipulated human placental tissues have been increasingly employed and proven to be advantageous in the treatment of chronic wounds, showing improved clinical outcomes and cost-effectiveness. However, technological advances have been constrained by minimal manipulation and homologous use criteria. This study focuses on the characterization of a novel dehydrated human umbilical cord particulate (dHUCP) medical device, which offers a unique allogeneic technological advancement and the first human birth tissue device for wound management. Characterization analyses illustrated a complex extracellular matrix composition conserved in the dHUCP device compared to native umbilical cord, with abundant collagens and glycosaminoglycans imbibing an intricate porous scaffold. Dermal fibroblasts readily attached to the intact scaffold of the dHUCP device. Furthermore, the dHUCP device elicited a significant paracrine proliferative response in dermal fibroblasts, in contrast to fibrillar collagen, a prevalent wound device. Biocompatibility testing in a porcine full-thickness wound model showed resorption of the dHUCP device and normal granulation tissue maturation during healing. The dHUCP device is a promising advancement in wound management biomaterials, offering a unique combination of structural complexity adept for challenging wound topographies and a microenvironment supportive of tissue regeneration.

The construction of a microenvironment with the vascular network by co-culturing fibroblasts and endothelial cells

Introduction

Extracellular matrix (ECM) synthesis and deposition in fibroblasts, and vascularization via endothelial cells are essential for successful tissue regeneration. Fibroblasts can produce both ECM, physical support for maintaining homeostasis, and bioactive molecules, such as growth factors and cytokines. Endothelial cells can secrete growth factors and form vascular networks that enable the supply of nutrients and oxygen and remove metabolic products.

Methods

In this study, we focused on combining Human Periodontal Ligament Fibroblasts (HPLF) and Human Umbilical Vein Endothelial Cells (HUVEC) for tissue regeneration in clinical applications.

Results

The fibroblastic and angiogenic phenotypes were promoted in co-culture with HPLF and HUVEC at a ratio of 1:1 compared to HPLF or HUVEC mono-culture. The gene expression of ECM components and angiogenesis-related factors was also enhanced by HPLF/HUVEC co-culture. Despite an apparent increase in the expression of angiogenic factors, the levels of secreted growth factors decreased under co-culture conditions. These data suggest that ECM constructed by HPLF and HUVEC would act as a storage site for growth factors, which can later be released. Our results showed that cell-to-cell interactions between HPLF and HUVEC enhanced collagen synthesis and endothelial network formation, leading to the creation of highly vascularized constructs for periodontal tissue regeneration.

Conclusion

Successful periodontal tissue regeneration requires microenvironmental reconstruction and vascularization, which can be achieved using a co-culture system. In the present study, we found that fibroblastic and angiogenic phenotypes were enhanced by the co-culture of HPLF and HUVEC. The optimal culture conditions (1:1) could potentially accelerate tissue engineering, including ECM synthesis and EC tube formation, and these approaches can improve therapeutic efficacy after transplantation.

Overexpression of VEGF in dermal fibroblast cells accelerates the angiogenesis and wound healing function: in vitro and in vivo studies

