Hydrogels to Recapture Extracellular Matrix Cues That Regulate Vascularization.

The ECM (extracellular matrix) is a 3-dimensional network that supports cellular responses and maintains structural tissue integrity in healthy and pathological conditions. The interactions between ECM and cells trigger signaling cascades that lead to phenotypic changes and structural and compositional turnover of the ECM, which in turn regulates vascular cell behavior. Hydrogel biomaterials are a powerful platform for basic and translational studies and clinical applications due to their high swelling capacity and exceptional versatility in compositions and properties. This review highlights recent developments and uses of engineered natural hydrogel platforms that mimic the ECM and present defined biochemical and mechanical cues for vascularization. Specifically, we focus on modulating vascular cell stimulation and cell-ECM/cell-cell interactions in the microvasculature that are the established biomimetic microenvironment.

Investigation of the Effects of Some Cardiovascular Drugs on Angiogenesis by Transgenic Zebrafish.

Introduction: Angiogenesis contributes to the pathophysiology of cardiovascular disease (CVD). Some cardiovascular drugs used in the treatment of CVD have an effect on the process of angiogenesis. Methods: Transgenic Tg (flk1: EGFP) zebrafish embryos were used to identify the effects of some cardiovascular drugs on angiogenesis during vertebral development in vivo. Zebrafish embryos at a one-cell stage or two-cell stage were cultured with embryo medium containing cardiovascular drugs at a final solvent concentration of 0.5% (V/V) dimethyl sulfoxide (DMSO) for 24 hours in 24-well plates. Results: We found that 6 drugs including isosorbide mononitrate, amlodipine, bisoprolol fumarate, carvedilol, irbesartan, and rosuvastatin calcium may affect angiogenesis by vascular endothelial growth factor (VEGF) signaling pathway. Conclusion: These new findings of some cardiovascular drugs should improve the treatment of cardiovascular diseases.

Fibrin-Enriched Cardiac Extracellular Matrix Hydrogel Promotes In Vitro Angiogenesis.

Angiogenesis is essential for cardiac repair after myocardial infarction. Promoting angiogenesis has been demonstrated as an effective approach for myocardial infarction treatment. Several different strategies for inducing myocardial angiogenesis have been explored, including exogenous delivery of angiogenic genes, proteins, microRNAs, cells, and extracellular vesicles. Various types of injectable hydrogels have been investigated for cardiac tissue repair. One of the most promising injectable hydrogels in cardiac regeneration is a cardiac extracellular matrix hydrogel that is derived from decellularized porcine myocardium. It can be delivered minimally invasively via transendocardial delivery. The safety and efficacy of cardiac extracellular matrix hydrogels have been shown in small and large animal myocardial infarction models as well as clinical trials. The main mechanisms underlying the therapeutic benefits of cardiac extracellular matrix hydrogels have been elucidated and involved in the modulation of the immune response, downregulation of pathways related to heart failure progression and fibrosis, upregulation of genes important for cardiac muscle contraction, and enhancing cardiomyocyte differentiation and maturation from stem cells. However, no potent capillary network formation induced by cardiac extracellular matrix hydrogels has been reported. In this study, we tested the feasibility of incorporating a fibrin matrix into cardiac extracellular matrix hydrogels to improve the angiogenic properties of the hydrogel. Our in vitro results demonstrate that fibrin-enriched cardiac extracellular matrix hydrogels can induce robust endothelial cell tube formation from human umbilical vein endothelial cells and promote the sprouting of human mesenchymal stem cell spheroids. The obtained information from this study is very critical toward the future in vivo evaluation of fibrin-enriched cardiac extracellular matrix hydrogels in promoting myocardial angiogenesis.

Beneficial Effects of Oleosomes Fused with Human Fibroblast Growth Factor 1 on Wound Healing via the Promotion of Angiogenesis.

