Hypoglycemic effect of insulin-loaded hydrogel-nanogel composite on streptozotocin-induced diabetic rats.

At present, how to increase insulin rapidly, availably and stably is still a conundrum in the treatment of diabetes mellitus. In vitro studies have shown that insulin can be released from hydrogel-nanogel composite according to the changes of glucose level. This study aimed to observe the glucose-lowering effects and evaluate the safety of the insulin-loaded hydrogel-nanogel composite in diabetic rats. We found that significant glycemic regulation could be observed up to 30 hours after subcutaneous injection, and the fasting blood glucose was reduced effectively. The result of an oral glucose tolerance test showed that the level of insulin expressed a stable increase from 0.5 hours to 3.5 hours, which led to a reduction of glucose with steady steps. Also, compared with Ins group, the Gel+Ins group showed slighter skin and pancreas damage, while the oxidative stress and inflammation response were similar to the normal control group. In conclusion, these results demonstrated that the glucose-lowering action of the insulin-loaded hydrogel-nanogel composite was superior to that of the regular insulin, and might thus become an insulin carrier in the future.

Nitrilotriacetic Acid-Functionalized Glucose-Responsive Complex Micelles for the Efficient Encapsulation and Self-Regulated Release of Insulin.

Insulin plays a significant role in diabetes treatment. Although a huge number of insulin-loaded, glucose-responsive nanocarriers have been developed in past decades, most of them showed a lower loading capacity and efficiency due to the weak interaction between insulin and nanocarriers. In this work, a novel insulin-encapsulated glucose-responsive polymeric complex micelle (CM) is devised, showing (i) enhanced insulin-loading efficiency owing to the zinc ions' chelation by nitrilotriacetic acid (NTA) groups of NTA-functioned glycopolymer and the histidine imidazole of insulin, (ii) the glucose-triggered pulse release of insulin, and (iii) long stability under physiological conditions. This CM was fabricated by the self-assembly of block copolymer PEG- b-P(Asp- co-AspPBA) and glycopolymer P(Asp- co-AspGA- co-AspNTA), resulting in complex micelles with a PEG shell and a cross-linked core composed of phenylboronic acid (PBA)/glucose complexations. Notably, the modified nitrilotriacetic acid (NTA) groups of CM could specifically bind insulin via chelated zinc ions, thus enhancing the loading efficacy of insulin compared to that of nonmodified CM. The dynamic PBA/glucose complexation core of CM dissociates under the trigger of high glucose concentration (>2 g/L) while being quite stable in low glucose concentrations (<2 g/L), as demonstrated by the pulse release of insulin in vitro. Finally, in a murine model of type 1 diabetes, NTA-modified complex micelles loading an insulin (NTA-CM-INS) group exhibited a long hypoglycemic effect which is superior to that of free insulin in the PBS (PBS-INS) group and insulin-loaded complex micelles without an NTA modification (CM-INS) group. This long-term effect benefited from Zn(II) chelation by NTA-modified complex micelles and could avoid hypoglycemia caused by the burst release of insulin. Taken together, this constitutes a highly effective way to encapsulate insulin and release insulin via an on-demand manner for blood glucose control in diabetes.

Core/Shell Gene Carriers with Different Lengths of PLGA Chains to Transfect Endothelial Cells.

In order to improve the transfection efficiency and reduce the cytotoxicity of gene carriers, many strategies have been used to develop novel gene carriers. In this study, five complex micelles (MSP(2 k), MSP(4 k), MSP(6 k), MSP(8 k), and MSP(10 k)) were prepared from methoxy-poly(ethylene glycol)-b-poly(d,l-lactide-co-glycolide) (mPEG-b-PLGA) and sorbitol-poly(d,l-lactide-co-glycolide)-graft-PEI (sorbitol-PLGA-g-PEI, where the designed molecular weights of PLGA chains were 2 kDa, 4 kDa, 6 kDa, 8 kDa, and 10 kDa, respectively) copolymers by a self-assembly method, and the mass ratio of mPEG-b-PLGA to sorbitol-PLGA-g-PEI was 1/3. These complex micelles and their gene complexes had appropriate sizes and zeta potentials, and pEGFP-ZNF580 (pDNA) could be efficiently internalized into EA.hy926 cells by their gene complexes (MSP(2 k)/pDNA, MSP(4 k)/pDNA, MSP(6 k)/pDNA, MSP(8 k)/pDNA, and MSP(10 k)/pDNA). The MTT assay results demonstrated that the gene complexes had low cytotoxicity in vitro. When the hydrophobic PLGA chain increased above 6 kDa, the gene complexes showed higher performance than that prepared from short hydrophobic chains. Moreover, the relative ZNF580 protein expression levels in MSP(6 k)/pDNA, MSP(8 k)/pDNA, and MSP(10 k)/pDNA) groups were 79.6%, 71.2%, and 73%, respectively. These gene complexes could promote the transfection of endothelial cells, while providing important information and insight for the design of new and effective gene carriers to promote the proliferation and migration of endothelial cells.

