Organismal Function Enhancement through Biomaterial Intervention.

Living organisms in nature, such as magnetotactic bacteria and eggs, generate various organic-inorganic hybrid materials, providing unique functionalities. Inspired by such natural hybrid materials, researchers can reasonably integrate biomaterials with living organisms either internally or externally to enhance their inherent capabilities and generate new functionalities. Currently, the approaches to enhancing organismal function through biomaterial intervention have undergone rapid development, progressing from the cellular level to the subcellular or multicellular level. In this review, we will concentrate on three key strategies related to biomaterial-guided bioenhancement, including biointerface engineering, artificial organelles, and 3D multicellular immune niches. For biointerface engineering, excess of amino acid residues on the surfaces of cells or viruses enables the assembly of materials to form versatile artificial shells, facilitating vaccine engineering and biological camouflage. Artificial organelles refer to artificial subcellular reactors made of biomaterials that persist in the cytoplasm, which imparts cells with on-demand regulatory ability. Moreover, macroscale biomaterials with spatiotemporal regulation characters enable the local recruitment and aggregation of cells, denoting multicellular niche to enhance crosstalk between cells and antigens. Collectively, harnessing the programmable chemical and biological attributes of biomaterials for organismal function enhancement shows significant potential in forthcoming biomedical applications.

Manganese-mineralized cancer cells as immunogenic cancer vaccines for tumor immunotherapy.

The strategy of using tumor cells to construct whole-cell cancer vaccines has received widespread attention. However, the limited immunogenicity of inactivated tumor cells and the challenge of overcoming immune suppression in solid tumors have hindered the application of whole-cell-based cancer immune therapy. Inspired by the regulatory effects of MnO2 and spatiotemporal control capability of material layers in cell surface engineering, we developed a manganese (Mn)-mineralized tumor cell, B16F10@MnO2, by inactivating B16F10 melanoma cells with KMnO4 to generate manganese-mineralized tumor cells. The cell-based composite was formed by combining amorphous MnO2 with the membrane structure of cells based on the redox reaction between KMnO4 and tumor cells. The MnO2 layer induced a stronger phagocytosis of ovalbumin (OVA)-expressing tumor cells by antigen presenting cells than formaldehyde-fixed cells did, resulting in specific antigen-presentation in vitro and in vivo and subsequent immune responses. Intratumoral therapy with B16F10@MnO2 inhibited B16F10 tumor growth. Moreover, the infiltration of CD8+ T cells within B16F10 solid tumors and the proportion of central memory T cells both increased in B16F10@MnO2 treated tumor-bearing mice, indicating enhanced adaptive immunity. This study provides a convenient and effective method to improve whole-cell-based anti-tumor therapy.

Measurement of Five Emotions Defined by Traditional Chinese Medicine With a Focus on Preventing Mild Cognitive Impairment.

Objectives: This study aimed to develop a novel Measurement of the Five Emotions (MFE) based on traditional Chinese medicine for assessing cognitive impairment in elderly individuals. Methods: Surveys were collected from 184 participants, over 65 years of age, who were residents of Kyoto City, Japan. The surveys included the Measurement of the Five Emotions (MFE) and the Dementia Assessment Sheet for the Community-based Integrated Care System (DASC-21). Item-total reliability and internal consistency reliability were assessed using Spearman's correlation test and Cronbach's alpha coefficient analysis. Factor analysis was conducted to identify the main factors related to the theoretically constructed emotional reaction patterns. Criterion-related validity was examined by investigating the correlation between the scores of the 2 surveys (MFE and DASC-21). Results: The factor analysis revealed that the final version of MFE consisted of 5 factors, which accounted for a cumulative contribution rate of 57.71%. The Cronbach's alpha coefficient reached .71, indicating satisfactory internal consistency. There was a negative correlation between the MFE and DASC-21 scores with a correlation coefficient of -.3149. Furthermore, when comparing participants with lower cognitive function (DASC-21 score >26) to those with higher cognitive function, MFE subscale scores in the emotions of "Sorrow" and "Thought" were significantly lower, suggesting that these particular emotions are related to cognitive impairment. These findings confirmed the reliability and the construct validity of the MFE. Conclusion: The criterion reliability and validity tests provided evidence for the construct validity of the MFE. The negative correlation (coefficient = -.3149) between MFE scores and DASC-21 scores suggested that MFE can serve as a scale for detecting cognitive impairment.