In our previous study, human fibroblast growth factor 1 was successfully fused with oleosomes, energy-storing organelles of seeds, which are considered to be excellent "expression carriers" for substances with a convenient purification process. The present work aimed to explore the beneficial effects of oleosomes fused with human fibroblast growth factor 1 (OLAF) on wound healing. The data showed marked improvements in terms of the angiogenesis, vascular integrity, collagen and inflammation on the wound sites of rats with a full-thickness skin defect. Moreover, the positive role of OLAF in promoting angiogenesis and its possible pathways were clarified in vivo and in vitro. The results showed that the number, length and branches of the blood vessels of the chick embryo chorioallantoic membrane were markedly increased after OLAF treatment. Meanwhile, the in vitro results also revealed that 100 ng/mL OLAF exhibited a promoting effect on the proliferation, migration and tube formation of human umbilical vein endothelial cells. In addition, the potential of OLAF to improve wound angiogenesis was demonstrated to be associated with an up-regulated PI3K/Akt pathway by transcriptome sequencing analysis and the introduction of a PI3K/Akt pathway inhibitor (LY294002). These findings suggest that OLAF has many prospects in the development of drugs for wound healing.

Targeting Anti-Angiogenic VEGF165b-VEGFR1 Signaling Promotes Nitric Oxide Independent Therapeutic Angiogenesis in Preclinical Peripheral Artery Disease Models.

Nitric oxide (NO) is the critical regulator of VEGFR2-induced angiogenesis. Neither VEGF-A over-expression nor L-Arginine (NO-precursor) supplementation has been effective in helping patients with Peripheral Artery Disease (PAD) in clinical trials. One incompletely studied reason may be due to the presence of the less characterized anti-angiogenic VEGF-A (VEGF165b) isoform. We have recently shown that VEGF165b inhibits ischemic angiogenesis by blocking VEGFR1, not VEGFR2 activation. Here we wanted to determine whether VEGF165b inhibition using a monoclonal isoform-specific antibody against VEGF165b vs. control, improved perfusion recovery in preclinical PAD models that have impaired VEGFR2-NO signaling, including (1) type-2 diabetic model, (2) endothelial Nitric oxide synthase-knock out mice, and (3) Myoglobin transgenic mice that have impaired NO bioavailability. In all PAD models, VEGF165b inhibition vs. control enhanced perfusion recovery, increased microvascular density in the ischemic limb, and activated VEGFR1-STAT3 signaling. In vitro, VEGF165b inhibition vs. control enhanced a VEGFR1-dependent endothelial survival/proliferation and angiogenic capacity. These data demonstrate that VEGF165b inhibition induces VEGFR1-STAT3 activation, which does not require increased NO to induce therapeutic angiogenesis in PAD. These results may have implications for advancing therapies for patients with PAD where the VEGFR2-eNOS-NO pathway is impaired.

Engineering a Hierarchical Biphasic Gel for Subcutaneous Vascularization.

Implanted cell-containing grafts require a robust and functional vasculature to supply oxygen and nutrients, as well as clear metabolic waste products. However, it remains challenging to fabricate tunable, vascular-promoting scaffolds without incorporating additional biologics. Here, a biphasic gel consisting of a highly porous aerogel and a degradable fibrin hydrogel for inducing vascularization is presented. The highly porous (>90%) and stable aerogel is assembled from short microfibers by being dispersed in an aqueous solution that can be 3D printed into various configurations. The biphasic gel demonstrates good compression-resistance: 70.30% Young's modulus is recovered over 20 cycles of 65% compression under water. Furthermore, it is confirmed that tissue cells and blood vessels can penetrate a thick (≈3 mm) biphasic gel in the subcutaneous space of mice. Finally, the biphasic gel doubles the vascular ingrowth compared to a composite of a commercial surgical polyester felt and a fibrin hydrogel upon subcutaneous implantation in mice after 4 weeks. The design of this biphasic gel may advance the development of vascularized scaffolds.

Copper-containing titanium alloys promote angiogenesis in irradiated bone through releasing copper ions and regulating immune microenvironment.

Poor vascularization was demonstrated as a factor inhibiting bone regeneration in patients receiving radiotherapy. Various copper-containing materials have been reported to increase angiogenesis, therefore might improve bone formation. In this study, a Ti6Al4V-1.5Cu alloy was prepared using selective laser melting (SLM) technology. The immunomodulatory and pro-angiogenic effects of the Ti6Al4V-1.5Cu alloys were examined. In vitro, Ti6Al4V-1.5Cu stimulated vascular formation by restraining inflammatory factors and provoking angiogenic factors in non-irradiated and irradiated macrophages. In vivo, the angiogenic effects of the Ti6Al4V-1.5Cu alloy were confirmed using an irradiated rat femur defect model. Moreover, we found that the biological effects of the Ti6Al4V-1.5Cu alloy were partially due to the release of copper ions and associated with PI3K-Akt signaling pathway. In conclusion, this study indicated the potential of the Ti6Al4V-1.5Cu alloy to promote angiogenesis by releasing copper ions and inhibiting inflammation in normal and irradiated tissues.

