scholarly journals Poly-ε-Caprolactone/Fibrin-Alginate Scaffold: A New Pro-Angiogenic Composite Biomaterial for the Treatment of Bone Defects

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3399
Author(s):  
Jiongyu Ren ◽  
Nupur Kohli ◽  
Vaibhav Sharma ◽  
Taleen Shakouri ◽  
Zalike Keskin-Erdogan ◽  
...  

We hypothesized that a composite of 3D porous melt-electrowritten poly-ɛ-caprolactone (PCL) coated throughout with a porous and slowly biodegradable fibrin/alginate (FA) matrix would accelerate bone repair due to its angiogenic potential. Scanning electron microscopy showed that the open pore structure of the FA matrix was maintained in the PCL/FA composites. Fourier transform infrared spectroscopy and differential scanning calorimetry showed complete coverage of the PCL fibres by FA, and the PCL/FA crystallinity was decreased compared with PCL. In vitro cell work with osteoprogenitor cells showed that they preferentially bound to the FA component and proliferated on all scaffolds over 28 days. A chorioallantoic membrane assay showed more blood vessel infiltration into FA and PCL/FA compared with PCL, and a significantly higher number of bifurcation points for PCL/FA compared with both FA and PCL. Implantation into a rat cranial defect model followed by microcomputed tomography, histology, and immunohistochemistry after 4- and 12-weeks post operation showed fast early bone formation at week 4, with significantly higher bone formation for FA and PCL/FA compared with PCL. However, this phenomenon was not extrapolated to week 12. Therefore, for long-term bone regeneration, tuning of FA degradation to ensure syncing with new bone formation is likely necessary.

2020 ◽  
Vol 21 (5) ◽  
pp. 1802 ◽  
Author(s):  
Andrey Ratushnyy ◽  
Mariia Ezdakova ◽  
Ludmila Buravkova

Nowadays, paracrine regulation is considered as a major tool of mesenchymal stem cell (MSC) involvement in tissue repair and renewal in adults. Aging results in alteration of tissue homeostasis including neovascularization. In this study, we examined the influence of replicative senescence on the angiogenic potential of adipose-derived MSCs (ASCs). Angiogenic activity of conditioned medium (CM) from senescent and “young” ASCs was evaluated in chorioallantoic membrane (CAM) assay in ovo using Japanese quail embryos. Also, the formation of capillary-like tubes by human umbilical vein endothelial cells (HUVECs) in 3D basement membrane matrix “Matrigel” and HUVEC migration capacity were analyzed. Multiplex, dot-blot and gene expression analysis were performed to characterize transcription and production of about 100 angiogenesis-associated proteins. The results point to decreased angiogenic potential of senescent ASC secretome in ovo. A number of angiogenesis-associated proteins demonstrated elevation in CM after long-term cultivation. Meanwhile, VEGF (key positive regulator of angiogenesis) did not change transcription level and concentration in CM. Increasing both pro- (FGF-2, uPA, IL-6, IL-8 etc.) and antiangiogenic (IL-4, IP-10, PF4, Activin A, DPPIV etc.) factors was observed. Some proangiogenic genes were downregulated (IGF1, MMP1, TGFB3, PDGFRB, PGF). Senescence-associated secretory phenotype (SASP) modifications after long-term cultivation lead to attenuation of angiogenic potential of ASC.


Author(s):  
Samuel C. Uzoechi ◽  
Goddy C. Okoye ◽  
Kennedy O. Ejeta ◽  
Benjamin I. Nkem ◽  
Gideon I. Ndubuka

Calcium phosphate is a widely used material as coating for metallic implants. This research describes a biomimetic coating techniques based on deposition of calcium phosphate films on a Ti6Al4V plates that was used to study the effect of strontium additive on the behavior of hMSCs. In this study, strontium additive was homogenously deposited onto calcium phosphate films on a Ti6AlV plates by using a biomimetic techniques. Strontium affected composition and morphology of calcium phosphate deposited on a Ti6Al4V plates to a varying degree, according to concentration of solutions used. The effect of strontium additive on proliferation and differentiation of hMSCs depended on the solution and concentration tested. In general, all individual three coatings showed decreased hMSCs proliferation. Strontium additive demonstrated a significant increase in differentiation into osteogenic lineage when compared with the control and calcium phosphate films without strontium additive. However, no cytotoxic effect of strontium additive in the concentrations tested was detected. The Fourier transform infrared spectra showed that this new coating closely resembles bone mineral. The techniques illustrated in this study mimics bone mineral containing strontium additive, making it constructive for studying basic processes of in vitro bone formation. The results showed in this study can be used for changing bone graft substitutes by addition of strontium additive on implants in order to affect their performance in bone repair and regeneration. Also, the system can aid rapid bone formation around the implant, reducing therewith the patient’s recovery time after surgery.


2021 ◽  
Vol 12 ◽  
Author(s):  
Yarong Wang ◽  
Zekun Gan ◽  
Haibin Lu ◽  
Ziyi Liu ◽  
Peng Shang ◽  
...  