Material-engineered bioartificial microorganisms enabling efficient scavenging of waterborne viruses.

Material-based tactics have attracted extensive attention in driving the functional evolution of organisms. In aiming to design steerable bioartificial organisms to scavenge pathogenic waterborne viruses, we engineer Paramecium caudatum (Para), single-celled microorganisms, with a semiartificial and specific virus-scavenging organelle (VSO). Fe3O4 magnetic nanoparticles modified with a virus-capture antibody (MNPs@Ab) are integrated into the vacuoles of Para during feeding to produce VSOs, which persist inside Para without impairing their swimming ability. Compared with natural Para, which has no capture specificity and shows inefficient inactivation, the VSO-engineered Para (E-Para) specifically gathers waterborne viruses and confines them inside the VSOs, where the captured viruses are completely deactivated because the peroxidase-like nano-Fe3O4 produces virus-killing hydroxyl radicals (•OH) within acidic environment of VSO. After treatment, magnetized E-Para is readily recycled and reused, avoiding further contamination. Materials-based artificial organelles convert natural Para into a living virus scavenger, facilitating waterborne virus clearance without extra energy consumption.

Association of the rs1990760, rs3747517, and rs10930046 polymorphisms in the IFIH1 gene with susceptibility to autoimmune diseases: a meta-analysis.

Objective: Interferon induced with helicase C domain 1 (IFIH1) single-nucleotide polymorphisms (SNP) rs1990760, rs3747517, and rs10930046 have been shown to be closely related to the risk of autoimmune diseases. The aim of this study was firstly to examine the association of the rs1990760 with type 1 diabetes (T1D) in a Chinese population. Secondly, to assess the association of SNP rs1990760, rs3747517, and rs10930046 with autoimmune diseases susceptibility. Methods: A total of 1,273 T1D patients and 1,010 healthy control subjects in a Chinese population were enrolled in this case-control study. Subsequently, we performed a meta-analysis on the association of the SNP rs1990760, rs3747517, and rs10930046 in the IFIH1 gene with susceptibility to autoimmune diseases. The random and fixed genetic effects models were used to evaluate the association and the effect sizes, including odds ratios (OR) and 95% confidence intervals (CI). Stratification analyses based on ethnicity and the type of autoimmune diseases were performed. Results: IFIH1 SNP rs1990760 was not associated with a significant risk of T1D in the Chinese population in the case-control study. A total of 35 studies including 70,966 patients and 124,509 controls were identified and included in the meta-analysis. The results displayed significant associations between IFIH1 rs1990760 A allele and rs3747517 C allele and autoimmune diseases risk (OR=1.09, 95% CI: 1.01~1.17; OR=1.24, 95% CI: 1.15~1.25, respectively). Stratified analysis indicated a significant association rs1990760 and rs3747517 with autoimmune diseases risk in the Caucasian population (OR=1.11, 95% CI: 1.02~1.20, OR=1.29, 95% CI: 1.18~1.41, respectively). Conclusions: This study revealed no association between IFIH1 SNP rs1990760 and T1D in Chinese. Furthermore, the meta-analysis indicated that rs1990760 and rs3747517 polymorphisms, confer susceptibility to autoimmune diseases, especially in the Caucasian population.

Immunization against Zika by entrapping live virus in a subcutaneous self-adjuvanting hydrogel.

The threat of new viral outbreaks has heightened the need for ready-to-use vaccines that are safe and effective. Here we show that a subcutaneous vaccine consisting of live Zika virus electrostatically entrapped in a self-adjuvanting hydrogel recruited immune cells at the injection site and provided mice with effective protection against a lethal viral challenge. The hydrogel prevented the escape of the viral particles and upregulated pattern recognition receptors that activated innate antiviral immunity. The local inflammatory niche facilitated the engulfment of the virus by immune cells infiltrating the hydrogel, the processing and cross-presentation of antigens and the expansion of germinal centre B cells and induced robust antigen-specific adaptive responses and immune memory. Inflammatory immune niches entrapping live viruses may facilitate the rapid development of safe and efficacious vaccines.