Tanshinone IIA improves cardiac function via regulating miR-499-5p dependent angiogenesis in myocardial ischemic mice.

BACKGROUND/AIMS: Myocardial ischemia-reperfusion injury leads to aggravated cardiac remodeling and heart failure. After myocardial infarction (MI), angiogenesis plays a vital role in the repair and regeneration of tissue. The purpose of the current study was to determine the effect of Tanshinone IIA (Tan IIA) on angiogenesis and elucidate its related mechanism. METHODS: The C57BL/6 mice MI model was established to evaluate the therapeutic effect of Tan IIA in vivo. MicroRNA (miRNA) microarray and bioinformatics analysis were performed to determine the differential expressions of miRNAs after Tan IIA administration. Cell proliferation, migration, and angiogenesis capacity were detected by EdU, Transwell, and Tube formation assay in vitro, respectively. The relationship between miR-499-5p (miR-499) and paired phosphate and tension homolog deleted on chromosome ten (PTEN) was confirmed by using a Dual-luciferase reporter assay. RESULTS: Our results showed that Tan IIA administration improved cardiac function after MI by activating angiogenesis. Further miRNA microarray and bioinformatics analysis revealed that miR-499 was significantly down-regulated, while PTEN was remarkably upregulated after Tan IIA administration post-MI. In addition, we found that miR-499 knock-down effectively promotes cell proliferation, migration, and tube formation ability of HUVECs. Dual-luciferase reporter assay demonstrated that PTEN contains a direct binding site for miR-499-5p. CONCLUSION: Tan IIA improves cardiac function post-MI by inducing angiogenesis. In terms of the mechanism, Tan IIA promotes therapeutic angiogenesis by regulating miR-499-5p/PTEN signaling pathway.

Advances in the Pharmacological Intervention of Endothelial Progenitor Cells in the Treatment of Ischemic Stroke.

BACKGROUND: Ischemic stroke, a common central nervous system disease that seriously threatens human life and health, is characterized by rapid progress and a high disability fatality rate. Ischemic tissue can produce a large amount of vascular endothelial growth factor (VEGF) and stromal cell-derived factor 1 (SDF-1) to promote the mobilization of endothelial progenitor cells (EPCs). SUMMARY: As newly discovered stem cells, EPCs can promote angiogenesis in ischemic tissue, repair the damaged vascular endothelium, and maintain vascular homeostasis. Thus, EPCs have become a new research hotspot in this field. This review focuses on the mechanism of EPCs and the intervention of various novel drugs, including small molecules and biomolecules, which will promote the capture, proliferation, and differentiation of EPCs. Then, we explore the promotion of vascular health and the prospect of its application in the treatment of cerebral ischemic stroke (CIS). KEY MESSAGE: It is clinically significant to study the potential of new drug therapy to target EPCs. More effective cytokines, signal pathways, and other drugs should be explored in the future and their specific mechanisms determined. Research should reveal more biological functions of EPCs and achieve their efficient amplification to improve therapy against CIS stroke.

Investigations on the Wound Healing Potential of Tilapia Piscidin (TP)2-5 and TP2-6.

Wound healing is a highly orchestrated process involving many cell types, such as keratinocytes, fibroblasts and endothelial cells. This study aimed to evaluate the potential application of synthetic peptides derived from tilapia piscidin (TP)2, TP2-5 and TP2-6 in skin wound healing. The treatment of HaCaT keratinocytes with TP2-5 and TP2-6 did not cause cytotoxicity, but did enhance cell proliferation and migration, which could be attributed to the activation of epidermal growth factor receptor signaling. In CCD-966SK fibroblasts, although TP2-5 (31.25 µg/mL) and TP2-6 (125 µg/mL) showed cytotoxic effects, we observed the significant promotion of cell proliferation and migration at low concentrations. In addition, collagen I, collagen III, and keratinocyte growth factor were upregulated by the peptides. We further found that TP2-5 and TP2-6 showed pro-angiogenic properties, including the enhancement of human umbilical vein endothelial cell (HUVEC) migration and the promotion of neovascularization. In a murine model, wounds treated topically with TP2-5 and TP2-6 were reduced by day 2 post-injury and healed significantly faster than untreated wounds. Taken together, these findings demonstrate that both TP2-5 and TP2-6 have multifaceted effects when used as topical agents for accelerating wound healing.