Nowadays, the bone osseointegration in different environments is comparable, but the mechanism is unclear. This study aimed to investigate the osseointegration of different bioactive titanium surfaces under normoxic or high-altitude hypoxic environments. Titanium implants were subjected to one of two surface treatments: (1) sanding, blasting, and acid etching to obtain a rough surface, or (2) extensive polishing to obtain a smooth surface. Changes in the morphology, proliferation, and protein expression of osteoblasts on the rough and smooth surfaces were examined, and bone formation was studied through western blotting and animal-based experiments. Our findings found that a hypoxic environment and rough titanium implant surface promoted the osteogenic differentiation of osteoblasts and activated the JAK1/STAT1/HIF-1α pathway in vitro. The animal study revealed that following implant insertion in tibia of rabbit, bone repair at high altitudes was slower than that at low altitudes (i.e., in plains) after 2weeks; however, bone formation did not differ significantly after 4weeks. The results of our study showed that: (1) The altitude hypoxia environment would affect the early osseointegration of titanium implants while titanium implants with rough surfaces can mitigate the effects of this hypoxic environment on osseointegration, (2) the mechanism may be related to the activation of JAK1/STAT1/HIF-1α pathway, and (3) our results suggest the osteogenesis of titanium implants, such as oral implants, is closely related to the oxygen environment. Clinical doctors, especially dentists, should pay attention to the influence of hypoxia on early osseointegration in patients with high altitude. For example, it is better to choose an implant system with rough implant surface in the oral cavity of patients with tooth loss at high altitude.


2020 ◽  
Author(s):  
Nafiseh Baheiraei ◽  
Hossein Eyni ◽  
Bita bakhshi ◽  
Raziyeh Najafloo

Abstract Background Bioactive glasses (BGs) have attracted added attention in the structure of the scaffolds for bone repair applications. Different metal ions could be doped in BGs to induce specific biological responses. Among these ions, strontium (Sr) is considered as an effective and safe doping element with promising effects on bone formation and regeneration. Methods In this experiment, we evaluated the antibacterial activities of the gelatin-BG (Gel-BG) and Gel-BG/Sr scaffolds in vitro. The osteogenic properties of the prepared scaffolds were also assessed in rabbit calvarial bone defects for 12 weeks. Alizarin Red, Hematoxylin & Eosin (H&E) and Masson’s Trichrome staining were performed to assess bone regeneration and the obtained results were compared with those without Sr. Also, histomorphometric data were obtained to evaluate the new bone, residual graft, and connective tissue. Results Both scaffolds showed in vivo bone formation during 12 weeks with the newly formed bone area in Gel-BG/Sr scaffold was higher than that in Gel-BG scaffolds after the whole period. Based on the histological results, Gel-BG/Sr exhibited acceleration of early-stage bone formation in vivo. The results of antibacterial investigation showed that although both Gel-BG/Sr and Gel-BG effectively inhibited the growth of Escherichia coli (E. coli) but, only Gel-BG/Sr structure could lead to a 3 log reduction in Staphylococcus aureus (S. aureus). Conclusions: Our results confirmed that Sr doped BG is a favorable candidate for bone tissue engineering with superior antibacterial activity and bone regeneration capacity compared with similar counterparts having no Sr ion.


Blood ◽  
1999 ◽  
Vol 93 (8) ◽  
pp. 2627-2636 ◽  
Author(s):  
Domenico Ribatti ◽  
Marco Presta ◽  
Angelo Vacca ◽  
Roberto Ria ◽  
Roberta Giuliani ◽  
...  

Abstract Hematopoietic and endothelial cell lineages share common progenitors. Accordingly, cytokines formerly thought to be specific for the hematopoietic system have been shown to affect several functions in endothelial cells, including angiogenesis. In this study, we investigated the angiogenic potential of erythropoietin (Epo), the main hormone regulating proliferation, differentiation, and survival of erythroid cells. Epo receptors (EpoRs) have been identified in the human EA.hy926 endothelial cell line by Western blot analysis. Also, recombinant human Epo (rHuEpo) stimulates Janus Kinase-2 (JAK-2) phosphorylation, cell proliferation, and matrix metalloproteinase-2 (MMP-2) production in EA.hy926 cells and significantly enhances their differentiation into vascular structures when seeded on Matrigel. In vivo, rHuEpo induces a potent angiogenic response in the chick embryo chorioallantoic membrane (CAM). Accordingly, endothelial cells of the CAM vasculature express EpoRs, as shown by immunostaining with an anti-EpoR antibody. The angiogenic response of CAM blood vessels to rHuEpo was comparable to that elicited by the prototypic angiogenic cytokine basic fibroblast growth factor (FGF2), it occurred in the absence of a significant mononuclear cell infiltrate, and it was not mimicked by endothelin-1 (ET-1) treatment. Taken together, these data demonstrate the ability of Epo to interact directly with endothelial cells and to elicit an angiogenic response in vitro and in vivo and thus act as a bona fide direct angiogenic factor.