The m6A methylation profiles of immune cells in type 1 diabetes mellitus.

Background: Type 1 diabetes mellitus (T1DM) is caused by immune cell-mediated ß-cell dysfunction. In recent decades, N6-methyladenosine (m6A) has attracted widespread attention in the scientific research field because it plays vital roles in the pathogenesis of immunity-related diseases, including autoimmune diseases. However, neither the m6A modification profile nor the potential role it plays in T1DM pathogenesis has been investigated to date. Materials and Methods: An m6A mRNA epitranscriptomic microarray analysis was performed to analyze m6A regulator expression patterns and m6A methylation patterns in immune cells of T1DM patients (n=6) and healthy individuals (n=6). A bioinformatics analysis was subsequently performed to explore the potential biological functions and signaling pathways underlying T1DM pathogenesis. Furthermore, mRNA expression and m6A methylation levels were subsequently verified by qRT-PCR and methylated RNA immunoprecipitation-qPCR (MeRIP-qPCR), respectively, in the T1DM and healthy groups (n=6 per group). Results: Among the multiple m6A regulators, METTL3 and IGF2BP2 had significantly downregulated expression, and YTHDC1 and HNRNPA2B1 had significantly upregulated expression in the T1DM group relative to the healthy group. The microarray analysis revealed 4247 differentially methylated transcripts, including 932 hypermethylated and 3315 hypomethylated transcripts, and 4264 differentially expressed transcripts, including 1818 upregulated transcripts and 2446 downregulated transcripts in the T1DM group relative to the healthy group. An association analysis between methylation and gene expression demonstrated that the expression of 590 hypermethylated transcripts was upregulated, and that of 1890 hypomethylated transcripts was downregulated. Pearson correlation analysis showed significant correlations between the expression levels of differentially expressed m6A regulators and the methylation levels of differentially methylated transcripts and significant correlations between the expression levels of differentially expressed m6A regulators and that of differentially expressed transcripts. Moreover, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses demonstrated that differentially methylated transcripts were involved in pathways related to immunity, including some closely associated with T1DM. Conclusions: Our study presents m6A regulator expression patterns and m6A methylation patterns of immune cells in T1DM, showing that the m6A mark and m6A regulators are promising targets for T1DM diagnosis and treatment.

3D Technique-Based Nonsurgical Correction of Deformational Congenital Auricular Deformities.

INTRODUCTION: Congenital auricular deformity (CAD) is a common postpartum deformity, and nonsurgical correction of CAD has been recognized as a safe and effective approach. Three-dimensional (3D) technique has been used in surgical reconstruction of unilateral microtia; however, 3D technique used in nonsurgical correction for deformational CAD has not been reported. METHODS: In this study, 12 CAD patients aged from 0.6 to 7 months with 16 deformational CAD were treated with 3D technique-based personalized nonsurgical correction (3D-NSC). Patients' CAD was photographed pre- and post-correction, and clinical outcome was evaluated as poor, fair, good, and excellent by comparing pre- and post-correction pictures. Different kinds of tests were used to analyze the data. RESULTS: All patients got an improved auricle shape (10 excellent, 2 good, and 4 fair). Multivariate regression analysis showed that CAD type was significantly associated with correction outcome, sex and age were significantly associated with correction outcome for the 11 constructed types of CAD, and age was significantly associated with the correction outcome when we focused on the male constructed auricles. CONCLUSION: 3D-NSC provided a significant nonsurgical clinical treatment for CAD patients, with younger patients getting better clinical outcomes with shorter correction time.

Development of a Survival Prognostic Model for Non-small Cell Lung Cancer.