Development of a Gene-Activated Scaffold Incorporating Multifunctional Cell-Penetrating Peptides for pSDF-1α Delivery for Enhanced Angiogenesis in Tissue Engineering Applications.

Non-viral gene delivery has become a popular approach in tissue engineering, as it permits the transient delivery of a therapeutic gene, in order to stimulate tissue repair. However, the efficacy of non-viral delivery vectors remains an issue. Our lab has created gene-activated scaffolds by incorporating various non-viral delivery vectors, including the glycosaminoglycan-binding enhanced transduction (GET) peptide into collagen-based scaffolds with proven osteogenic potential. A modification to the GET peptide (FLR) by substitution of arginine residues with histidine (FLH) has been designed to enhance plasmid DNA (pDNA) delivery. In this study, we complexed pDNA with combinations of FLR and FLH peptides, termed GET* nanoparticles. We sought to enhance our gene-activated scaffold platform by incorporating GET* nanoparticles into collagen-nanohydroxyapatite scaffolds with proven osteogenic capacity. GET* N/P 8 was shown to be the most effective formulation for delivery to MSCs in 2D. Furthermore, GET* N/P 8 nanoparticles incorporated into collagen-nanohydroxyapatite (coll-nHA) scaffolds at a 1:1 ratio of collagen:nanohydroxyapatite was shown to be the optimal gene-activated scaffold. pDNA encoding stromal-derived factor 1α (pSDF-1α), an angiogenic chemokine which plays a role in BMP mediated differentiation of MSCs, was then delivered to MSCs using our optimised gene-activated scaffold platform, with the aim of significantly increasing angiogenesis as an important precursor to bone repair. The GET* N/P 8 coll-nHA scaffolds successfully delivered pSDF-1α to MSCs, resulting in a significant, sustained increase in SDF-1α protein production and an enhanced angiogenic effect, a key precursor in the early stages of bone repair.

The Effects of αvß3 Integrin Blockage in Breast Tumor and Endothelial Cells under Hypoxia In Vitro.

Breast cancer is characterized by a hypoxic microenvironment inside the tumor mass, contributing to cell metastatic behavior. Hypoxia induces the expression of hypoxia-inducible factor (HIF-1α), a transcription factor for genes involved in angiogenesis and metastatic behavior, including the vascular endothelial growth factor (VEGF), matrix metalloproteinases (MMPs), and integrins. Integrin receptors play a key role in cell adhesion and migration, being considered targets for metastasis prevention. We investigated the migratory behavior of hypoxia-cultured triple-negative breast cancer cells (TNBC) and endothelial cells (HUVEC) upon αvß3 integrin blocking with DisBa-01, an RGD disintegrin with high affinity to this integrin. Boyden chamber, HUVEC transmigration, and wound healing assays in the presence of DisBa-01 were performed in hypoxic conditions. DisBa-01 produced similar effects in the two oxygen conditions in the Boyden chamber and transmigration assays. In the wound healing assay, hypoxia abolished DisBa-01's inhibitory effect on cell motility and decreased the MMP-9 activity of conditioned media. These results indicate that αvß3 integrin function in cell motility depends on the assay and oxygen levels, and higher inhibitor concentrations may be necessary to achieve the same inhibitory effect as in normoxia. These versatile responses add more complexity to the role of the αvß3 integrin during tumor progression.

Towards Induction of Angiogenesis in Dental Pulp Stem Cells Using Chitosan-Based Hydrogels Releasing Basic Fibroblast Growth Factor.