Sustained viral response and treatment-induced cytopenia correlate with SLCs and KLF12 genotypes in interferon/ribavirin-treated Chinese chronic hepatitis C patients.

BACKGROUND AND AIM: Genetic variations in solute carrier (SLC) genes are associated with liver diseases, and Kruppel-like factor 12 (KLF12) affects the b chain of hemoglobin. We investigated possible correlations of SLC and KLF12 polymorphisms with viral clearance (spontaneous and treatment-induced) and adverse effects in Chinese chronic hepatitis C (CHC) patients. METHODS: We genotyped the single nucleotide polymorphisms in 525 CHC patients, 137 patients with spontaneous clearance, and 207 healthy controls. Three hundred fifty-seven CHC patients received recombinant interferon-alpha2b/ribavirin (IFN-α2b/RBV) treatment, and 175 patients were chosen for analysis of drug-induced cytopenia. All raw P-values were corrected by the Bonferroni method. RESULTS: A higher rate of sustained viral response was detected in patients with SLC4A11 rs3810560 CC variant versus TT/TC variant (76.9% vs 59.2%; OR, 2.42; 95% CI, 1.06-5.56, P = 0.037 after adjustment), but there was no significant difference among different hepatitis C virus genotypes. RBV-induced anemia was independently correlated with SLC29A1 rs760370 AA genotype (OR, 2.90; 95% CI, 1.29-6.54, P = 0.010), and the severity of IFN-induced thrombocytopenia was related to GG genotype (OR, 4.98; 95% CI, 1.27-19.61; P = 0.021); the detected effects held true for HCV-2a patients but weakened in HCV-1b patients. A reactive increase in platelet count was closely associated with KLF12 rs9543524 TT variant. CONCLUSION: SLC4A11 rs3810560 polymorphism independently affected the sustained viral response rates in CHC patients, whereas SLC29A1 rs760370 and KLF12 rs9543524 single nucleotide polymorphisms correlated with treatment-induced adverse events. Clearly, the predictive power varied with HCV genotypes and the reason for genotype-dependent discrepancy was not fully understood.

Surface modification and endothelialization of biomaterials as potential scaffolds for vascular tissue engineering applications.

Surface modification and endothelialization of vascular biomaterials are common approaches that are used to both resist the nonspecific adhesion of proteins and improve the hemocompatibility and long-term patency of artificial vascular grafts. Surface modification of vascular grafts using hydrophilic poly(ethylene glycol), zwitterionic polymers, heparin or other bioactive molecules can efficiently enhance hemocompatibility, and consequently prevent thrombosis on artificial vascular grafts. However, these modified surfaces may be excessively hydrophilic, which limits initial vascular endothelial cell adhesion and formation of a confluent endothelial lining. Therefore, the improvement of endothelialization on these grafts by chemical modification with specific peptides and genes is now arousing more and more interest. Several active peptides, such as RGD, CAG, REDV and YIGSR, can be specifically recognized by endothelial cells. Consequently, graft surfaces that are modified by these peptides can exhibit targeting selectivity for the adhesion of endothelial cells, and genes can be delivered by targeting carriers to specific tissues to enhance the promotion and regeneration of blood vessels. These methods could effectively accelerate selective endothelial cell recruitment and functional endothelialization. In this review, recent developments in the surface modification and endothelialization of biomaterials in vascular tissue engineering are summarized. Both gene engineering and targeting ligand immobilization are promising methods to improve the clinical outcome of artificial vascular grafts.

Use of parenteral caffeinum natrio-benzoicum: an underestimated risk factor for HCV transmission in China.

