bluuebunny/crossref_metadata_2025 huggingface dataset:
Antitumor effects of novel compound, guttiferone K, on colon cancer by p21Waf1/Cip1‐mediated G0/G1 cell cycle arrest and apoptosis
Authors: Kan Winnie Lai Ting , Yin Chun , Xu Hong Xi , Xu Gang , To Kenneth Kin Wah , Cho Chi Hin , Rudd John Anthony , Lin Ge
Published: June 2012

Low selectivity is one of the major problems of currently used anticancer drugs, therefore, there is a high demand for novel, selective antitumor agents. In this study, the anticancer effects and mechanisms of guttiferone K (GUTK), a novel polyprenylated acylphloroglucinol derivative isolated from Garcinia cowa Roxb., were examined for its development as a novel drug targeting colon cancer. GUTK concentration‐ and time‐dependently reduced the viability of human colon cancer HT‐29 cells (IC50 value 5.39 ± 0.22 μM) without affecting the viability of normal human colon epithelial CCD 841 CoN cells and induced G0/G1 cell cycle arrest in HT‐29 cells by down‐regulating cyclins D1, D3 and cyclin‐dependent kinases 4 and 6, while selectively restoring p21Waf1/Cip1 and p27Kip1 to levels comparable to those observed in normal colon cells, without affecting their levels in normal cells. GUTK (10.0 μM) induced cleavage of PARP, caspases‐3, ‐8 and ‐9 and chromatin condensation to stimulate caspase‐3‐mediated apoptosis. The addition of a JNK inhibitor, SP600125, partially reversed GUTK‐induced caspase‐3 activity, indicating the possible involvement of JNK in GUTK‐induced apoptosis. Furthermore, GUTK (10 mg/kg, i.p.) significantly decreased the tumor volume in a syngeneic colon tumor model when used alone or in combination with 5‐fluorouracil without toxicity to the mice. Immunohistochemical staining of the tumor sections revealed a mechanism involving an increase in cleaved caspase‐3 and a decrease in cell proliferation marker Ki‐67. Our results support GUTK as a promising novel, potent and selective antitumor drug candidate for colon cancer.
Oncolytic Vaccinia virus safely and effectively treats skin tumors in mouse models of xeroderma pigmentosum
Authors: Brun Jan , Mahoney Douglas J. , Le Boeuf Fabrice , Lefebvre Charles , Sanaei Cina A. , Falls Theresa , Mccart J. Andrea , Stojdl David F.
Published: June 2012

Xeroderma pigmentosum (XP) is an orphan autosomal recessive disorder of DNA repair. When exposed to genotoxic stress, XP patients have reduced capacity to remove bulky adducts by nucleotide excision repair and are thus greatly predisposed to cancer. Unfortunately, given the nature of their underlying genetic defect, tumor‐bearing XP patients cannot be treated with conventional DNA damaging therapies. Engineered strains of the poxvirus Vaccinia have been shown to cure cancer in numerous preclinical models, and based on promising Phase I/II clinical trials have recently been approved for late phase evaluation in humans. As poxviruses are nongenotoxic, we investigated whether clinical‐candidate strains of Vaccinia can safely and effectively treat cancers arising from XP. In vitro, Vaccinia virus was highly cytotoxic against tumor‐derived cells from XP patients, on average 10‐ to 100‐fold more so than on nontumor derived control cells from similar patients. In vivo, local or systemic administration of Vaccinia virus led to durable tumor resolution in both xenograft and genetic models of XP. Importantly, Vaccinia virus was well tolerated in the genetic models, which are each null for a critical component of the DNA repair process. Taken together, our data suggest that oncolytic Vaccinia virus may be a safe and effective therapy for cancers arising from XP, and raise the possibility of similar therapeutic potential against tumors that arise in patients with other DNA repair disorders.
Colorectal cancer and RASSF family—A special emphasis on RASSF1A
Authors: Fernandes Maria Sofia , Carneiro Fátima , Oliveira Carla , Seruca Raquel
Published: June 2012

The RAS‐association domain family, commonly referred to as RASSF, is a family of 10 members (RASSF1‐10) implicated in a variety of key biological processes, including cell cycle regulation, apoptosis and microtubule stability. Furthermore, RASSFs have been implicated in tumorigenesis and several family members are now thought to be tumor suppressors. As opposed to the KRAS oncogene, for which mutational activation is frequent in colorectal cancer (CRC), RASSFs are found to be silenced mainly by aberrant promoter methylation. In particular, RASSF1A, RASSF2 and RASSF5 methylation has been associated with CRC development, though the mechanisms of action remain poorly understood. This review focus on the current knowledge of RASSF inactivation in CRC, particularly RASSF1A, and on the implications RASSFs may have as potential biomarkers and for the development of new targeted therapies for CRC.
α‐Catulin downregulates E‐cadherin and promotes melanoma progression and invasion
Authors: Kreiseder Birgit , Orel Lukas , Bujnow Constantin , Buschek Stefan , Pflueger Maren , Schuett Wolfgang , Hundsberger Harald , de Martin Rainer , Wiesner Christoph
Published: June 2012

