Research Status of Endothelialization of Poly （ε-caprolactone） Small-Caliber Vascular Graft Implanted in Animals / 医用生物力学

The most serious problem facing the implantation of vascular graft in the body is the formation of blood clots. In order to solve this problem, various attempts have been made by the scientific community for many years. However, endothelialization is the fundamental method to solve thrombosis and keep vascular graft open for a long time. Poly （ε-caprolactone） (PCL) has the advantages of biodegradability, low cost and good mechanical properties. In recent years, it has been widely used as tissue engineering scaffolds, drug deliverys and so on. This article mainly reviews the endothelialization of small-caliber vascular graft based on PCL after implanted in different animal models, as well as the endothelialization of the same animal model but under different implantation conditions, and trying to find the reasons why small-caliber vascular grafts are still not ideal in clinical applications at different angles such as the different animal models and the different way about endothelialization, and provide references for future animal model selection.

Histocompatibility of poly(L-lactide-co-ε-caprolactone)/cross-linked polyvinylpyrrolidone ureteral stent grafted into the rat bladder / 中国组织工程研究

BACKGROUND: With the development of tissue engineering, materials science, and biomechanics, developing new biodegradable ureteral stent has become an issue of concern. The ureteral stent with poly(L-lactide-co-ε-caprolactone)/crosslinked polypyrrolidone was prepared. OBJECTIVE: To explore the histocompatibility of the ureteral stent grafted into the bladder of Sprague-Dawley rats. METHODS: Sixty male Sprague-Dawley rats (provided by Laboratory Animal Center of Sichuan Academy of Traditional Chinese Medicine) were randomly divided into four groups, each group containing 15 rats. The sham operation group was directly sutured after opening a small incision on the outside of the bladder, and no material was implanted. The other three groups were implanted with polyurethane ureteral stent (control group), poly(L-lactide-co-ε-caprolactone)/8% cross-linked polyvinylpyrrolidone ureter stent (experiment group 1), poly(L-lactide ε- caprolactone)/5% cross-linked polyvinylpyrrolidone ureteral stent (experiment group 2) after opening a small incision on the outer side of the bladder, followed by suturing the incision. At 4, 8, and 16 weeks after operation, the local anatomy of the bladder was observed. The histocompatibility of the materials in each group was observed by hematoxylin-eosin staining. The study was approved by the Ethical Committee of Laboratory Animal Analysis and Testing Center of West China School of Public Health, Sichuan University. RESULTS AND CONCLUSION: (1) Gross observation: At 4, 8 and 16 weeks postoperatively, different degrees of chronic inflammation reaction occurred in the control group and experimental group 1. In the experiment group 2, chronic inflammatory reaction appeared at 4 weeks postoperatively. The stone formation rate in the control group and experimental group 1 was significantly higher than that in the sham operation group (P 0. 05). The calculus formation rate in the experimental group 2 was significantly higher than that in the sham operation group only at 4 weeks postoperatively, and had no significant difference at other time points (P > 0. 05). (2) Pathological observation: Different degrees of foreign body in the outer membrane, inflammatory reaction and diffuse hyperplasia of the mucosa were found in the control group, experimental groups 1 and 2 at different time points postoperatively. There was no significant difference in the rate of diffuse hyperplasia of the mucosa at different time points postoperatively among groups (P > 0. 05), but higher than that in the sham operation group (P < 0. 05). (3) These results indicate that the calculus formation rate and bladder histological reaction of poly(L-lactide-co-ε-caprolactone)/cross-linked polyvinylpyrrolidone ureter stent are comparable with those of commercial ureteral stents, especially the addition of 5% cross-linked polyvinylpyrrolidone has better histocompatibility.

Effect of silk fibroin on degradation and in vivo biocompatibility of poly (L-lactic-co-ε-caprolactone) electronspun nanofibrous scaffolds / 第二军医大学学报

Objective To investigate the effect of silk fibroin (SF) on degradation and biocompatibility of poly (L-lactic acid-co-e-caprolactone) (P[LLA-CL]) in vivo. Methods The scaffolds of P(LLA-CL) (w/w=1:1) blended with 25% of SF (SF/P[LLA-CL]) and P(LLA-CL) were prepared by electrospinning. Both kinds of scaffolds were subcutaneously implanted in 45 6-month-old rats for up to 6 months to evaluate their degradation and biocompatibility characteristics. Results Pathological sections showed P(LLA-CL) scaffold become swollen and began to separate into different layers after 3 months, and then become broken after 6 months; while SF/P (LLA-CL) scaffold largely maintained its structure after 6 months. Immunohistochemical staining showed a large number of macrophages on the surface and in P(LLA-CL) scaffolds 1 month after implantation, and they could still be found 3 months after implantation, accompanied by foreign body giant cells; while no obvious macrophages or foreign body giant cells were found in SF/P(LLA-CL) scaffolds at different time points. Examination of inflammatory gene expression showed that TNF-α and IL-10 expression in P(LLA-CL) scaffolds was significantly higher than that in SF/P(LLA-CL) scaffolds 1 week after implantation (P<0. 05), the same was also true for TNF-α, IL-1β and IL-10 expression 1 month after implantation (P<0. 05), for TNF-α and IL-10 expression 2 months after implantation (P<0. 05), for TGF-β expression 3 months after implantation (P<0. 05%, and for IL-1β and TGF-β expression 6 months after implantation (P<0. 05%). Conclusion SF incorporation can delay degradation, reduce inflammation, and improve the biocompatibility of P(LLA-CL) scaffolds, which may provide reference for scaffold design in tissue engineering.