Fibroblasts are the main cells of connective tissue and have pivotal roles in the proliferative and maturation phases of wound healing. These cells can secrete various cytokines, growth factors, and collagen. Vascular endothelial growth factor (VEGF) is a unique factor in the migration process of fibroblast cells through induces wound healing cascade components such as angiogenesis, collagen deposition, and epithelialization. This study aimed to create VEGF₁₆₅ overexpressing fibroblast cells to evaluate angiogenesis function in wound healing. In vitro, a novel recombinant expression vector, pcDNA3.1(-)-VEGF, was produced and transfected into the fibroblast cells. Following selecting fibroblast cells with hygromycin, recombinant cells were investigated in terms of VEGF expression by quantifying and qualifying methods. Mechanical, physical, and survival properties of polyurethane-cellulose acetate (PU-CA) scaffold were investigated. Finally, in vivo, the angiogenic potential was evaluated in four groups containing control, PU-CA, PU-CA with fibroblast cells, and VEGF-expressing cells on days 0, 2, 5, 12 and 15. Wound biopsies were harvested and the healing process was histopathologically evaluated on different days. qRT-PCR showed VEGF overexpression (sevenfold) in genetically-manipulated cells compared to fibroblast cells. Recombinant VEGF expression was also confirmed by western blotting. Manipulated fibroblast cells represented more angiogenesis than other groups on the second day after surgery, which was also confirmed by the antiCD31 antibody. The percentage of wound closure area on day 5 in genetically-manipulated Hu02 and Hu02 groups showed a significant reduction of wound area compared to other groups. These findings indicate that overexpression of VEGF₁₆₅ in fibroblast cells results in enhanced angiogenesis and formation of granulated tissue in the early stage of the healing process, which can show its therapeutic potential in patients with impaired wound healing and also provide functional support for gene therapy.

Alginate microspheres-collagen hydrogel, as a novel 3D culture system, enhanced skin wound healing of hUCMSCs in rats model

While stem cell transplantation has emerged as a promising approach to improving wound healing outcomes, the application of stem cells to date has been limited by the poor survival and retention of these cells once transplanted. The survival, development, and migratory activity of transplanted cells can be improved through the use of three-dimensional (3D) culture systems. Here, a novel alginate microsphere-collage hydrogel (AMS-Col gel) 3D culture system was developed and found to improve human umbilical cord mesenchymal stem cell (hUCMSC) survival, permitting their sustained release so as to promote wound healing. Through hematoxylin and eosin staining and Masson's trichrome staining, the prepared hUCMSCs-AMS-Col gel was found to exhibit wound healing activity. On day 7 following the hUCMSCs-AMS-Col gel treatment of model wounds, improved collagen fiber deposition and re-epithelialization were evident, with complete epithelial regeneration as of day 14 and near-total wound healing was evident as of day 21. This hUCMSCs-AMS-Col gel was also associated with increased VEGF and FGF2 expression. Together, these data indicate that AMS-Col gels are a promising and novel form of 3D cell culture system capable of improving hUCMSC-mediated wound healing, highlighting the potential clinical utility of this regenerative strategy.

Altered hypoxia inducible factor regulation in hereditary haemorrhagic telangiectasia

Patients with hereditary haemorrhagic telangiectasia (HHT), also known as Rendu–Osler–Weber syndrome, suffer from the consequences of abnormal vessel structures. These structures can lead to haemorrhages or shunt effects in liver, lungs and brain. This inherited and rare disease is characterized by mutations affecting the transforming growth factor-β (TGF-β)/Bone Morphogenetic Protein (BMP) pathway that results in arteriovenous malformations and studies indicate an impaired immune response. The mechanism underlying this altered immune response in HHT patients is still unknown. TGF-β interacts with hypoxia inducible factors (HIF), which both orchestrate inflammatory and angiogenic processes. Therefore, we analysed the expression of HIF and related genes in whole blood samples from HHT patients. We could show significantly decreased expression of HIF-1α on the mRNA and protein level. However, commonly known upstream regulators of HIF-1α in inflammatory responses were not affected, whereas HIF-1α target genes were significantly downregulated. There was no correlation between HIF1A or HIF2A gene expression and the severity of HHT detected. Our results represent a rare case of HIF-1α downregulation in a human disease, which underlines the relevance of HIFs in HHT. The study indicates an interaction of the known mutation in HHT and the dysregulation of HIF-1α in HHT patients, which might contribute to the clinical phenotype.

