In vitro evaluation of Panax notoginseng Rg1 released from collagen/chitosan-gelatin microsphere scaffolds for angiogenesis

Succinate-induced macrophage polarization and RBP4 secretion promote vascular sprouting in ocular neovascularization

Pathological neovascularization is a pivotal biological process in wet age-related macular degeneration (AMD), retinopathy of prematurity (ROP) and proliferative diabetic retinopathy (PDR), in which macrophages (Mφs) play a key role. Tip cell specialization is critical in angiogenesis; however, its interconnection with the surrounding immune environment remains unclear. Succinate is an intermediate in the tricarboxylic acid (TCA) cycle and was significantly elevated in patients with wet AMD by metabolomics. Advanced experiments revealed that SUCNR1 expression in Mφ and M2 polarization was detected in abnormal vessels of choroidal neovascularization (CNV) and oxygen-induced retinopathy (OIR) models. Succinate-induced M2 polarization via SUCNR1, which facilitated vascular endothelial cell (EC) migration, invasion, and tubulation, thus promoting angiogenesis in pathological neovascularization. Furthermore, evidence indicated that succinate triggered the release of RBP4 from Mφs into the surroundings to regulate endothelial sprouting and pathological angiogenesis via VEGFR2, a marker of tip cell formation. In conclusion, our results suggest that succinate represents a novel class of vasculature-inducing factors that modulate Mφ polarization and the RBP4/VEGFR2 pathway to induce pathological angiogenic signaling through tip cell specialization.

Dual gene-activated dermal scaffolds regulate angiogenesis and wound healing by mediating the coexpression of VEGF and angiopoietin-1

The vascularization of dermal substitutes is a key challenge in efforts to heal deep skin defects. In this study, dual gene-activated dermal scaffolds (DGADSs-1) were fabricated by loading nanocomposite particles of polyethylenimine (PEI)/multiple plasmid DNAs (pDNAs) encoding vascular endothelial growth factor and angiopoietin-1 at a ratio of 1:1. In a similar manner, DGADSs-2 were loaded with a chimeric plasmid encoding both VEGF and Ang-1. In vitro studies showed that both types of DGADSs released PEI/pDNA nanoparticles in a sustained manner; they demonstrated effective transfection ability, leading to upregulated expression of VEGF and Ang-1. Furthermore, both types of DGADSs promoted fibroblast proliferation and blood vessel formation, although DGADSs-1 showed a more obvious promotion effect. A rat full-thickness skin defect model showed that split-thickness skin transplanted using a one-step method could achieve full survival at the 12th day after surgery in both DGADSs-1 and DGADSs-2 groups, and the vascularization time of dermal substitutes was significantly shortened. Compared with the other three groups of scaffolds, the DGADSs-1 group had significantly greater cell infiltration, collagen deposition, neovascularization, and vascular maturation, all of which promoted wound healing. Thus, compared with single-gene-activated dermal scaffolds, DGADSs show greater potential for enhancing angiogenesis. DGADSs with different loading modes also exhibited differences in terms of angiogenesis; the effect of loading two genes (DGADSs-1) was better than the effect of loading a chimeric gene (DGADSs-2). In summary, DGADSs, which continuously upregulate VEGF and Ang-1 expression, offer a new functional tissue-engineered dermal substitute with the ability to activate vascularization.