Metastasis is associated with poor prognosis for melanoma responsible for about 90% of skin cancer‐related mortality. To metastasize, melanoma cells must escape keratinocyte control, invade across the basement membrane and survive in the dermis by resisting apoptosis before they can intravasate into the circulation. α‐Catulin (CTNNAL1) is a cytoplasmic molecule that integrates the crosstalk between nuclear factor‐kappa B and Rho signaling pathways, binds to β‐catenin and increases the level of both α‐catenin and β‐catenin and therefore has potential effects on inflammation, apoptosis and cytoskeletal reorganization. Here, we show that α‐catulin is highly expressed in melanoma cells. Expression of α‐catulin promoted melanoma progression and occurred concomitantly with the downregulation of E‐cadherin and the upregulation of expression of mesenchymal genes such as N‐cadherin, Snail/Slug and the matrix metalloproteinases 2 and 9. Knockdown of α‐catulin promoted adhesion to and inhibited migration away from keratinocytes in an E‐cadherin‐dependent manner and decreased the transmigration through a keratinocyte monolayer, as well as in Transwell assays using collagens, laminin and fibronectin coating. Moreover, knockdown promoted homotypic spheroid formation and concomitantly increased E‐cadherin expression along with downregulation of transcription factors implicated in its repression (Snail/Slug, Twist and ZEB). Consistent with the molecular changes, α‐catulin provoked invasion of melanoma cells in a three‐dimensional culture assay by the upregulation of matrix metalloproteinases 2 and 9 and the activation of ROCK/Rho. As such, α‐catulin may represent a key driver of the metastatic process, implicating potential for therapeutic interference.
Proteomic analysis of oropharyngeal carcinomas reveals novel HPV‐associated biological pathways
Authors: Slebos Robbert J.C. , Jehmlich Nico , Brown Brandee , Yin Zhirong , Chung Christine H. , Yarbrough Wendell G. , Liebler Daniel C.
Published: June 2012

Oropharyngeal carcinoma (OPC) can be classified into two equally prevalent subtypes depending on the presence of human papillomavirus (HPV). Patients with HPV‐positive (HPV+) OPC represent a unique cohort with a distinct tumor biology and clinical behavior compared to HPV‐negative (HPV−) OPC. Genetic studies have demonstrated chromosomal and gene expression changes associated with distinct subclasses of OPC; however, the proteomic consequences of HPV infection are not known. We analyzed sets of ten HPV+ and ten HPV− OPCs and ten normal adult oral epithelia using a standardized global proteomic analysis platform. This analysis yielded a total of 2,653 confidently identified proteins from which we chose 31 proteins on the basis of expression differences between HPV+, HPV− and normal epithelium for targeted protein quantitation. Analysis of differentially expressed proteins by HPV status revealed enrichment of proteins involved in epithelial cell development, keratinization and extracellular matrix organization in HPV− OPC, whereas enrichment of proteins in DNA initiation and replication and cell cycle control was found for HPV+ OPC. Enrichment analysis for transcription factor targets identified transcription factors E2F1 and E2F4 to be highly expressed in HPV+ OPC. We also found high expression of argininosuccinate synthase 1 in HPV+ OPC, suggesting that HPV+ OPC is more dependent on conditionally essential amino acid, arginine, and this was confirmed on a OPC‐specific tissue microarray. These identified proteomic changes reveal novel driving molecular pathways for HPV+ and HPV− OPCs that may be pertinent in therapeutic strategies and outcomes of OPC.
Psychotherapy groups and individual support to enhance mental health and early dyadic interaction among drug‐abusing mothers
Authors: Belt Ritva H. , Flykt Marjo , Punamäki Raija‐Leena , Pajulo Marjukka , Posa Tiina , Tamminen Tuula
Published: June 2012