Proangiogenic Effect of 2A-Peptide Based Multicistronic Recombinant Constructs Encoding VEGF and FGF2 Growth Factors

Coronary artery disease remains one of the primary healthcare problems due to the high cost of treatment, increased number of patients, poor clinical outcomes, and lack of effective therapy. Though pharmacological and surgical treatments positively affect symptoms and arrest the disease progression, they generally exhibit a limited effect on the disease outcome. The development of alternative therapeutic approaches towards ischemic disease treatment, especially of decompensated forms, is therefore relevant. Therapeutic angiogenesis, stimulated by various cytokines, chemokines, and growth factors, provides the possibility of restoring functional blood flow in ischemic tissues, thereby ensuring the regeneration of the damaged area. In the current study, based on the clinically approved plasmid vector pVax1, multigenic constructs were developed encoding vascular endothelial growth factor (VEGF), fibroblast growth factors (FGF2), and the DsRed fluorescent protein, integrated via picornaviruses' furin-2A peptide sequences. In vitro experiments demonstrated that genetically modified cells with engineered plasmid constructs expressed the target proteins. Overexpression of VEGF and FGF2 resulted in increased levels of the recombinant proteins. Concomitantly, these did not lead to a significant shift in the general secretory profile of modified HEK293T cells. Simultaneously, the secretome of genetically modified cells showed significant stimulating effects on the formation of capillary-like structures by HUVEC (endothelial cells) in vitro. Our results revealed that when the multicistronic multigene vectors encoding 2A peptide sequences are created, transient transgene co-expression is ensured. The results obtained indicated the mutual synergistic effects of the growth factors VEGF and FGF2 on the proliferation of endothelial cells in vitro. Thus, recombinant multicistronic multigenic constructs might serve as a promising approach for establishing safe and effective systems to treat ischemic diseases.

Assessment of the Tissue Response to Modification of the Surface of Dental Implants with Carboxyethylphosphonic Acid and Basic Fibroblastic Growth Factor Immobilization (Fgf-2): An Experimental Study on Minipigs

Simple Summary

This study aimed to evaluate the efficacy of treating the surface of dental implants with carboxyethylphosphonic acid for the immobilization of FGF-2, the influence of FGF-2 on cortical bone in close contact with dental implants, new bone formation around dental implants in the presence of FGF-2 and the influence of FGF-2 on the interthread bone area of dental implants during the healing period after insertion.

Abstract

The aim of this study was to evaluate the effect of implant surface treatment with carboxyethylphosphonic acid and fibroblast growth factor 2 on the bone–implant interface during the osseointegration period in vivo using an animal model. The present research was carried out in six minipigs, in whose left tibia implants were inserted as follows: eight implants with a standard surface treatment, for the control group, and eight implants with a surface treatment of carboxyethylphosphonic acid and immobilization of FGF-2, for the test group. At 4 weeks after the insertion of the implants, the animals were sacrificed for the histomorphometric analysis of the samples. The means of the results for the implant–bone contact variable (BIC) were 46.39 ± 17.49% for the test group and 34.00 ± 9.92% for the control group; the difference was not statistically significant. For the corrected implant–bone contact variable (BICc), the mean value of the test group was 60.48 ± 18.11%, and that for the control group, 43.08 ± 10.77%; the difference was statistically significant (p-value = 0.035). The new bone formation (BV/TV) showed average results of 27.28 ± 3.88% for the test group and 26.63 ± 7.90% for the control group, meaning that the differences were not statistically significant (p-value = 0.839). Regarding the bone density at the interthread level (BAI/TA), the mean value of the test group was 32.27 ± 6.70%, and that of the control group was 32.91 ± 7.76%, with a p-value of 0.863, while for the peri-implant density (BAP/TA), the mean value of the test group was 44.96 ± 7.55%, and that for the control group was 44.80 ± 8.68%, without a significant difference between the groups. The current research only found a significant difference for the bone–implant contact at the cortical level; therefore, it could be considered that FGF-2 acts on the mineralization of bone tissue. The application of carboxyethylphosphonic acid on the surface of implants can be considered a promising alternative as a biomimetic coating for the immobilization of FGF-2. Despite no differences in the new bone formation around the implants or in the interthread or peri-implant bone density being detected, the biofunctionalization of the implant surface with FGF-2 accelerates the mineralization of the bone–implant interface at the cortical level, thereby reducing the osseointegration period.