A review on polysaccharides mediated electrospun nanofibers for diabetic wound healing: Their current status with regulatory perspective

The current treatment strategies for diabetic wound care provide only moderate degree of effectiveness; hence new and improved therapeutic techniques are in great demand. Diabetic wound healing is a complex physiological process that involves synchronisation of various biological events such as haemostasis, inflammation, and remodelling. Nanomaterials like polymeric nanofibers (NFs) offer a promising approach for the treatment of diabetic wounds and have emerged as viable options for wound management. Electrospinning is a powerful and cost-effective method to fabricate versatile NFs with a wide array of raw materials for different biological applications. The electrospun NFs have unique advantages in the development of wound dressings due to their high specific surface area and porosity. The electrospun NFs possess a unique porous structure and biological function similar to the natural extracellular matrix (ECM), and are known to accelerate wound healing. Compared to traditional dressings, the electrospun NFs are more effective in healing wounds owing to their distinct characteristics, good surface functionalisation, better biocompatibility and biodegradability. This review provides a comprehensive overview of the electrospinning procedure and its operating principle, with special emphasis on the role of electrospun NFs in the treatment of diabetic wounds. This review discusses the present techniques applied in the fabrication of NF dressings, and highlights the future prospects of electrospun NFs in medicinal applications.

Panax notoginseng saponins improves healing of high glucose-induced wound through the GSK-3β/β-catenin pathway

Chronic non-healing wounds are one of the most common complications of diabetes mellitus and results in a huge physical and mental burden for patients. Panax notoginseng saponins (PNS) have a wide range of applications in anti-apoptosis, anti-oxidation, and promoting blood circulation. Our study aimed to explore whether PNS could improve diabetic wound healing. High-glucose (HG, 30 Mm) were used to incubated human umbilical vein endothelial cells (HUVECs) to simulate the hyperglycemia environment in vivo, and 200 μg/ml (optimum harmless concentration screened) PNS was added into HG-incubated HUVECs to investigate the protective effect of PNS on the cells. Compared with control, high glucose treatment significantly suppressed HUVEC proliferation, invasion, migration, angiogenesis, malondialdehyde (MDA) production and nitric oxide (NO) release, promoted cell apoptosis, and deactivated the GSK-3β/β-catenin/VEGF pathway. PNS treatment could largely rescue the effects of HG on cell dysfunction and improve the deactivation of GSK-3β/β-catenin/VEGF pathway. ICG-001, a small molecular β-catenin inhibitor that can selectively antagonize β-catenin mediated transcriptional activity, could eliminate the protective effects of PNS on cell dysfunction and activation of GSK-3β/β-catenin/VEGF pathway. Moreover, Furthermore, a diabetic model (50 mg/kg streptozotocin induced) with back skin wound was established in rats, and the wounds were administrated with petrolatum, gelatin/Bletilla striata gelatin (GT/BSGT), or GT/BSGT plus PNS. We found that PNS signally facilitated wound healing and matrix remodeling in vivo. In conclusion, our study verified that PNS improved wound healing in hyperglycemic rats via promoting endothelial cell proliferation, invasion, migration, angiogenesis, suppressing cell apoptosis and oxidative damage, and activating the GSK-3β/β-catenin pathway.

An Update on the Potential Application of Herbal Medicine in Promoting Angiogenesis

Angiogenesis, the formation of new capillaries from pre-existing vascular networks, plays an important role in many physiological and pathological processes. The use of pro-angiogenic agents has been proposed as an attractive approach for promoting wound healing and treating vascular insufficiency-related problems, such as ischemic heart disease and stroke, which are the leading causes of death worldwide. Traditional herbal medicine has a long history; however, there is still a need for more in-depth studies and evidence-based confirmation from controlled and validated trials. Many in vitro and in vivo studies have reported that herbal medicines and their bioactive ingredients exert pro-angiogenic activity. The most frequently studied pro-angiogenic phytochemicals include ginsenosides from Panax notoginseng, astragalosides and calycosin from Radix Astragali, salvianolic acid B from Salvia miltiorrhiza, paeoniflorin from Radix Paeoniae, ilexsaponin A1 from Ilex pubescens, ferulic acid from Angelica sinensis, and puerarin from Radix puerariae. This review summarizes the progress in research on these phytochemicals, particularly those related to pro-angiogenic mechanisms and applications in ischemic diseases, tissue repair, and wound healing. In addition, an outline of their limitations and challenges during drug development is presented.