The purpose of this controlled study was to examine the outcome of psychodynamic mother–infant group psychotherapy (PGT) outpatient intervention for drug‐abusing perinatal mother–infant dyads. PGT comprised 20 to 24 weekly 3‐hr sessions with 3 to 5 months of follow‐up. A comparison intervention group was formed of mothers participating in individually tailored psychosocial support (PSS) lasting, on average, 12 months and providing mother–infant support and practical counseling. We hypothesized that positive changes would occur in maternal drug abuse, mental health, and mother–infant interaction, especially in the PGT group due to its more intensive therapeutic focus. Participants were 26 drug‐abusing dyads in PGT, 25 in PSS, and 50 dyads in a non‐drug‐abusing comparison group. Assessments were pre‐intervention and at 4 and 12 months' follow‐up, including maternal depressive symptoms and mother–child interaction assessed by the Emotional Availability Scales (EA). As hypothesized, in dyadic interaction maternal hostility decreased significantly in the PGT group, and intrusiveness decreased in both intervention groups, but especially in the PTG group. However, both interventions showed a general improvement in the quality of mother–infant interaction. They also succeeded in sustaining high maternal abstinence, treatment retention, and alleviating depressive symptoms. The findings are discussed in relation to preventing negative transgenerational interaction patterns in the high‐risk dyads.
Developmental effects of oral exposure to diethylstilbestrol on mouse placenta
Authors: Nagao Tetsuji , Kagawa Nao , Saito Yoshiaki , Komada Munekazu
Published: June 2012

Placental growth and function are of biological significance in that placental tissue promotes prenatal life and the maintenance of pregnancy. Exposure to synthetic estrogens causes embryonic mortality and placental growth restriction in mice. The aim of the present study was to examine the effects of diethylstilbestrol (DES) on placenta in mice. DES at 1, 5, 10 or 15 µg kg–1 day–1, or 17β‐estradiol (E2) at 50 µg kg–1 day–1, was administered orally to ICR mice on days 4 through to 8 of gestation. Expression of ERα, ERβ, ERRβ or ERRγ mRNA in the junctional or labyrinth zone of the placentas on day 13 was assessed using RT‐PCR, as well as the embrynic mortality, embryonic and placental weight, histological changes of labyrinth and ultrastructural changes of the trophoblast giant cells (TGCs). Embryo mortalities in the DES 10 and 15 µg kg–1 day–1 groups were markedly increased. No significant changes in embryonic and placental weight were observed in any DES‐ or E2‐exposed groups. Expression of ERα mRNA in the junctional zone with male embryos in the 5 µg kg–1 day–1 group was significantly higher than that in the control, whereas expression was not determined in the 15 µg kg–1 day–1 group. Histological observation revealed that the placentas exposed to DES at 10 µg kg–1 day–1 lacked the developing labyrinth. Ultrastructural observation of the TGCs showed poor rough‐surfaced endoplasmic reticulum in the DES 10 µg kg–1 day–1 group. The present data suggest that developmental changes induced by DES may be related to interference with the nutrition and oxygen exchange between mother and embryo or decreased protein synthesis, resulting in a high frequency of embryo mortality. Copyright © 2012 John Wiley & Sons, Ltd.
The effect of grain size on the biocompatibility, cell–materials interface, and mechanical properties of microwave‐sintered bioceramics
Authors: Veljović Djordje , Čolić Miodrag , Kojić Vesna , Bogdanović Gordana , Kojić Zvezdana , Banjac Andrijana , Palcevskis Eriks , Petrović Rada , Janaćković Djordje
Published: June 2012

The effect of decreasing the grain size on the biocompatibility, cell–material interface, and mechanical properties of microwave‐sintered monophase hydroxyapatite bioceramics was investigated in this study. A nanosized stoichiometric hydroxyapatite powder was isostatically pressed at high pressure and sintered in a microwave furnace in order to obtain fine grained dense bioceramics. The samples sintered at 1200°C, with a density near the theoretical one, were composed of micron‐sized grains, while the grain size decreased to 130 nm on decreasing the sintering temperature to 900°C. This decrease in the grain size certainly led to increases in the fracture toughness by much as 54%. An in vitro investigation of biocompatibility with L929 and human MRC‐5 fibroblast cells showed noncytotoxic effects for both types of bioceramics, while the relative cell proliferation rate, cell attachment and metabolic activity of the fibroblasts were improved with decreasing of grain size. An initial in vivo investigation of biocompatibility by the primary cutaneous irritation test showed that both materials exhibited no irritation properties. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A:3059–3070, 2012.
Poly(vinyl alcohol)/collagen/hydroxyapatite hydrogel: Properties and in vitro cellular response
Authors: Song Wei , Markel David C. , Jin Xin , Shi Tong , Ren Weiping
Published: June 2012