BACKGROUND: Fuyu city in China has a high prevalence of hepatitis C virus (HCV) infection resulting in a high morbidity and mortality from chronic liver disease and hepatocellular carcinoma. This study was conducted to identify the risk factors for HCV infection in Fuyu city. METHODS: Recruitment of study subjects involved a cross-sectional survey using non-random, convenience sampling. Information on demographic variables, risk factors for HCV infection, clinical manifestations, behavioral practices and family history was collected by administering a questionnaire. Anti-HCV antibody was detected using Abbott ARCHITECT i2000SR. HCV infection was confirmed by HCV-RNA testing by the Roche Taqman HCV test. Univariate and multivariate analyses were performed to identify the factors associated with HCV infection. RESULTS: Out of 3,228 persons that participated in the survey, 3,219 were enrolled in the study. The prevalence of HCV infection was 42.1 % (1355/3219). Among 734 patients with chronic HCV infection whose HCV-RNA genotyping was performed, genotype 1b was the most common (58.0 %), followed by genotype 2a (40.2 %), while co-infection with genotypes 1b and 2a was detected in 1.8 % of the subjects. On univariate analysis, male gender, older age, parenteral caffeinum natrio-benzoicum and share syringes (PCNBSS), and nine other factors were significantly associated with HCV infection. After adjusting for potential confounders, male gender, old age, cigarette smoking, lower education level, history of blood transfusion, blood donation, prior dental surgery, and PCNBSS were found to be independently associated with HCV infection. CONCLUSIONS: The prevalence of HCV infection is likely to be high among residents in Fuyu and we observed that genotypes 1b and 2a dominated in the city. Our findings support the hypothesis that PCNBSS which became endemic in Fuyu city during 1970s-1980s is strongly associated with HCV positivity.

Electrospun scaffolds of silk fibroin and poly(lactide-co-glycolide) for endothelial cell growth.

Electrospun scaffolds of silk fibroin (SF) and poly(lactide-co-glycolide) (PLGA) were prepared to mimic the morphology and chemistry of the extracellular matrix. The SF/PLGA scaffolds were treated with ethanol to improve their usability. After ethanol treatment the scaffolds exhibited a smooth surface and uniform fibers. SF transformed from random coil conformation to ß-sheet structure after ethanol treatment, so that the SF/PLGA scaffolds showed low hydrophilicity and dissolving rate in water. The mechanical properties and the hydrophilicity of the blended fibrous scaffolds were affected by the weight ratio of SF and PLGA. During degradation of ethanol-treated SF/PLGA scaffolds in vitro, the fibers became thin along with the degradation time. Human umbilical vein endothelial cells (HUVECs) were seeded onto the ethanol-treated nanofibrous scaffolds for cell viability, attachment and morphogenesis studies. These SF/PLGA scaffolds could enhance the viability, spreading and attachment of HUVECs. Based on these results, these ethanol-treated scaffolds are proposed to be a good candidate for endothelial cell growth.

Glucose-responsive complex micelles for self-regulated delivery of insulin with effective protection of insulin and enhanced hypoglycemic activity in vivo.

Large amounts of insulin-loaded glucose-responsive micelles based on poly(amino acid)s have been developed for diabetes treatment over last decades, but most of them could not effectively protect insulin from enzymatic degradation in vivo because the micellar core was biodegradable and lacked protective structure for insulin, which would lower the efficacy of insulin to a large extent. In this study, we fabricated a new type of insulin-loaded glucose-responsive complex micelles (CMs), which were self-assembled by a phenylboronic acid (PBA)-modified block copolymer PEG-b-P(Asp-co-AspPBA) and a glucosamine (GA)/nitrilotriacetic acid (NTA)-functionalized block copolymer PNIPAM-b-P(Asp-co-AspGA-co-AspNTA), for self-regulated delivery of insulin with effective protection of insulin and enhanced hypoglycemic activity in vivo. The CMs possessed mixed shell of PEG/PNIPAM and cross-linked core of PBA/GA complex, which could be disintegrated under the condition of high glucose concentration (5 g/L) while maintaining stable at low glucose concentration (1 g/L). The NTA groups of CMs greatly improved the loading content of insulin by specifically bind insulin via the chelated zinc ions. More importantly, PNIPAM chains in the mixed shell would collapse under 37 °C and form hydrophobic domains around the micellar core, which could significantly protect the micellar core as well as the encapsulated insulin from attacking by external proteases. In a murine model of type 1 diabetes, the CMs with insulin chelated by NTA showed a long hypoglycemic effect, which is superior to insulin-loaded simple micelles without PNIPAM and insulin in PBS buffer (pH 7.4). Therefore, this kind of CMs could be a potential candidate for insulin delivery in diabetes therapy.