2020 ◽  
Author(s):  
Nafiseh Baheiraei ◽  
Hossein Eyni ◽  
Bita bakhshi ◽  
Raziyeh Najafloo

Abstract Background: Bioactive glasses (BGs) have attracted added attention in the structure of the scaffolds for bone repair applications. Different metal ions could be doped in BGs to induce specific biological responses. Among these ions, strontium (Sr) is considered as an effective and safe doping element with promising effects on bone formation and regeneration.Methods: In this experiment, we evaluated the antibacterial activities of the gelatin-BG (Gel-BG) and Gel-BG/Sr scaffolds in vitro. The osteogenic properties of the prepared scaffolds were also assessed in rabbit calvarial bone defects for 12 weeks. Alizarin Red, Hematoxylin & Eosin (H&E) and Masson’s Trichrome staining were performed to assess bone regeneration and the obtained results were compared with those without Sr. Also, histomorphometric data were obtained to evaluate the new bone, residual graft, and connective tissue.Results: Both scaffolds showed in vivo bone formation during 12 weeks with the newly formed bone area in Gel-BG/Sr scaffold was higher than that in Gel-BG scaffolds after the whole period. Based on the histological results, Gel-BG/Sr exhibited acceleration of early-stage bone formation in vivo. The results of antibacterial investigation showed that although both Gel-BG/Sr and Gel-BG effectively inhibited the growth of Escherichia coli (E. coli) but, only Gel-BG/Sr structure could lead to a 3 log reduction in Staphylococcus aureus (S. aureus). Conclusions: Our results confirmed that Sr doped BG is a favorable candidate for bone tissue engineering with superior antibacterial activity and bone regeneration capacity compared with similar counterparts having no Sr ion.


Author(s):  
Siddharth Shanbhag ◽  
Ahmad Rashad ◽  
Ellen Helgeland Nymark ◽  
Salwa Suliman ◽  
Catharina de Lange Davies ◽  
...  

Cell coculture strategies can promote angiogenesis within tissue engineering constructs. This study aimed to test the angiogenic potential of human umbilical vein endothelial cells (HUVEC) cocultured with gingiva-derived progenitor cells (GPC) as spheroids in a xeno-free environment. Human platelet lysate (HPL) was used as a cell culture supplement and as a hydrogel matrix (HPLG) for spheroid encapsulation. HUVEC and HUVEC + GPC (1:1 or 5:1) spheroids were encapsulated in various HPLG formulations. Angiogenesis was assessed via in vitro sprouting and in vivo chick chorioallantoic membrane (CAM) assays. HUVEC revealed characteristic in vitro sprouting in HPL/HPLG and this was significantly enhanced in cocultures with GPC (p < 0.05). A trend for greater sprouting was observed in 5:1 vs 1:1 HUVEC + GPC spheroids and in certain HPLG formulations (p > 0.05). Both HUVEC and HUVEC + GPC spheroids in HPLG revealed abundant and comparable neoangiogenesis in the CAM assay (p > 0.05). Spheroid coculture of HUVEC + GPC in HPLG represents a promising strategy to promote angiogenesis.


2018 ◽  
Vol 45 (5) ◽  
pp. 1927-1939 ◽  
Author(s):  
Fei Xiao ◽  
Chuandong Wang ◽  
Chenglong Wang ◽  
Yuan Gao ◽  
Xiaoling Zhang ◽  
...  

Background/Aims: During bone repair and remodeling, osteogenesis is coupled with angiogenesis. Bone morphogenetic protein (BMP) antagonists are important modulators of BMP signaling and bone homeostasis. Several investigations have demonstrated that one ‘BMP antagonist’, BMP-binding endothelial cell precursor-derived regulator (BMPER), participates in the regulation of BMP signaling. In this study, we examined the role of BMPER in the osteogenesis-angiogenesis coupling process. Methods: Human bone mesenchymal stem cells (hBMSCs) and human umbilical vein endothelial cells (HUVECs) were used in this experiment. After overexpressing or silencing BMPER with lentiviruses or siRNA, hBMSCs were stimulated by BMP-2, and osteogenic differentiation activity was detected by alkaline phosphatase and alizarin red staining. VEGF and endostatin release were assessed by ELISA. HUVEC migration was detected by the cell scratch test and transwell migration assay, and in vitro angiogenesis was determined by the tube formation assay. Bone formation was assessed using in vivo femoral monocortical defect and ectopic bone formation models. Results: BMP-2 upregulated BMPER expression. Overexpression of BMPER remarkably enhanced BMP-2-induced osteogenic differentiation, while suppression of BMPER effectively inhibited this process both in vitro and in vivo. In addition, overexpression of BMPER promoted BMP-2-induced VEGF expression in vitro and vascularization in the ectopic bone formation model. Conclusion: BMPER functions as a positive regulator of the osteogenesis-angiogenesis coupling process in hBMSCs, suggesting a novel therapeutic role of BMPER in the regenerative capacity of bone repair.


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