Evaluation of the wound healing properties of South African medicinal plants using zebrafish and in vitro bioassays

ETHNOPHARMACOLOGICAL RELEVANCE

In South Africa, medicinal plants have a history of traditional use, with many species used for treating wounds. The scientific basis of such uses remains largely unexplored.

AIM OF THE STUDY

To screen South African plants used ethnomedicinally for wound healing based on their pro-angiogenic and wound healing activity, using transgenic zebrafish larvae and cell culture assays.

MATERIALS AND METHODS

South African medicinal plants used for wound healing were chosen according to literature. Dried plant material was extracted using six solvents of varying polarities. Pro-angiogenesis was assessed in vivo by observing morphological changes in sub-intestinal vessels after crude extract treatment of transgenic zebrafish larvae with vasculature-specific expression of a green fluorescent protein. Subsequently, the in vitro anti-inflammatory, fibroblast proliferation and collagen production effects of the plant extracts that were active in the zebrafish angiogenesis assay were investigated using murine macrophage (RAW 264.7) and human fibroblast (MRHF) cell lines.

RESULTS

Fourteen plants were extracted using six different solvents to yield 84 extracts and the non-toxic (n=72) were initially screened for pro-angiogenic activity in the zebrafish assay. Of these plant species, extracts of Lobostemon fruticosus, Scabiosa columbaria and Cotyledon orbiculata exhibited good activity in a concentration-dependent manner. All active extracts showed negligible in vitro toxicity using the MTT assay. Lobostemon fruticosus and Scabiosa columbaria extracts showed noteworthy anti-inflammatory activity in RAW 264.7 macrophages. The acetone extract of Lobostemon fruticosus stimulated the most collagen production at 122% above control values using the MRHF cell line, while all four of the selected extracts significantly stimulated cellular proliferation in vitro in the MRHF cell line.

CONCLUSIONS

The screening of the selected plant species provided valuable preliminary information validating the use of some of the plants in traditional medicine used for wound healing in South Africa. This study is the first to discover through an evidence-based pharmacology approach the wound healing properties of such plant species using the zebrafish as an in vivo model.

Nanomaterials for the delivery of bioactive factors to enhance angiogenesis of dermal substitutes during wound healing

Dermal substitutes provide a template for dermal regeneration and reconstruction. They constitutes an ideal clinical treatment for deep skin defects. However, rapid vascularization remains as a major hurdle to the development and application of dermal substitutes. Several bioactive factors play an important regulatory role in the process of angiogenesis and an understanding of the mechanism of achieving their effective delivery and sustained function is vital. Nanomaterials have great potential for tissue engineering. Effective delivery of bioactive factors (including growth factors, peptides and nucleic acids) by nanomaterials is of increasing research interest. This paper discusses the process of dermal substitute angiogenesis and the roles of related bioactive factors in this process. The application of nanomaterials for the delivery of bioactive factors to enhance angiogenesis and accelerate wound healing is also reviewed. We focus on new systems and approaches for delivering bioactive factors for enhancing angiogenesis in dermal substitutes.

Progress of gelatin-based microspheres (GMSs) as delivery vehicles of drug and cell

Gelatin has various attractive features as biomedical materials, for instance, biocompatibility, low immunogenicity, biodegradability, and ease of manipulation. In recent years, various gelatin-based microspheres (GMSs) have been fabricated with innovative technologies to serve as sustained delivery vehicles of drugs and genetic materials as well as beneficial bacteria. Moreover, GMSs have exhibited promising potentials to act as both cell carriers and 3D scaffold components in tissue engineering and regenerative medicine, which not only exhibit excellent injectability but also could be integrated into a macroscale construct with the laden cells. Herein, we aim to thoroughly summarize the recent progress in the preparations and biomedical applications of GMSs and then to point out the research direction in future. First, various methods for the fabrication of GMSs will be described. Second, the recent use of GMSs in tumor embolization and in the delivery of cells, drugs, and genetic material as well as bacteria will be presented. Finally, several key factors that may enhance the improvement of GMSs were suggested as delivery vehicles.