Lung cancer is a leading cause of cancer-related death, and >80% of lung cancer diagnoses are non-small-cell lung cancer (NSCLC). However, when using current staging and prognostic indices, the prognosis can vary significantly. In the present study, we calculated a prognostic index for predicting overall survival (OS) in NSCLC patients. The data of 545 NSCLC patients were retrospectively reviewed. Univariate and multivariate Cox proportional hazards regression analyses were performed to evaluate the prognostic value of clinicopathological factors. Age (hazard ratio [HR] = 1.25, 95% confidence interval [CI] = 1.02-1.54), TNM stage (III, HR = 1.64, 95% CI = 1.08-2.48; IV, HR = 2.33, 95% CI = 1.48-3.69), lung lobectomy (HR = 1.96, 95% CI = 1.45-2.66), chemotherapy (HR = 1.42, 95% CI = 1.15-1.74), and pretreatment hemoglobin level (HR = 1.61, 95% CI = 1.28-2.02) were independent prognosticators. A prognostic index for NSCLC (PInscl, 0-6 points) was calculated based on age (≥65 years, 1 point), tumor-node-metastasis (TNM) stage (III, 1 point; IV, 2 points), lung lobectomy (no, 1 point), chemotherapy (no, 1 point), and pretreatment hemoglobin level (low, 1 point). In comparison with the "PInscl = 0" subgroup (survival time = 2.71 ± 1.86 years), the "PInscl = 2" subgroup (survival time = 1.86 ± 1.24 years), "PInscl = 3" subgroup (survival time = 1.45 ± 1.07 years), "PInscl = 4" subgroup (survival time = 1.17 ± 1.06 years), "PInscl = 5" subgroup (survival time = 0.81 ± 0.78 years), and "PInscl = 6" subgroup (survival time = 0.65 ± 0.56 years) exhibited significantly shorter survival times. Kaplan-Meier survival analysis showed that patients with higher PInscl scores had poorer OS than those with lower scores (log-rank test: χ2 = 155.82, P < 0.0001). The area under the curve of PInscl for predicting the 1-year OS was 0.73 (95 % CI = 0.69-0.77, P < 0.001), and the PInscl had a better diagnostic performance than the Karnofsky performance status or TNM stage (P < 0.01). In conclusion, the PInscl, which is calculated from age, TNM stage, lung lobectomy, chemotherapy, and pretreatment hemoglobin level, significantly predicted OS in NSCLC patients.

Successful Treatment of Chronic Lower Extremity Ulcers with Allogeneic Platelet-Rich Plasma and Artificial Dermis: A Case Report.

Hydroxyurea is an oral medication associated with painful, nonhealing ulcers, for which there is no effective treatment but permanent discontinuation of hydroxyurea. The authors present a case of leg ulcers that likely occurred as a result of hydroxyurea use in a patient with essential thrombocythemia. Topical treatment with allogeneic platelet-rich plasma and artificial dermis completely healed the leg ulcers without hydroxyurea cessation.

Age-related and gender-stratified differences in the association between high triglyceride and risk of hyperuricemia.

BACKGROUND: Elevated serum uric acid is commonly associated with high triglyceride. However, the relation of triglyceride and hyperuricemia in different gender and age groups is currently not well understood. This study aimed to evaluate age- and gender-related association of high triglyceride with hyperuricemia in a subgroup of Chinese population. METHODS: We retrospectively analyzed physical examination data of 24,438 subjects (12,557 men and 11,881 women) in Kaifeng, China. The alanine aminotransferase, γ-glutamyl transpeptidase, serum creatinine, blood urea nitrogen, total cholesterol, high-density lipoprotein cholesterol, triglyceride and serum uric acid were measured in all subjects. The triglyceride was categorized into < 1.21, 1.21 ~, 1.7 ~, 2.83 ~ and >  5.6 mmol/L subgroups, and odds ratio (OR) and 95% confidence interval (CI) of hyperuricemia were calculated by logistic regression analysis. RESULTS: Univariate and age-adjusted analyses showed that high triglyceride was positively associated with hyperuricemia (p <  0.01). Further age-stratified analysis showed that the positive association was significant in the 20 ~, 30 ~, 40 ~, 50 ~, 60 ~ and 80 ~ age groups in men. In women, no statistically significant was found in 60 ~ and 70 ~ age groups. CONCLUSION: High triglyceride is positively associated with hyperuricemia in both men and women, and this association is age-related, especially in women.