INTRODUCTION: Chitosan is a natural biopolymer that attracted enormous attention in biomedical fields. The main components of regenerative endodontic procedures (REPs), as well as tissue engineering, are scaffolds, stem cells, and growth factors. As one of the basic factors in the REPs is maintaining vascularization, this study was aimed at developing basic fibroblast growth factor- (bFGF-) loaded scaffolds and investigating their effects on the angiogenic induction in human dental pulp stem cells (hDPSCs). METHODS: Poly (ε-caprolactone) (PCL)/chitosan- (CS-) based highly porous scaffold (PCL/CS) was prepared and evaluated by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analyses. The adhesion and survival potency of seeded cells were assessed by SEM and MTT assays, respectively. The amount of angiogenic markers was investigated in gene and protein levels by real-time PCR and western blotting assays, respectively. RESULTS: Based on our findings, the SEM and FTIR tests confirmed the appropriate structure of synthesized scaffolds. Besides, the adhesion and survival rate of cells and the levels of VEGFR-2, Tie2, and Angiopoietin-1 genes were increased significantly in the PCL/CS/bFGF group. Also, the western blotting results showed the upregulation of these markers at protein levels, which were considerably higher at the PCL/CS/bFGF group (P < 0.05). CONCLUSIONS: On a more general note, this study demonstrates that the bFGF-loaded PCL/CS scaffolds have the potential to promote angiogenesis of hDPSCs, which could provide vitality of dentin-pulp complex as the initial required factor for regenerative endodontic procedures.

Milk exosomes-mediated miR-31-5p delivery accelerates diabetic wound healing through promoting angiogenesis.

The refractory diabetic wound has remained a worldwide challenge as one of the major health problems. The impaired angiogenesis phase during diabetic wound healing partly contributes to the pathological process. MicroRNA (miRNA) is an essential regulator of gene expression in crucial biological processes and is a promising nucleic acid drug in therapeutic fields of the diabetic wound. However, miRNA therapies have limitations due to lacking an effective delivery system. In the present study, we found a significant reduction of miR-31-5p expression in the full-thickness wounds of diabetic mice compared to normal mice. Further, miR-31-5p has been proven to promote the proliferation, migration, and angiogenesis of endothelial cells. Thus, we conceived the idea of exogenously supplementing miR-31-5p mimics to treat the diabetic wound. We used milk-derived exosomes as a novel system for miR-31-5p delivery and successfully encapsulated miR-31-5p mimics into milk exosomes through electroporation. Then, we proved that the miR-31-5p loaded in exosomes achieved higher cell uptake and was able to resist degradation. Moreover, our miRNA-exosomal formulation demonstrated dramatically improved endothelial cell functions in vitro, together with the promotion of angiogenesis and enhanced diabetic wound healing in vivo. Collectively, our data showed the feasibility of milk exosomes as a scalable, biocompatible, and cost-effective delivery system to enhance the bioavailability and efficacy of miRNAs.

Nanofiber/hydrogel core-shell scaffolds with three-dimensional multilayer patterned structure for accelerating diabetic wound healing.

Impaired angiogenesis is one of the predominant reasons for non-healing diabetic wounds. Herein, a nanofiber/hydrogel core-shell scaffold with three-dimensional (3D) multilayer patterned structure (3D-PT-P/GM) was introduced for promoting diabetic wound healing with improved angiogenesis. The results showed that the 3D-PT-P/GM scaffolds possessed multilayered structure with interlayer spacing of about 15-80 µm, and the hexagonal micropatterned structures were uniformly distributed on the surface of each layer. The nanofibers in the scaffold exhibited distinct core-shell structures with Gelatin methacryloyl (GelMA) hydrogel as the shell and Poly (D, L-lactic acid) (PDLLA) as the core. The results showed that the porosity, water retention time and water vapor permeability of the 3D-PT-P/GM scaffolds increased to 1.6 times, 21 times, and 1.9 times than that of the two-dimensional (2D) PDLLA nanofibrous scaffolds, respectively. The in vitro studies showed that the 3D-PT-P/GM scaffolds could significantly promote cell adhesion, proliferation, infiltration and migration throughout the scaffolds, and the expression of cellular communication protein-related genes, as well as angiogenesis-related genes in the same group, was remarkably upregulated. The in vivo results further demonstrated that the 3D-PT-P/GM scaffolds could not only effectively absorb exudate and provide a moist environment for the wound sites, but also significantly promote the formation of a 3D network of capillaries. As a result, the healing of diabetic wounds was accelerated with enhanced angiogenesis, granulation tissue formation, and collagen deposition. These results indicate that nanofiber/hydrogel core-shell scaffolds with 3D multilayer patterned structures could provide a new strategy for facilitating chronic wound healing.