Co-electrospun nano-/microfibrous composite scaffolds with structural and chemical gradients for bone tissue engineering

Recent trends in scaffold design for tissue engineering have focused on providing structural, mechanical and chemical cues for guiding cell behaviors. In this study, we presented a structural/compositional gradient nano-/microfibrous mesh by co-electrospinning, using silk fibroin-poly(ε-caprolactone) (SF-PCL) nanofibers and PCL microfibers. The pore size, porosity, and physical property of the gradient meshes were qualified. Cell proliferation of mouse osteoblast-like MC3T3-E1 cells was carried out to estimate the effect of structural and compositional gradients on biocompatibility. Furthermore, the 2-D mesh was rolled up and the compressive property of 3-D cylinder was investigated. The results suggested that the rolled-up gradient cylinder scaffold exhibited higher osteogenic differentiation compared to the pristine nanofibrous cylinder sample. By incorporating Chinese medicine ginsenoside Rg1, sustained release was achieved in composite meshes. Rg1-containing nanofibrous meshes and Rg1 gradient cylinders enhanced the cell proliferation of human umbilical vein endothelial cells (HUVECs). The developed fibrous scaffold may provide structural, compositional, and chemical gradients for bone regeneration. BRIEFS: Structural and chemical gradient fibrous scaffold fabricated by co-electrospinning.

Preparation and Evaluation of Sustained Release Platelet-Rich Plasma-Loaded Gelatin Microspheres Using an Emulsion Method

The management and treatment of chronic wounds or acute wounds remain a major challenge in modern medicine. The application of autologous platelet-rich plasma (PRP) has become a promising adjuvant therapy to promote wound healing. PRP is derived from centrifuged whole blood to extract concentrated platelets, and a large amount of cytokines and growth factors are released upon activation. These bioactive molecules can enhance angiogenesis and tissue regeneration. Herein, PRP-loaded gelatin microspheres were prepared by the emulsion cross-linking method. Scanning electron microscopy results showed that the prepared microspheres are completely spherical, with an average particle size of 15.95 ± 3.79 μm and having a uniform particle size. Among them, the surface of a single microsphere is smooth and has a microporous structure, which may be the main channel for drug diffusion. Results of drug release measurements show that the prepared microspheres can slowly release the vascular endothelial growth factor for more than 7 days. In vitro cell experiments show that the prepared microspheres can promote proliferation and migration of L929 mouse fibroblast cells. In summary, the prepared PRP-loaded gelatin microspheres with high and long-term activity can provide experimental and theoretical knowledge for the development of the clinical long-acting injectable formulations.

Traditional Chinese medicine formulas, extracts, and compounds promote angiogenesis

Ischemic diseases, such as ischemic heart diseases and ischemic stroke, are the leading cause of death worldwide. Angiogenic therapy is a wide-ranging approach to fighting ischemic diseases. However, compared with anti-angiogenesis therapy for tumors, less attention has been paid to therapeutic angiogenesis. Recently, Traditional Chinese medicine (TCM) has garnered increasing interest for its definite curative effect and low toxicity. A growing number of studies have reported that TCM formulas, extracts, and compounds from herbal medicines exert pro-angiogenic activity, which has been confirmed in a few clinical trials. For comprehensive analysis of relevant literature, global and local databases including PubMed, Web of Science, and China National Knowledge Infrastructure were searched using keywords such as "angiogenesis," "neovascularization," "traditional Chinese medicine," "formula," "extract," and "compound." Articles were chosen that are closely and directly related to pro-angiogenesis. This review summarizes the pro-angiogenic activity and the mechanism of TCM formulas, extracts, and compounds; it delivers an in-depth understanding of the relationship between TCM and pro-angiogenesis and will provide new ideas for clinical practice.