Pretreatment Hemoglobin Level Is an Independent Prognostic Factor in Patients with Lung Adenocarcinoma.

Background/Aim: Few studies have reported the prognostic value of pretreatment hemoglobin levels in patients with lung adenocarcinoma (LA). In the present study, we retrospectively reviewed 306 LA patients for their prognosis associated with the pretreatment hemoglobin levels. Methods: Person-years and case fatality rate (CFR) were calculated from May 2010 to June 2017. Hazard ratio (HR) and 95% confidence intervals (CIs) were estimated using the Cox proportional hazards regression analysis. Survival curves were generated using the Kaplan-Meier analysis. Results: Patients with low pretreatment hemoglobin (LPHb) levels had a higher CFR than did patients with normal pretreatment hemoglobin (NPHb) levels (HR = 1.48, 95% CI = 1.06-2.08, and P=0.023). Overall survival of NPHb patients was significantly higher than that of LPHb patients (P < 0.05). Conclusion: Low pretreatment hemoglobin level was demonstrated to be an independent biomarker for poor prognosis in patients with LA.

Pre-treatment hemoglobin levels are an independent prognostic factor in patients with non-small cell lung cancer.

To date, few studies have reported the prognostic value of pre-treatment hemoglobin levels in patients with non-small cell lung cancer (NSCLC). In the present study, 416 patients with NSCLC were retrospectively reviewed. Univariate Cox proportional hazards regression analysis demonstrated that patients with normal pre-treatment hemoglobin (NPHb) levels had a greater chance of surviving for longer period, than did patients with low pre-treatment hemoglobin (LPHb) levels (HR, 2.05; 95% CI, 1.63-2.57; P<0.001). After adjustment for age, sex, tumor-node-metastasis stage, Karnofsky performance status, lung lobectomy, chemotherapy and radiotherapy, multivariate Cox proportional hazards regression analysis revealed that LPHb was an independent predictor for the poor prognosis of patients with NSCLC (HR, 1.86; 95% CI, 1.47-2.36; P<0.001). Estimation of the cumulative survival revealed that the overall survival of NPHb patients was significantly higher than that for LBHb patients (P<0.05), independent of whether the patients had received lung lobectomy or chemotherapy treatments. In conclusion, low pre-treatment hemoglobin levels were demonstrated to be an independent biomarker for poor prognosis in patients with NSCLC.

Impact of molecular weight in four-branched star vectors with narrow molecular weight distribution on gene delivery efficiency.

A series of star-shaped cationic polymers, termed star vectors (SVs), has been developed as effective nonviral gene delivery carriers. In this study, we separated SVs into several fractions having different molecular weights with very narrow molecular weight distributions in order to examine in detail the influence of the molecular weight of the SVs on the gene transfection efficiency. As a model compound for several types of SVs, 4-branched poly(N,N-dimethylaminopropyl acrylamide) having a molecular weight (M(n)) of approximately 35 kDa and polydispersity of 1.6 was prepared by iniferter-based radical polymerization. The SVs were separated using size-exclusion chromatography to obtain seven fractions having M(n) ranging from 27 kDa to 73 kDa with polydispersity ranging from 1.1 to 1.2. All the fractionated SVs have similar pH of 10.2-10.4 and were able to interact with and condense luciferase-encoding plasmid deoxyribonucleic acid (DNA) to yield SV/DNA polyplexes. A water-soluble tetrazolium-1 (WST) assay showed that all SVs had minimal cellular cytotoxicity under an N/P charge ratio of 10. The critical micellar concentration decreased with an increase in the M(n) of the fractionated SVs; however, the particle size of the polyplexes, exclusion activity of ethidium bromide, and zeta-potential of the polyplexes increased. An in vitro evaluation using COS-1 cells at an N/P ratio of 10 showed that transfection activity increased almost linearly with M(n). The highest transfection activity was obtained for SVs with the highest M(n) (73 kDa), which was over 7 times that for the SVs with the lowest M(n) (27 kDa), the nonfractionated original SV, or PEI standard. The transfection efficiency was more correlated with the amphiphilicity or hydrophobicity of the SVs and the surface potential and condensate density of the polyplexes than with the particle size.