The objective of this study was to develop “bone‐like” poly(vinyl alcohol) (PVA)/hydroxyapatite (HA)/type I collagen (Col) hydrogel composites that stimulate adhesion, proliferation, and differentiation of osteoblastic cells. The hydrogel composites were prepared by mixing PVA with nanoscale HA and Col using a physical mixing method. The concentration of the components was optimized during formulation development. PVA/Col/HA hydrogels were characterized for viscoelasticity, degree of swelling, mechanical strength, embedded erythromycin drug release, and cellular response of both osteoblastic MC3T3 cells and RAW 264.7 macrophage cells. Compressive strength tests confirmed that the PVA coating possessed greater elasticity and was mechanically enhanced by the freeze‐thaw treatment. PVA/Col/HA gel is biocompatible and nontoxic to MC3T3 preosteoblasts, and the reinforcement from HA and Col reduced the inflammatory response from macrophages. Our findings demonstrate that PVA composites are biocompatible, and enhance cell adhesion, proliferation, and differentiation in vitro. We propose that PVA/Col/HA hydrogels represent one of the promising implant surface coating matrices for the improvement of implant osseointegration. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A:3071–3079, 2012.
Processing–structure–functional property relationship in organic–inorganic nanostructured scaffolds for bone‐tissue engineering: The response of preosteoblasts
Authors: Depan D. , Misra R. D. K.
Published: June 2012

We elucidate here for the first time the structure–processing–functional property relationship in chitosan (CS)‐based scaffolds, where molecular machinery governing proliferation and growth of osteoblasts is mediated by nanostructured carbon. The interconnected network structure of organic–inorganic scaffolds was obtained by covalent linkage of carboxyl group of functionalized single‐walled carbon nanohorn with the amine group of CS. The molecular‐scale dispersibility of functionalized nanostructured carbon was an important physicochemical factor influencing cellular interactions and biological response. Furthermore, it was beneficial in promoting the biocompatibility and the degradation product of the scaffolds. The hydrophilicity, good water retention ability, and interconnected porous structure of organic–inorganic scaffolds enabled pronounced cell attachment and proliferation and enhanced the stability toward enzymatic degradation. The infiltration of cells and colonization of the pores of the scaffolds and cellular interactions were promoted due to covalent linkage of nanostructured carbon with CS. Additionally, the interconnectivity of porous scaffolds facilitated cells to infiltrate inside the pores of CS‐nanostructured scaffolds, implying that nanostructured carbon merits consideration in tissue engineering. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A:3080–3091, 2012.
Bone tissue, cellular, and molecular responses to titanium implants treated by anodic spark deposition
Authors: Sverzut Alexander T. , de Albuquerque Gustavo C. , Crippa Grasiele E. , Chiesa Roberto , Valle Cinzia Della , de Oliveira Paulo T. , Beloti Marcio M. , Rosa Adalberto L.
Published: June 2012

A myriad of titanium (Ti) surface modifications has been proposed to hasten the osseointegration. In this context, the aim of this study was to perform histomorphometric, cellular, and molecular analyses of the bone tissue grown in close contact with Ti implants treated by anodic spark deposition (ASD‐AK). Acid‐etched (AE) Ti implants either untreated or submitted to ASD‐AK were placed into dog mandibles and retrieved at 3 and 8 weeks. It was noticed that both implants, AE and ASD‐AK, were osseointegrated at 3 and 8 weeks. Histomorphometric analysis showed differences between treatments only for bone‐to‐implant contact, being higher on AE implants. Although not backed by histomorphometric results, gene expression of key bone markers was higher for bone grown in close contact with ASD‐AK and for cells harvested from these fragments and cultured until subconfluence. Cell proliferation at days 7 and 10 and alkaline phosphatase activity at day 10 was higher on AE surfaces. No statistical significant difference was noticed for extracellular matrix mineralization at 17 days. Our results have shown that the Ti fixtures treated by ASD‐AK allowedin vivoosseointegration and induced higher expression of key markers of osteoblast phenotype, suggesting that this surface treatment could be considered to produce implants for clinical applications. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A:3092–3098, 2012.
Platelet‐rich plasma loaded in situ‐formed hydrogel enhances hyaline cartilage regeneration by CB1 upregulation
Authors: Lee Hye‐Rim , Park Kyung Min , Joung Yoon Ki , Park Ki Dong , Do Sun Hee
Published: June 2012

