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Silk fibroin (SF) as a natural biopolymer has become a popular material for biomedical applications due to its minimal immunogenicity, tunable biodegradability, and high biocompatibility. Nowadays, various techniques have been developed for the applications of SF in bioengineering. Most of the literature reviews focus on the SF-based biomaterials and their different forms of applications such as films, hydrogels, and scaffolds. SF is also valuable as a coating on other substrate materials for biomedicine; however, there are few reviews related to SF-coated biomaterials. Thus, in this review, we focused on the surface modification of biomaterials using SF coatings, demonstrated their various preparation methods on substrate materials, and introduced the latest procedures. The diverse applications of SF coatings for biomedicine are discussed, including bone, ligament, skin, mucosa, and nerve regeneration, and dental implant surface modification. SF coating is conducive to inducing cell adhesion and migration, promoting hydroxyapatite (HA) deposition and matrix mineralization, and inhibiting the Notch signaling pathway, making it a promising strategy for bone regeneration. In addition, SF-coated composite scaffolds can be considered prospective candidates for ligament regeneration after injury. SF coating has been proven to enhance the mechanical properties of the substrate material, and render integral stability to the dressing material during the regeneration of skin and mucosa. Moreover, SF coating is a potential strategy to accelerate nerve regeneration due to its dielectric properties, mechanical flexibility, and angiogenesis promotion effect. In addition, SF coating is an effective and popular means for dental implant surface modification to promote osteogenesis around implants made of different materials. Thus, this review can be of great benefit for further improvements in SF-coated biomaterials, and will undoubtedly contribute to clinical transformation in the future.
Subject(s)
Biocompatible Materials/chemistry , Silk/chemistry , Fibroins/pharmacology , Dental Implants , Osteogenesis , Tissue Scaffolds/chemistry , Tissue Engineering/methodsABSTRACT
Objective To investigate the dynamic changes of regulatory T cells (Treg ) and the surface expression of programmed death (PD)‐1 and the level of transforming growth factor (TGF )‐βduring antiviral treatment in patients with chronic hepatitis C (CHC) .Methods Eighty‐six CHC patients referred to the First Affiliated Hospital of Zhengzhou University from October 2012 to October 2013 were included ,and all of them were administered with pegylated interferon α‐2a and ribavirin .Thirty healthy controls were enrolled .The percentage of Treg cells ,PD‐1 expression and TGF‐β level were analyzed by flow cytometry at baseline and at time of achieving rapid virological response (RVR ) , early viral virological (EVR ) , end‐of‐treatment virological response (ETVR ) and sustained virological response (SVR) ,or not achieving SVR .Comparison between two groups was analyzed by t test .Results Among 86 CHC patients ,the proportions of RVR ,EVR ,ETVR ,and SVR at week 24 of follow‐up were 29 cases ,67 cases ,79 cases and 67 cases ,respectively .Percentage of Treg cells in CHC patients was much higher than that in healthy controls (10 .31 ± 5 .61 vs 2 .18 ± 0 .65 ,t = 2 .28 , P< 0 .05) .During antiviral therapy ,percentages of Treg cells declined ,not only in CHC patients with HCV genotype 1b (at baseline , RVR ,EVR ,and ETVR :14 .44 ± 3 .78 ,11 .01 ± 1 .79 ,8 .24 ± 2 .98 ,and 5 .36 ± 1 .47 ,respectively ) ,but also in those infected with HCV genotype 2a (at baseline ,RVR ,EVR ,and ETVR :12 .34 ± 2 .82 ,8 .99 ± 1 .68 ,7 .53 ± 2 .96 ,and 4 .79 ± 1 .23 ,respectively ) .Expressions of PD‐1 and TGF‐β also decreased .At baseline ,the expressions of PD‐1 in patients with SVR and without SVR were 29 .11 ± 14 .65 and 37 .73 ± 11 .65 ,respectively (t = 2 .15 , P = 0 .04) ,and the levels of TGF‐β were 41 .20 ± 18 .96 and 56 .75 ± 14 .42 ,respectively (t= 2 .66 ,P< 0 .01) .At week 24 ,the expressions of PD‐1 in patients with SVR and without SVR were 10 .36 ± 4 .81 and 36 .46 ± 10 .52 ,respectively (t= 13 .95 ,P< 0 .01) ,and the levels of TGF‐β were 10 .06 ± 4 .64 and 45 .23 ± 17 .85 , respectively ( t = 11 .85 , P < 0 .01 ) . Conclusions Percentages of Treg cells and expressions of PD‐1 and TGF‐β decrease during antiviral treatment in CHC patients .Thus ,it could be of assist to predict the treatment response by monitoring these parameters .