In vitro maturation of "biotube" vascular grafts induced by a 2-day pulsatile flow loading.

Autologous vascular tissues with a small diameter, "biotubes," were developed in vivo using a novel concept in regenerative medicine, "in-body tissue architecture technology." The effect of pulsatile flow in vitro was investigated on the structural and functional properties of the biotubes. Silicone rods (diameter, 3.0 mm; length, 35.0 mm), used as molds, were embedded into dorsal subcutaneous spaces of Wister rats. After 4 weeks, the autologous tubular tissues formed around the rods were harvested. Some tissues were incubated for 2 days under pulsatile flow simulating conditions in the human arteries with small caliber (wall shear stress (WSS), 15.5-77.3 dyn/cm(2); circumferential stress (CS), 0.6-4.5 x 10(5) dyn/cm(2)). Upon flow loading, the sparse, randomly oriented collagen fibers in the biotubes became dense and oriented in the regular circumferential direction. Compliances (beta values) of the control (ca. 30) and flow-loaded (ca. 20) biotubes were equivalent to that of the human coronary arteries and femoral arteries, respectively. Further, upon flow loading, the burst pressure significantly increased from ca. 1000 mmHg to ca. 1800 mmHg, along with the alpha-SMA-positive cell ratio. Pulsatile flow loading in vitro for 2 days could induce biotube maturation in terms of collagen structures and mechanical properties.

Evaluation of self-expandable, FK506-coated, covered stents in canine animal model.

This study aimed to evaluate whether drug coating of the recently developed covered SENDAI stents--self-expandable stents covered with segmented polyurethane (SPU) films--reduces neointimal thickening in animal model. FK506, which is one of the most effective immunosuppressants, was used. Bare stents; non-coated, covered stents; and FK506-coated, covered stents were placed bilaterally in the external iliac arteries of beagle dogs. After 1-month observation period, angiography did not show significant stent-induced stenosis. Histological evaluation revealed a completely endothelialized intravascular lumen and the absence of thrombus formation. The area of the intimal thickening induced by the FK506-coated stents was significantly smaller than that induced by the non-coated stents, whereas it was larger in the case of both the covered stents than that in the case of the bare stent. In conclusion, FK506 treatment of the self-expandable, covered stents was confirmed to effectively inhibit intimal thickening, although the SPU film used for covering functioned as a drug carrier in addition to a scaffold for intimal formation.

Photoinduced cross-linking of star vector for improvement of gene transfer efficiency.

This study aimed to investigate the effect of cross-linking of a cationic nonviral gene carrier on gene expression. As a precursor for photo-cross-linking, a star-shaped, six-branched cationic polymer of poly(N,N-dimethylaminopropylacrylamide) (six-branched star vector, SV), which was previously designed as a gene carrier, was synthesized by iniferter-based living radical polymerization. Upon UV irradiation, the number-average molecular weight (Mn) of the SV increased from ca. 28 kDa to ca. 32 kDa (irradiation time, 180 min) and ca. 46 kDa (240 min) with broadness of the polydispersity due to the coupling reaction between the polymer radicals generated at the terminal ends of each branch of the SVs, resulting in the preparation of cross-linked SVs (CSVs) without the use of any chemical cross-linking agents. Irrespective of cross-linking, all the SVs were able to interact with and condense luciferase-encoding plasmid DNA to yield relatively stable polymer/DNA complexes (polyplexes) of approximate diameter 150 nm with zeta-potential of ca. 20 mV. However, a transfection study using several types of cell lines, HeLa, Hep G2, 293, and COS-1, showed that by cross-linking of SVs the luciferase activity increased drastically. The activity with CSV (Mn=ca. 46 kDa) was increased by at least 1 order of magnitude in the original SV (Mn=ca. 28 kDa), which was several-fold that in the SV with the same molecular weight in all cells. In all SVs, no significant cellular cytotoxicity was observed even at a high charge ratio of 45. The SV-based gene transfection was significantly enhanced by the cross-linking of the SVs.

Development of salmon collagen vascular graft: mechanical and biological properties and preliminary implantation study.