Glucose and H2O2 dual-sensitive nanogels for enhanced glucose-responsive insulin delivery.

Diabetes is a chronic metabolic disorder disease characterized by high blood glucose levels and has become one of the most serious threats to human health. In recent decades, a number of insulin delivery systems, including bulk gels, nanogels, and polymeric micelles, have been developed for the treatment of diabetes. Herein, a kind of glucose and H2O2 dual-responsive polymeric nanogel was designed for enhanced glucose-responsive insulin delivery. The polymeric nanogels composed of poly(ethylene glycol) and poly(cyclic phenylboronic ester) (glucose and H2O2 dual-sensitive groups) were synthesized by a one-pot thiol-ene click chemistry approach. The nanogels displayed glucose-responsive release of insulin and the release rate could be promoted by the incorporation of glucose oxidase (GOx), which generated H2O2 at high glucose levels and H2O2 further oxidizes and hydrolyzes the phenylboronic ester group. The nanogels have characteristics of long blood circulation time, a fast response to glucose, and excellent biocompatibility. Moreover, subcutaneous delivery of insulin to diabetic mice with the insulin/GOx-loaded nanogels presented an effective hypoglycemic effect compared to that of injection of insulin or insulin-loaded nanogels. This kind of nanogel would be a promising candidate for the delivery of insulin in the future.

Epstein-Barr virus is associated with periodontal diseases: A meta-analysis based on 21 case-control studies.

Some controversies still exist between the detection of Epstein-Barr virus (EBV)'s DNA and risks of periodontal diseases. Hence, a comprehensive meta-analysis on all available literatures was performed to clarify the relationship between EBV and preidontitis.A comprehensive search was conducted within the PUBMED, EMBASE, and WANFANG databases up to October 10th, 2016 according to inclusion and exclusion criteria and finally 21 case-control literatures were obtained. The outcomes including odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of associations. Publication bias was determined by Begg or Egger test. Sensitivity analysis was used to investigate reliability and stability of the results.According to the data from included trials, the association between overall increased risks of periodontitis and the detection of EBV was significant (OR = 6.199, 95% CI = 3.119-12.319, P < 0.001). In the disease-type analysis, the pooled ORs for chronic periodontitis and aggressive periodontitis were 6.586 (95% CI = 3.042-14.262, P < 0.001) and 8.361 (95% CI = 2.109-33.143, P = 0.003), respectively. In the subgroup analysis of ethnicity, our results suggested that high EBV-detecting frequencies were correlated with increased risks of periodontitis in Asians, Europeans, and Americans (P < 0.001). Subgroup analysis by the sample type showed that subgingival plaque (SgP) samples and tissue samples were available for EBV detecting (P < 0.001). Detecting EBV of samples in ≥5 (6) mm sites of periodontal pockets were easier than in ≤3-mm sites (P = 0.023).This meta-analysis indicates that high frequent detection of EBV correlates with increased risk of periodontal diseases. SgP and tissue are available for detecting EBV in patients of periodontitis. At last, our results suggest that detecting EBV of samples in =5 (6) mm sites of periodontal pockets are more sensitive than in ≤3-mm sites.

Star-shaped copolymer grafted PEI and REDV as a gene carrier to improve migration of endothelial cells.

In this work, a biodegradable star-shaped copolymer poly(lactide-co-3(S)-methyl-morpholine-2,5-dione)6 (Star-(PLMD)6) was synthesized via ring-opening polymerization (ROP), and subsequently a gene carrier Star-PLMD-g-PEI-g-PEG-CREDVW was prepared by grafting polyethyleneimine (PEI), polyethylene glycol (PEG) and targeting peptide REDV onto Star-(PLMD)6. This gene carrier could form stable micelles to condense pEGFP-ZNF580 through electrostatic interaction. The resulting complexes were biocompatible and showed high efficiency in gene delivery. In addition, these complexes exhibited high selectivity for endothelial cells (ECs), high transfection efficiency and enhanced migration of ECs. The protein level of ZNF580 expression was significantly high (up to 85%), while the control group was only 51%. This combination of degradability, targeting ligand and star-structure strategy exhibits a significant advantage in transfection efficiency and migration of ECs.