Effect of Zebularine loaded MePEG-PCL nanoparticles on viability, attachment of in vitro cultured lens epithelial cells / 国际眼科杂志(Guoji Yanke Zazhi)

Abstract?AlM: To investigate the effect of zebularine ( Zeb ) loaded Poly ( ethylene glycol ) - block - poly ( ε -caprolactone) methyl ether ( MePEG-PCL) nanoparticles ( NPs) on the viability, attachment, and apoptosis of in vitro cultured lens epithelial cells ( LECs) .?METHODS: In vitro cultured infant human lens tissue HLE B-3 immortalized cells were distributed randomly divided into six groups. Each group was administered with free Zeb 50μmol/L ( ZebF1 group ) , 100μmol/L ( ZebF2 group) , Zeb -loaded MePEG-PCL NPs 50μmol/L ( ZebNP1 group) , Zeb -loaded MePEG-PCL NPs 100μmol/L ( ZebNP2 group) , MePEG-PCL empty NPs( NPs group) or blank medium (group C) respectively. A tetrazolium dye assay ( MTT) test and modified MTT test were performed to determine cell viability and cell attachment. DNA ladder was used to detect the cell apoptosis.?RESULTS: Determined by MTT colorimetric method:Cell proliferation rate of LECs were suppressed by all Zeb administration groups in a concentration-time dependent manner (P ZebNP1>ZebF2 (P<0. 05).?CONCLUSlON: Zeb loaded MePEG-PCL NPs had better effect on suppressing the viability and attachment of in vitro cultured LECs than the free Zeb groups , as well as enhancing the apoptosis.

Formulation and evaluation of nanoparticles containing artemisinin HCL.

The present study deals with the formulation and evaluation of Artemisinin HCl nanoparticles. Artemisinin is a sesquiterpene lactone chemical extract from Artemisia annua (sweet wormwood), is poorly soluble in water and a fast-acting blood schizonticide effective in treating the acute attack of malaria (including chloroquine – resistant and celebral malaria). Artemisinin are effective against multi-resistant strains of P. falciparum. The purpose of the present work is to minimize the dosing frequency, taste masking and toxicity and to improve the therapeutic efficacy by formulating Artemisinin HCl nanoparticles. Artemisinin HCl nanoparticles were formulated by solvent evaporation method using polymer poly(ε-caprolactone) with five different formulations. Nanoparticles were characterized by determining its particle size, polydispersity index, drug entrapment efficiency, particle morphological character and drug release. The particle size ranged between 100nm to 240nm. Drug entrapment efficacy was > 99%. The in-vitro release of nanoparticles were carried out which exhibited a sustained release of Artemisinin HCl from nanoparticles up to 24hrs. The results showed that nanoparticles can be a promising drug delivery system for sustained release of Artemisinin HCl.

Chemical constituents from roots of Breynia fruticosa / 中草药

Objective: To study the chemical constituents from the roots of Breynia fruticosa. Methods: The compounds were isolated by comprehensive column chromatography, and the structures were elucidated by spectral methods. Results: Thirteen compounds were isolated and elucidated, including four triterpenoids, friedelin (1), friedelinol (2), lupenone (3), and glochidiol (4); three steroids, including β-sitosterol (5), stigmastane-3β, 6β-diol (6), and β-sitosterylglucoside-6'-octadecanoate (7); two cerebrosides, including 1-O-β-D-glucopyranosyl-(2S, 3R, 4E, 8Z)-2-[(2-hydroxyoctadecanoyl) amido]-4, 8-octadecadiene-1, 3-diol (8) and 1-O-β-D-glucopyranosyl-(2S, 3S, 4R, 8Z)-2-[(2R)-2-hydroxypentacosanoylamino]-8-octadecene-1, 3, 4-triol (9); and four other compounds, including (-)-epicatchin (10), ε-caprolactone (11), aviculin (12), and vanillin (13). Conclusion: Compounds 3, 4, 6-9, and 11 are isolated from the plant of Breynia J. R. et G. Forst. nom. cons. for the first time, and compound 11 is isolated from the natural product for the first time.

Paclitaxel loaded poly(ε-caprolactone)/poloxamer 188 blend microspheres and in vivo evaluation of its antitumor activity / 国际生物医学工程杂志

Objective To prepare paclitaxel-loaded poly(ε-caprolactone)(PCL)/pluronic F68(F68)blend microspheres as a controlled release system. Methods Paclitaxel-loaded PCL/F68 blend microspheres were prepared by the oil-in water(O/W)emulsion/solvent evaporation method. Characterization of the microspheres followed to examine the particle size, the drug encapsulation efficiency, the surface morphology, in vitro release behavior and DSC analysis. In vivo antitumor activity of paclitaxel-loaded PCL/F68 blend microspheres was evaluated in mice bearing with hepatoma H22 cells ascites tumor. Results The results showed that the porous structure can be formed in the surface of PCL/F68 blend microspheres. Faster and controlled release of paclitaxel from PCL/F68 blend microspheres was achieved in comparison with the PCL microspheres. In animal tests, paclitaxel-loaded PCL/F68 blend microspheres showed the potent antitumor activity against hepatoma H22 cells in ascites tumor model. Conclusion The paclitaxel loaded PCL/F68 blend microspheres were found to own a faster release rate and a remarkably controlled release behavior.