The efficacy of three‐dimensional (3D) culture on the proliferation and maturation of chondrocytes seeded into a hydrogel scaffold was assessed. Three types of hydrogel were prepared for the 3D culture of primary isolated chondrocytes. Chondrocyte proliferation was assessed using a live/dead viability/cytotoxicity assay and semiquantitative RT‐PCR after 3D culture in hydrogel. Cylindrical defects in the center of rat xyphoids were used for the implantation of platelet‐rich plasma (PRP)/hydrogel composites. Rats were killed at day 7 postoperatively and evaluated histochemically and immunohistologically. Xyphoid chondrocytes proliferated well with time in hydrogels. In the PRP‐containing hydrogels, xyphoid defects displayed early formation of chondroid matrix with massive peripheral infiltration of spindle cells. These results were consistent with Safranin‐O staining for proteoglycans and immunohistochemistry for type II collagen. Gene expression analyses in vitro revealed aggrecan, type II collagen, and ChM‐1 and CB1 upregulation by PRP/hydrogel. PRP/hydrogel provided a suitable environment for hyaline cartilaginous regeneration, leading to anti‐inflammation by significant increase of CB1 and inhibiting vascular ingrowth via considerable upregulation of ChM‐1. The results provide a valuable reference for the clinical application of hydrogel scaffolds for hyaline cartilage regeneration, as well as the use of autologous PRP to improve cellular proliferation and maturation of xyphoid repair. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A:3099–3107, 2012.
Directed osteogenic differentiation of human mesenchymal stem/precursor cells on silicate substituted calcium phosphate
Authors: Cameron Kate , Travers Paul , Chander Chaman , Buckland Tom , Campion Charlie , Noble Brendon
Published: June 2012

Insufficient, underactive, or inappropriate osteoblast function results in serious clinical conditions such as osteoporosis, osteogenesis imperfecta and fracture nonunion and therefore the control of osteogenesis is a medical priority.In vitromesenchymal stem cells (MSCs) can be directed to form osteoblasts through the addition of soluble factors such as β‐glycerophosphate, ascorbic acid, and dexamethasone; however this is unlikely to be practical in the clinical setting. An alternative approach would be to use a scaffold or matrix engineered to provide cues for differentiation without the need for soluble factors. Here we describe studies using Silicate‐substituted calcium phosphate (Si‐CaP) and unmodified hydroxyapatite (HA) to test whether these materials are capable of promoting osteogenic differentiation of MSCs in the absence of soluble factors. Si‐CaP supported attachment and proliferation of MSCs and induced osteogenesis to a greater extent than HA, as evidenced through upregulation of the osteoblast‐related genes:Runx2(1.2 fold),Col1a1(2 fold),Pth1r(1.5 fold), andBglap(1.7 fold)Dmp1(1.1 fold), respectively. Osteogenic‐associated proteins, alkaline phosphatase (1.4 fold), RUNX2, COL1A1, and BGLAP, were also upregulated and there was an increased production of mineralized bone matrix (1.75 fold), as detected by the Von Kossa Assay. These data indicate that inorganic substrates are capable of directing the differentiation programme of stem cells in the absence of known chemical drivers and therefore may provide the basis for bone repair in the clinical setting. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A:13–22, 2013.
Architectural characterization of organotypic cultures of H400 and primary rat keratinocytes
Authors: Khan Erum , Shelton Richard M. , Cooper Paul R. , Hamburger John , Landini Gabriel
Published: June 2012

Organotypic epithelial structures can be cultured using primary or immortalized keratinocytes. However, there has been little detailed quantitative histological characterization of such cultures in comparison with normal mucosal architecture. The aim of this study is to identify morphological markers of tissue architecture that can be used to monitor tissue structure, maturation, and differentiation and to enable quantitative comparison of organotypic cultures (OCs) with normal oral mucosa. OCs of oral keratinocytes [immortalized H400 or primary rat keratinocytes (PRKs)] were generated using the three scaffolds of de‐epidermalized dermis (DED), polyethylene terephthalate (PET), and collagen gels for up to 14 days. Cultures and normal epithelium were analyzed immunohistochemically and by using the semi‐quantitative reverse transcriptase polymerase chain reaction (sq‐RT‐PCR) for E‐cadherin, desmoglein‐3, plakophilin, involucrin, cytokeratins‐1, ‐5, ‐6, ‐10, ‐13, and Ki67. The epithelial thickness of OCs was measured in stained sections using image processing. Histological analysis revealed that air–liquid interface (ALI) cultures generated stratified organotypic epithelial structures by 14‐days. The final thickness of these cultures as well as the degree of maturation/stratification (including stratum corneum formation) varied significantly depending on the scaffold used. For certain scaffolds, the immunohistochemical profiles obtained recapitulated those of normal oral epithelium indicating comparable in vitro differentiation and proliferation. In conclusion, quantitative microscopy approaches enabled unbiased architectural characterization of OCs. The scaffold materials used in the present study (DED, collagen type‐I and PET) differentially influenced cell behavior in OCs of oral epithelia. H400 and PRK OCs on DED at the ALI demonstrated similar characteristics in terms of gene expression and protein distribution to the normal tissue architecture. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A 100A:3227–3238, 2012.
In vitro degradation, biocompatibility, and in vivo osteogenesis of poly(lactic‐co‐glycolic acid)/calcium phosphate cement scaffold with unidirectional lamellar pore structure
Authors: He Fupo , Ye Jiandong
Published: June 2012