The effects of ginsenosides on platelet aggregation and vascular intima in the treatment of cardiovascular diseases: From molecular mechanisms to clinical applications

Thrombosis initiated by abnormal platelet aggregation is a pivotal pathological event that precedes most cases of cardiovascular diseases (CVD). Recently, growing evidence indicates that platelet could be a potential target for CVD prevention. However, as the conventional antithrombotic management strategy, applications of current antiplatelet agents are somewhat limited by their various side effects, such as bleeding risk and drug resistance. Hence, efforts have been made to search for agents as complementary therapies. Ginsenoside, the principal active component extracted from Panax ginseng, has gained much attention for its regulations on multiple crucial events of platelet aggregation. From structural characteristics to clinical applications, this review anatomized the intrinsic structure-function relationship of antiplatelet potency of ginsenosides, and the involved signal pathways were specifically summarized. Additionally, the emphasis was placed on clinical studies that investigate the antithrombotic efficacy of ginsenosides in the treatment of CVD. Further, a broad overview of approaches for improving the bioavailability of ginsenosides was concluded. Limitations and prospects of current studies were also discussed. This study may provide some new insights into the systematic understanding of ginsenosides in CVD treatment and lay a foundation for future research.

Development of 20(S)-Protopanaxadiol-Loaded SNEDDS Preconcentrate Using Comprehensive Phase Diagram for the Enhanced Dissolution and Oral Bioavailability

In this study, we aimed to develop a 20(S)-protopanaxadiol (PPD)-loaded self-nanoemulsifying drug delivery system (SNEDDS) preconcentrate (PSP) using comprehensive ternary phase diagrams for enhanced solubility, physical stability, dissolution, and bioavailability. Capmul MCM C8 and Capryol 90 were selected as the oil phase owing to the high solubility of PPD in these vehicles (>15%, w/w). Novel comprehensive ternary phase diagrams composed of selected oil, surfactant, and PPD were constructed, and the solubility of PPD and particle size of vehicle was indicated on them for the effective determination of PSP. PSPs were confirmed via particle size distribution, physical stability, and scanning electron microscope (SEM) with the dispersion of water. The optimized PSP (CAPRYOL90/Kolliphor EL/PPD = 54/36/10, weight%) obtained from the six possible comprehensive ternary phase diagrams showed a uniform nanoemulsion with the particle size of 125.07 ± 12.56 nm without any PPD precipitation. The PSP showed a dissolution rate of 94.69 ± 2.51% in 60 min at pH 1.2, whereas raw PPD showed negligible dissolution. In oral pharmacokinetic studies, the PSP group showed significantly higher C_max and AUC_inf values (by 1.94- and 1.81-fold, respectively) than the raw PPD group (p < 0.05). In conclusion, the PSP formulation with outstanding solubilization, dissolution, and in-vivo oral bioavailability could be suggested using effective and comprehensive ternary phase diagrams.

Natural composite dressings based on collagen, gelatin and plant bioactive compounds for wound healing: A review

Skin wound dressings are commonly used to stimulate and enhance skin tissue repair. Even if wounds seem easy to repair for clinicians and to replicate in an in vitro set-up for scientists, chronic wounds remain currently an open challenge in skin tissue engineering for patients with complementary diseases. The seemingly simple process of skin healing hides a heterogenous sequence of events, specific timing, and high level of organization and coordination among the involved cell types. Taken together, all these aspects make wound healing a unique process, but we are not yet able to completely repair the chronic wounds or to reproduce them in vitro with high fidelity. This review highlights the main characteristics and properties of a natural polymer, which is widely used as biomaterial, namely collagen and of its denatured form, gelatin. Available wound dressings based on collagen/gelatin and proposed variants loaded with bioactive compounds derived from plants are presented. Applications of these composite biomaterials are discussed with emphasis on skin wound healing. A perspective on current issues is given in the light of future research. The emerging technologies support the development of innovative dressings based exclusively on natural constituents, either polymeric or bioactive compounds.