CREDVW-Linked Polymeric Micelles As a Targeting Gene Transfer Vector for Selective Transfection and Proliferation of Endothelial Cells.

Nowadays, gene transfer technology has been widely used to promote endothelialization of artificial vascular grafts. However, the lack of gene vectors with low cytotoxicity and targeting function still remains a pressing challenge. Herein, polyethylenimine (PEI, 1.8 kDa or 10 kDa) was conjugated to an amphiphilic and biodegradable diblock copolymer poly(ethylene glycol)-b-poly(lactide-co-glycolide) (mPEG-b-PLGA) to prepare mPEG-b-PLGA-g-PEI copolymers with the aim to develop gene vectors with low cytotoxicity while high transfection efficiency. The micelles were prepared from mPEG-b-PLGA-g-PEI copolymers by self-assembly method. Furthermore, Cys-Arg-Glu-Asp-Val-Trp (CREDVW) peptide was linked to micelle surface to enable the micelles with special recognition for endothelial cells (ECs). In addition, pEGFP-ZNF580 plasmids were condensed into these CREDVW-linked micelles to enhance the proliferation of ECs. These CREDVW-linked micelle/pEGFP-ZNF580 complexes exhibited low cytotoxicity by MTT assay. The cell transfection results demonstrated that pEGFP-ZNF580 could be transferred into ECs efficiently by these micelles. The results of Western blot analysis showed that the relative ZNF580 protein level in transfected ECs increased to 76.9%. The rapid migration of transfected ECs can be verified by wound healing assay. These results indicated that CREDVW-linked micelles could be a suitable gene transfer vector with low cytotoxicity and high transfection efficiency, which has great potential for rapid endothelialization of artificial blood vessels.

Surface tailoring for selective endothelialization and platelet inhibition via a combination of SI-ATRP and click chemistry using Cys-Ala-Gly-peptide.

Surface tailoring is an attractive approach to enhancing selective endothelialization, which is a prerequisite for current vascular prosthesis applications. Here, we modified polycarbonate urethane (PCU) surface with both poly(ethylene glycol) and Cys-Ala-Gly-peptide (CAG) for the purpose of creating a hydrophilic surface with targeting adhesion of endothelial cells (ECs). In the first step, PCU-film surface was grafted with poly(ethylene glycol) methacrylate (PEGMA) to covalently tether hydrophilic polymer brushes via surface initiated atom transfer radical polymerization (SI-ATRP), followed by grafting of an active monomer pentafluorophenyl methacrylate (PFMA) by a second ATRP. The postpolymerization modification of the terminal reactive groups with allyl amine molecules created pendant allyl groups, which were subsequently functionalized with cysteine terminated CAG-peptide via photo-initiated thiol-ene click chemistry. The functionalized surfaces were characterized by water contact angle and XPS analysis. The growth and proliferation of human ECs or human umbilical arterial smooth muscle cells on the functionalized surfaces were investigated for 1, 3 and 7 day/s. The results indicated that these peptide functionalized surfaces exhibited enhanced EC adhesion, growth and proliferation. Furthermore, they suppressed platelet adhesion in contact with platelet-rich plasma for 2h. Therefore, these surfaces with EC targeting ligand could be an effective anti-thrombogenic platform for vascular tissue engineering application.

Functionalization of polycarbonate surfaces by grafting PEG and zwitterionic polymers with a multicomb structure.

The hemocompatibility of polycarbonateurethane (PCU) surfaces is improved by decoration with poly(poly(ethylene glycol) methacrylate) (poly(PEGMA)) and zwitterionic poly(3-((2-(methacryloyloxy)ethyl)dimethylammonio)propane-1-sulfonate) (poly(DMAPS)) blocks providing a novel multicomb structure obtained by application of surface-initiated atom transfer radical polymerization (s-ATRP) conditions. The PCU-poly(PEGMA-g-DMAPS) surface shows high hydrophilicity with a low contact angle of 20.6 ± 1.8°, while PCU-poly(PEGMA-b-DMAPS) surface exhibitsed a contact angle of 30.5 ± 2.6°. Furthermore, PCU-poly(PEGMA-g-DMAPS) surface shows very low platelet adsorption indicating that multicomb structure modified PCUs are preferred candidate materials for blood-contacting materials.