The aim of this study was to investigate the in vitro degradation, cytocompatibility, and in vivo osteogenesis of poly(lactic‐co‐glycolic acid) (PLGA)/calcium phosphate cement (CPC) scaffold with unidirectional lamellar pore structure. CPC‐based scaffold was fabricated by unidirectional freeze casting, and PLGA was used to improve the mechanical properties of the CPC‐based scaffold, which covered the surface of the pore wall as coating. The in vitro degradation results demonstrated that the PLGA/CPC scaffold had good degradability. The degradation of PLGA film on the surface of the scaffold made the CPC matrix exposed, which facilitated cell response and osteogenesis. Rat bone mesenchymal stem cells (rMSCs) were seeded on the PLGA/CPC composite scaffold. Cell viability, proliferation, and differentiation on the PLGA/CPC composite scaffold were evaluated. The results showed that viable rMSCs attached on the surface of pore wall gradually penetrated into the internal pores of the scaffold as prolongation of culture time. In addition, the rMSCs seeded on the scaffold exhibited good proliferation and growing alkaline phosphatase activity. The scaffold was implanted in the defects in distal end of femora of New Zealand white rabbits. Histological evaluation indicated that the PLGA/CPC scaffold with unidirectional lamellar pore structure had good biocompatibility and effective osteogenesis. These results suggest PLGA/CPC composite scaffold with unidirectional lamellar pore structure is a promising scaffold for bone tissue engineering. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A 100A:3239–3250, 2012.
The in vitro and in vivo biocompatibility evaluation of heparin–poly(ε‐caprolactone) conjugate for vascular tissue engineering scaffolds
Authors: Ye Lin , Wu Xin , Duan Hong‐Yong , Geng Xue , Chen Bing , Gu Yong‐Quan , Zhang Ai‐Ying , Zhang Jian , Feng Zeng‐Guo
Published: June 2012

Poly(ε‐caprolactone) (PCL) was conjugated with heparin and fabricated into nonwoven tubular scaffold by electrospinning. The dynamic contact angle analysis revealed the hydrophilicity improvement due to heparin concentrating on the conjugate surface. The microbicinchoninic acid and quartz crystal microbalance measurements implied that the conjugate can significantly reduce the absorption of plasma protein, such as albumin and fibrinogen, indicative of the good blood biocompatibility. As evidenced by Enzyme Linked Immunosorbent Assay, the electrospun conjugate scaffolds possessed a higher loading capability of vascular endothelial growth factor (VEGF) than that of the blank PCL in aqueous solution via static interaction. The viability of loaded VEGF was evaluated by cell culture and adhesion tests. The amount and morphology of cells were substantially improved after VEGF was loaded into scaffolds exhibiting excellent cell biocompatibility. To assess the in vivo biocompatibility, a tubular scaffold (L = 4 cm, D = 2 mm) was transplanted into dog's femoral artery. The scaffold patency was inspected by carotid artery angiography 4 weeks after implantation. The explanted scaffold was also investigated by histological analysis including hematoxyline eosin, Millere Masson (collagen and elastin), and von Kossa (calcium) stain. Furthermore, von Willebrand factor immunohistochemical stain was performed to examine the formation of endothelial layer. The conjugate shows the potential to be used as scaffold materials in vascular tissue engineering. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A 100A:3251–3258, 2012.
Biomimetic coating on bioactive glass‐derived scaffolds mimicking bone tissue
Authors: Bellucci D. , Sola A. , Gentile P. , Ciardelli G. , Cannillo V.
Published: June 2012

Bioceramic “shell” scaffolds, with a morphology resembling the cancellous bone microstructure, have been recently obtained by means of a new protocol, developed with the aim to overcome the limits of the conventional foam replication technique. Because of their original microstructure, the new samples combine high porosity, permeability, and manageability. In this study, for the first time, the novel bioactive glass shell scaffolds are provided with a gelatin‐based biomimetic coating to realize hybrid implants which mimic the complex morphology and structure of bone tissue. Moreover, the presence of the coating completely preserves the in vitro bioactivity of the bioactive glass samples, whose surfaces are converted into hydroxyapatite after a few days of immersion in a simulated body fluid solution (SBF). © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A 100A:3251–3258, 2012.
Evaluation of bone regeneration, angiogenesis, and hydroxyapatite conversion in critical‐sized rat calvarial defects implanted with bioactive glass scaffolds
Authors: Bi Lianxiang , Jung Steve , Day Delbert , Neidig Katie , Dusevich Vladimir , Eick David , Bonewald Lynda
Published: June 2012