Biomimetic porous scaffolds containing decellularized small intestinal submucosa and Sr2+/Fe3+co-doped hydroxyapatite accelerate angiogenesis/osteogenesis for bone regeneration.

The design of bone scaffolds is predominately aimed to well reproduce the natural bony environment by imitating the architecture/composition of host bone. Such biomimetic biomaterials are gaining increasing attention and acknowledged quite promising for bone tissue engineering. Herein, novel biomimetic bone scaffolds containing decellularized small intestinal submucosa matrix (SIS-ECM) and Sr2+/Fe3+co-doped hydroxyapatite (SrFeHA) are fabricated for the first time by the sophisticated self-assembled mineralization procedure, followed by cross-linking and lyophilization post-treatments. The results indicate the constructed SIS/SrFeHA scaffolds are characterized by highly porous structures, rough microsurface and improved mechanical strength, as well as efficient releasing of bioactive Sr2+/Fe3+and ECM components. These favorable physico-chemical properties endow SIS/SrFeHA scaffolds with an architectural/componential biomimetic bony environment which appears to be highly beneficial for inducing angiogenesis/osteogenesis bothin vitroandin vivo. In particular, the cellular functionality and bioactivity of endotheliocytes/osteoblasts are significantly enhanced by SIS/SrFeHA scaffolds, and the cranial defects model further verifies the potent ability of SIS/SrFeHA to acceleratein vivovascularization and bone regeneration following implantation. In this view these results highlight the considerable angiogenesis/osteogenesis potential of biomimetic porous SIS/SrFeHA scaffolds for inducing bone regeneration and thus may afford a new promising alternative for bone tissue engineering.

Possibility of adiponectin use to improve islet transplantation outcomes.

Although islet transplantation (ITx) is a promising therapy for severe diabetes mellitus, further advancements are necessary. Adiponectin, an adipokine that regulates lipid and glucose metabolism, exerts favorable effects on islets, such as reinforcement of the insulin-releasing function. This study evaluated the possibility of adiponectin use to improve ITx outcomes. We treated mouse islets with 10 µg/mL recombinant mouse adiponectin by overnight culture and then assessed the insulin-releasing, angiogenic, and adhesion functions of the islets. Furthermore, 80 syngeneic islet equivalents with or without adiponectin treatment were transplanted into the renal subcapsular space of diabetic mice. In in vitro assessment, released insulin at high glucose stimulation, insulin content, and expressions of vascular endothelial growth factor and integrin ß1 were improved in adiponectin-treated islets. Furthermore, adiponectin treatment improved the therapeutic effect of ITx on blood glucose levels and promoted angiogenesis of the transplanted islets. However, the therapeutic effect was not pronounced in glucose tolerance test results. In conclusion, adiponectin treatment had preferable effects in the insulin-releasing, angiogenic, and adhesion functions of islets and contributed to the improvement of ITx. The future use of adiponectin treatment in clinical settings to improve ITx outcomes should be investigated.

Transdermal Delivery of a Hydrogen Sulphide Donor, ADT-OH Using Aqueous Gel Formulations for the Treatment of Impaired Vascular Function: an Ex Vivo Study.