Elastic salmon collagen (SC) vascular grafts were prepared by incubating a mixture of acidic SC solution and a fibrillogenesis-inducing buffer containing a crosslinking agent [water-soluble carbodiimide (WSC)] in a tubular mold at 4 degrees C for 24 h and then at 60 degrees C for 5 min. Subsequently, re-crosslinking in ethanol solution containing WSC was performed. The dimension of the SC grafts was easily controlled by changing the size of the mold used. The compliance (stiffness parameter: beta) and burst strength of the SC grafts (internal diameter, 2 mm; length, 20 mm; and wall thickness, 0.75 mm) that were prepared for implantation were 18.2 and 1434 mmHg, respectively; both these values were comparable with those of native vessels. Upon placement in rat subcutaneous pouches, the SC grafts were gradually biodegraded with little inflammatory reaction. The SC grafts were preliminarily implanted in rat abdominal aortas by using specially designed vascular connecting system. This system was used because the graft exhibited easy tearing and thus inadequate suturability. There was neither aneurysm formation nor graft rupture, but mild thrombus formation was seen within the 4-week observation period. These grafts may be ideal for use in regenerative medicine because we believe that SC would be completely replaced with native vascular tissues after implantation, although further improvement in the mechanical properties of the graft is needed for anastomosis.

Enhancement of star vector-based gene delivery to endothelial cells by addition of RGD-peptide.

This study aimed to investigate the feasibility of using a cationic nonviral gene carrier in endothelial cells for enhancing gene expression by the addition of an integrin-binding RGD peptide. A 4-branched cationic polymer of poly( N,N-dimethylaminopropylacrylamide) (star vector), developed as a gene carrier, could complex with the luciferase-encoding plasmid DNA under a charge ratio of 5 (vector/pDNA) to form polymer/DNA complexes (polyplexes). The addition of the RGD-containing peptide (GRGDNP) to the polyplex solution led to a decrease in the zeta-potential from ca. +30 to +20 mV along with the reduction in the particle size from ca. 300 to 200 nm. Additionally, a marked inhibition of polyplex aggregation was observed, indicating the coating of the polyplex surface with RGD peptides. A transfection study on endothelial cells showed that the luciferase activity increased with the amount of RGD peptides added to the polyplexes and exhibited minimal cellular cytotoxicity. The transfection activity further increased when cyclic RGD peptides (RGDFV) were used; the activity with RGD peptide addition was approximately 8-fold compared to that without RGD peptide addition. Gene delivery to endothelial cells was significantly enhanced by only the addition of RGD peptides to star vector-based polyplexes.

Synthesis and in vitro evaluation of novel star-shaped block copolymers (blocked star vectors) for efficient gene delivery.

Novel 4-branched diblock copolymers consisting of cationic chains as an inner domain and nonionic chains as an outer domain were prepared by iniferter-based living radial polymerization and evaluated as a polymeric transfectant. The cationic polymerization of 3-(N,N-dimethylamino)propyl acrylamide (DMAPAAm) using 1,2,4,5-tetrakis( N,N-diethyldithiocarbamylmethyl)benzene as a 4-functional iniferter followed by the nonionic block polymerization of N,N-dimethylacrylamide (DMAAm) afforded 4-branched diblock copolymers with controlled compositions. By changing the solution or irradiation conditions, 4-branched PDMAPAAms with molecular weights of 10,000, 20,000, and 50,000 were synthesized. In addition, by graft polymerization, PDMAPAAm-PDMAAm blocked copolymers with copolymer composition (unit ratio of DMAAm/DMAPAAm) ranging from 0.18 to 1.0 for each cationic polymer were synthesized. All polymers were shown to interact with and condense plasmid DNA to yield polymer/DNA complexes (polyplexes). A transfection study on COS-1 cells showed that the polyplexes from block copolymers with cationic chain length of approximately 50,000 and a nonionic chain length of 30,000, which were approximately 200 nm in diameter and very stable in aqueous media, had the most efficient luciferase activity with minimal cellular cytotoxicity under a charge ratio of 20 (vector/pDNA). The PDMAPAAm-PDMAAm-blocked, star-shaped polymers are an attractive novel class of nonviral gene delivery systems.