Bioactive glasses are biocompatible materials that convert to hydroxyapatite in vivo, and potentially support bone formation, but have mainly been available in particulate and not scaffold form. In this study, borosilicate and borate bioactive glass scaffolds were evaluated in critical‐sized rat calvarial defects. Twelve‐week‐old rats were implanted with 45S5 silicate glass particles and scaffolds of 1393 silicate, 1393B1 borosilicate, and 1393B3 borate glass. After 12 weeks, the defects were harvested, stained with hematoxylin and eosin to evaluate bone regeneration, Periodic Acid Schiff to quantitate blood vessel area, and von Kossa and backscatter SEM to estimate newly mineralized bone and hydroxyapatite conversion of bioactive glasses. The amount of new bone was 12.4% for 45S5, 8.5% for 1393, 9.7% for 1393B1, and 14.9% for 1393B3 (*p = 0.04; cf. 1393 and 1393B1). Blood vessel area was significantly higher (p = 0.009) with 45S5 (3.8%), with no differences among 1393 (2.0%), 1393B1 (2.4%), or 1393B3 (2.2%). Percent von Kossa‐positive area was 18.7% for 45S5, 25.4% for 1393, 29.5% for 1393B1, and 30.1% for 1393B3, significantly higher (p = 0.014) in 1393B1 and 1393B3 glasses than in 45S5. 45S5 and 1393B3 converted completely to HA in vivo. The 1393B3 glass provided greater bone formation and may be more promising for bone defect repair due to its capacity to be molded into scaffolds. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A 100A:3267–3275, 2012.
Channeled scaffolds implanted in adult rat brain
Authors: Martínez‐Ramos Cristina , Vallés‐Lluch Ana , Verdugo José Manuel García , Ribelles José Luis Gómez , Barcia Albacar Juan Antonio , Orts Amparo Baiget , Soria López José Miguel , Pradas Manuel Monleón
Published: June 2012

Scaffolds with aligned channels based on acrylate copolymers, which had previously demonstrated good compatibility with neural progenitor cells were studied as colonizable structures bothin vitrowith neural progenitor cells andin vivo, implanted without cells in two different locations, in the cortical plate of adult rat brains and close to the subventricular zone.In vitro, neuroprogenitors colonize the scaffold and differentiate into neurons and glia within its channels. When implantedin vivoimmunohistochemical analysis by confocal microscopy for neural and endothelial cells markers demonstrated that the scaffolds maintained continuity with the surrounding neural tissue and were colonized by GFAP‐positive cells and, in the case of scaffolds implanted in contact with the subventricular zone, by neurons. Local angiogenesis was evidenced in the interior of the scaffolds' pores. New axons and neural cells from the adult neural niche abundantly colonized the biomaterial's inner structure after 2 months, and minimal scar formation was manifest around the implant. These findings indicate the biocompatibility of the polymeric material with the brain tissue and open possibilities to further studies on the relevance of factors such as scaffold structure, scaffold seeding and scaffold placement for their possible use in regenerative strategies in the central nervous system. The development of neural interfaces with minimized glial scar and improved tissue compatibility of the implants may also benefit from these results. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A 100A:3276–3286, 2012.
Preparation and in vivo degradation of controlled biodegradability of electrospun silk fibroin nanofiber mats
Authors: Kim Ji Heui , Park Chan Hum , Lee Ok‐Joo , Lee Jung‐Min , Kim Jong Wook , Park Young Hwan , Ki Chang Seok
Published: June 2012

Controlled biodegradability of biomaterials is very important because different functionality and durability are required for various purposes and for specific tissues and organs. From this point of view, silk‐based biomaterials have poor usability because of uncontrollable degradability, even though silk fibroin (SF) is highly biocompatible and a number of studies on silk biomaterials have been published to date. In this study, we prepared SF nanofiber mats that were recrystallized in different ways. These mats were fabricated by electrospinning with ethanol/propanol mixtures of various blend ratios, and their biodegradabilities in vitro and in vivo were evaluated using rats. As a result, we can suggest an established method to modulate the degradability of SF nanofibrous materials based on long‐term (12 months) observations. In particular, we elucidated how the SF nanofibers are degraded and incorporated with surrounding tissue by observation of fluorescein isothiocyanate–labeled SF nanofiber in vivo. Our findings suggest a method for controlling the degradation rate of SF for medical applications. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A 100A:3287–3295, 2012.
Controlled release niosome embedded chitosan system: Effect of crosslink mesh dimensions on drug release
Authors: Williams Eva Christabel , Toomey Ryan , Alcantar Norma
Published: June 2012