Phytochemistry, pharmacology, and clinical use of Panax notoginseng flowers buds

Panax notoginseng is a well-known traditional Chinese medicine, and dried flower buds of P. notoginseng (FBP) have also been used as a medicine or tea for a long time. The pharmacological effects of FBP include antihypertensive, anticancer, hepatoprotective, and cardiovascular protective effects. The compounds in FBP include saponins, flavonoids, volatile oils, and polysaccharides. The total saponins are the principal bioactive components. In modern applications, FBP is used to treat hypertension and tinnitus. There have been many studies on FBP and its effects in recent years, and it has attracted much attention in the medical field. This review summarizes the chemical components, pharmacological action, and clinical uses of FBP comprehensively to provide the references of deeper studies.

Micro-/nano-sized delivery systems of ginsenosides for improved systemic bioavailability

Ginsenosides, dammarane-type triterpene saponins obtained from ginseng, have been used as a natural medicine for many years in the Orient due to their various pharmacological activities. However, the therapeutic potential of ginsenosides has been largely limited by the low bioavailability of the natural products caused mainly by low aqueous solubility, poor biomembrane permeability, instability in the gastrointestinal tract, and extensive metabolism in the body. To enhance the bioavailability of ginsenosides, diverse micro-/nano-sized delivery systems such as emulsions, polymeric particles, and vesicular systems have been investigated. The delivery systems improved the bioavailability of ginsenosides by enhancing solubility, permeability, and stability of the natural products. This mini-review aims to provide comprehensive information on the micro-/nano-sized delivery systems for increasing the bioavailability of ginsenosides, which may be helpful for designing better delivery systems to maximize the versatile therapeutic potential of ginsenosides.

Endophytic fungi harbored in Panax notoginseng: diversity and potential as biological control agents against host plant pathogens of root-rot disease

Background

Endophytic fungi play an important role in balancing the ecosystem and boosting host growth. In the present study, we investigated the endophytic fungal diversity of healthy Panax notoginseng and evaluated its potential antimicrobial activity against five major phytopathogens causing root-rot of P. notoginseng.

Methods

A culture-dependent technique, combining morphological and molecular methods, was used to analyze endophytic fungal diversity. A double-layer agar technique was used to challenge the phytopathogens of P. notoginseng.

Results

A total of 89 fungi were obtained from the roots, stems, leaves, and seeds of P. notoginseng, and 41 isolates representing different morphotypes were selected for taxonomic characterization. The fungal isolates belonged to Ascomycota (96.6%) and Zygomycota (3.4%). All isolates were classified to 23 genera and an unknown taxon belonging to Sordariomycetes. The number of isolates obtained from different tissues ranged from 12 to 42 for leaves and roots, respectively. The selected endophytic fungal isolates were challenged by the root-rot pathogens Alternaria panax, Fusarium oxysporum, Fusarium solani, Phoma herbarum, and Mycocentrospora acerina. Twenty-six of the 41 isolates (63.4%) exhibited activity against at least one of the pathogens tested.

Conclusion

Our results suggested that P. notoginseng harbors diversified endophytic fungi that would provide a basis for the identification of new bioactive compounds, and for effective biocontrol of notoginseng root rot.

Bone morphogenetic protein-2 and vascular endothelial growth factor in bone tissue regeneration: new insight and perspectives

The study of bone tissue regeneration in orthopaedic diseases has stimulated great interest among bone tissue engineering specialists and orthopaedic surgeons. Combinations of biomaterials, growth factors and stem cells for repairing bone have been much studied and researched, yet remain a challenge for both scientists and clinicians pursuing regenerative medicine. The purpose of this review was to elucidate the role of sequential release of bone morphogenetic protein-2 and vascular endothelial growth factor in producing better outcomes in the field of bone tissue regeneration.