PURPOSE: Hydrogen sulphide (H2S) is an important signalling molecule involved in the regulation of several physiological and pathophysiological processes. The objective of this study was to investigate the feasibility of transdermal delivery of ADT-OH, a H2S donor, by investigating the transdermal flux of aqueous gels loaded with penetration enhancers or liposomes. Furthermore, we explored the ability of permeated ADT-OH to promote angiogenesis and mitochondrial bioenergetics in HUVEC cells. METHODS: Aqueous hypromellose gels (5% w/v) were prepared with up to 10% v/v propylene glycol (PG) or deformable liposomes with 0.025% w/w ADT-OH. ADT-OH permeation from formulations across excised murine skin into PBS was quantified over 24 h using HPLC-UV detection. Media was collected and applied to HUVEC cells to evidence ADT-OH functionality following permeation. Tube formation assays were performed as indicative of angiogenesis and mitochondrial oxygen consumption was evaluated using a Seahorse XF24. RESULTS: Increasing the loading of PG caused an increase in ADT-OH permeation rate across skin and a decrease in dermal drug retention whereas liposomal gels produced a slow-release profile. Treatment of HUVEC's using conditioned media collected from the ADT-OH loaded permeation studies enhanced tube formation and the basal oxygen consumption rates after 30 min of treatment. CONCLUSIONS: These findings demonstrate that transdermal delivery of ADT-OH may provide a promising approach in the treatment of impaired vascular function. Gels prepared with 10% v/v PG have the potential for use in conditions requiring rapid H2S release whereas liposomal loaded gels for treatment requiring sustained H2S release.

Loading of erythropoietin on biphasic calcium phosphate bioceramics promotes osteogenesis and angiogenesis by regulating EphB4/EphrinB2 molecules.

Improving osteogenesis and angiogenesis using different cells and drugs is critical in the field of bone tissue engineering. Recent research has found that erythropoietin (EPO) plays an important role in both osteogenesis and angiogenesis. In this study, we grafted polydopamine and EPO onto the surface of biphasic calcium phosphate. The characterization and release property of the modified bioceramics were assessed. Cell proliferation, expression of osteoblastic and endothelial markers, and EphB4/EphrinB2 molecules were investigated while employing co-cultures of two different cells [rat vein endothelial cells (VECs) and rat bone marrow mesenchymal stromal cells (BMSCs)]. The modified bioceramics were finally implanted into the SD rats' femurs and followed by investigating the bone defect repair efficacy and the expression of EphB4/EphrinB2 molecules in vivo. The results indicated that the modified bioceramics could control the release of EPO continuously. The osteogenesis and angiogenesis were improved along with the increased expression of EphB4/EphrinB2 molecules. The expression of EphB4/EphrinB2 molecules was also significantly increased in vivo and the bone defect was repaired effectively. Overall, our findings demonstrated that EPO loading on biphasic calcium phosphate bioceramics could promote both osteogenesis and angiogenesis. The results suggest that EphB4/EphrinB2 may be crucial in the process. Graphical abstract.

Buxue Yimu Pills improve angiogenesis and blood flow in experimental zebrafish and rat models.

ETHNOPHARMACOLOGICAL RELEVANCE: Buxue Yimu Pills (BYP) is a well-known traditional Chinese medicine prescription which is clinical used in gynecology and obstetrics, and is documented to exhibit therapeutic potential to defective angiogenesis and impaired blood flow. AIM OF THE STUDY: This study aimed to investigate the effects and biological mechanisms of BYP in improvement of defective angiogenesis and impaired blood flow which represent major health issues associated with various diseases including postpartum or abortion complications. MATERIALS AND METHODS: In this study, VEGFR tyrosine kinase inhibitor II (VRI) was used to establish blood vessel loss model in Tg(fli-1a:EGFP) zebrafish embryos. Blood vessel loss was calculated, and quantitative real-time PCR (qRT-PCR) assay was performed to detect gene expression. Mifepristone and misoprostol were applied to construct a medical-induced incomplete abortion rats model. Whole blood viscosity indexes, hemorheology and coagulation function of the rats were investigated. Immunohistochemistry analysis was used for evaluation of the uterine tissues. RESULTS: BYP treatment significantly promoted angiogenesis as evidenced by the restoration of VRI-induced blood vessel loss in zebrafish embryos. BYP treatment effectively reversed VRI-induced down-regulation of the VEGFRs (Kdr, Kdrl and Flt1). Furthermore, BYP administration significantly suppressed the increase of whole blood viscosity indexes, and remarkably shortened the levels of prothrombin time and activated partial thromboplastin time in the medical-induced incomplete abortion rats, indicating the improvement of hemorheology and coagulation function. Immunohistochemistry analysis suggested that BYP administration increased the expression level of VEGFR2 in uterus tissues of the rats. CONCLUSION: BYP exhibits therapeutic effects in promoting angiogenesis and blood circulation, and mitigating blood stasis, supporting its clinical application for postpartum or abortion complications.