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Objective: To study the effect and the mechanism of acute hypoxia on Ca2+-ATPase inhibitor, cyclopiazonic acid (CPA) induced intracellular calcium cation enhancement in rat distal pulmonary venous smooth muscle cells (PVSMC) . Methods: The PVSMC were isolated from 6 male SD rats and the cells were cultured for further experiment. Enhancing effects of CPA, acute hypoxia (4% O2) on [Ca2+]i in distal PVSMC and the interventional effects of 2 store-operated Ca2+ channels (SOCC) inhibitors, NiCl2 and SKF96365 on [Ca2+]i in distal PVSMC were tested by lfuorescence microscope and intracellular [Ca2+] examining system. Results: When PVSMC were perfused with Ca2+-free Krebs solution containing 5 μmol/L nifedipine, 10 μmol/L CPA caused a slight elevation of [Ca2+]i, and acute hypoxia obviously enhanced the [Ca2+]i in PVSMC. When restoration of extracellular [Ca2+] to 2.5 mmol/L, 10 μmol/L CPA caused signiifcant elevation of [Ca2+]i, and acute hypoxia obviously enhanced [Ca2+]i induced by CPA in PVSMC. The SOCC inhibitors, NiCl2 (500 μmol/L) and SKF96365 (50 μmol/L) distinctively attenuated the elevation of [Ca2+]i by hypoxia and CPA. However, NiCl2 and SKF96365 had no effect on high potassium (60 mmol/L KCl Krebs solution) induced elevation of [Ca2+]i in distal PVSMC. Conclusion: Acute hypoxia enhanced the elevation of [Ca2+]i induced by CPA; such effect could be selectively blocked by SOCC inhibitor which indicated that acute hypoxia could enhance the activity of SOCC in rat distal PVSMC.
ABSTRACT
Objective To study the effect of SKF96365 and NiCl2 on cyclopiazonic acid (CPA) induced intracellular calcium cation concentration ([Ca2+ ]i ) change in rat distal pulmonary arterial smooth muscle cells (PASMC) .Methods The rat distal PASMC were isolated and cultured .The effects of CPA ,SKF96365 and NiCl2 on [Ca2+ ]i in PASMC were tested by fluorescence microscope and InCyte [Ca2+ ]i measurement system .Results PASMC were incubated with Ca2+‐free Krebs solution containing 5μmol/L nifedipine ,10 μmol/L CPA caused a small transient increase in [Ca2+ ]i ;after restoration of extracellular Ca2+ to 2 .5 mmol/L ,10 μmol/L CPA caused marked increases in [Ca2+ ]i in PASMC incubated with Krebs solution containing 5 μmol/L nife‐dipine .Both 50 μmol/L SKF96365 and 500 μmol/L NiCl2 distinctly attenuated the increases in [Ca2+ ]i caused by 10 μmol/L CPA in PASMC .However ,neither 50 μmol/L SKF96365 nor 500 μmol/L NiCl2 affected the increases in [Ca2+ ]i caused by 60 mmol/L KCl in PASMC .Conclusion CPA induced increases in [Ca2+ ]i may related to Ca2+ release from sarcoplasmic reticulum and the in‐flux of Ca2+ through store‐operated Ca2+ channels (SOCC) in rat distal PASMC .Both SKF96365 and NiCl2 could selectively block SOCC and attenuated the influx of Ca2+ through SOCC in PASMC .