We report on a model chemotherapy drug delivery system comprising nonionic surfactant vesicles (niosomes) packaged within a temperature‐sensitive chitosan network. This smart packaging, or package‐within‐a package system, provides two distinct advantages. First, the gel prevents circulation of the niosomes and maintains delivery in the vicinity of a tumor. Second, the chitosan network protects the niosomes against fluctuations in tonicity, which affects delivery rates. Tonicity is the sum of the concentrations of the solutes which have the capacity to exert an osmotic force across the membrane. All release rate experiments were conducted with 5,6‐carboxyfluorescein, a fluorescent dye. Release rates were monitored from both bare niosomes alone and niosome‐embedded, chitosan networks. It was observed that chitosan networks prolonged delivery from 100 h to 55 days in low ionic strength environment and pH conditions similar to a tumor site. The primary effect of chitosan is to add control on release time and dosage, and stabilize the niosomes through a high ionic strength surrounding that prevents uncontrolled bursting of the niosomes. Secondary factors include crosslink density of the chitosan network, molecular weight of the individual chitosan polymers, dye concentration within the niosomes, and the number density of niosomes packaged within the chitosan network. Each of these factors can be altered to fine‐tune release rates. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A 100A:3296–3303, 2012.
Volumetric bone regenerative efficacy of biphasic calcium phosphate‐collagen composite block loaded with rhBMP‐2 in vertical bone augmentation model of a rabbit calvarium
Authors: Kim Jin‐Woo , Jeong Im‐Hee , Lee Kwang‐Il , Jung Ui‐Won , Kim Chang‐Sung , Choi Seong‐Ho , Cho Kyoo‐Sung , Yun Jeong‐Ho
Published: June 2012

Block‐type biphasic calcium phosphate (BCP) carriers are more effective at delivering recombinant human bone morphogenetic protein‐2 (rhBMP‐2) in various clinical situations than are particle‐type carriers, due to their potential for highly successful three‐dimensional bone regeneration. The aim of this study was to confirm the bone‐regenerative capabilities of three‐dimensional BCP blocks with a low hydroxyapatite/β‐tricalcium phosphate ratio (20/80) combined with collagen (10% wt) as an rhBMP‐2 delivery system in a craniofacial vertical bone augmentation model. BCP blocks and BCP‐collagen blocks (with average macropore sizes of 296 and 390 μm, respectively) with or without rhBMP‐2 were fixed with osteosynthesis screws to the calvarial surface of rabbits. After 8 weeks, histologic and histomorphometric analyses were performed to evaluate the resulting new bone area, augmented area, bone density, and degree of integration. The area of new bone was significantly greater in specimens containing rhBMP‐2 than in the control group (p < 0.05). Moreover, the area fractions of newly formed bone within the augmented area and a degree of integration between the regenerative bone and the calvarium were both significantly greater in the BCP‐collagen/rhBMP‐2 group than in the BCP/rhBMP‐2 group (p < 0.05), whereas the two carrier systems exhibited similar rhBMP‐2 release profiles, with sustained and linear release. The BCP and BCP/rhBMP‐2 blocks exhibited excellent structural integrity, with large fragments of residual ceramic. In conclusion, the BCP‐collagen composite block exhibited enhanced osteoinductive potential and could be a good candidate as a carrier of rhBMP‐2 due to its characteristics of favorable volumetric stability, ease of handling, and excellent remodeling properties. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A:3304–3313, 2012.
Promotion of pro‐osteogenic responses by a bioactive ceramic coating
Authors: Aniket  , Young Amy , Marriott Ian , El‐Ghannam Ahmed
Published: June 2012

The objective of this study was to analyze the responses of bone‐forming osteoblasts to Ti‐6Al‐4V implant material coated with silica‐calcium phosphate nanocomposite (SCPC50). Osteoblast differentiation at the interface with SCPC50‐coated Ti‐6Al‐4V was correlated to the adsorption of high amount of serum proteins, high surface affinity to fibronectin, Ca uptake from and P and Si release into the medium. SCPC50‐coated Ti‐6Al‐4V adsorbed significantly more serum protein (p< 0.05) than control uncoated substrates. Moreover, Western blot analysis showed that the SCPC50 coating had a high affinity for serum fibronectin. Protein conformation analyses by FTIR showed that the ratio of the area under the peak for amide I/amide II bands was significantly higher (p< 0.05) on the surface of SCPC50‐coated substrates than that on the surface of the control uncoated substrates. Moreover, ICP − OES analyses indicated that SCPC50‐coated substrates withdrew Ca ions from, and released P and Si ions into, the tissue culture medium, respectively. In conjunction with the favorable protein adsorption and modifications in medium composition, MC3T3‐E1 osteoblast‐like cells attached to SCPC50‐coated substrates expressed 10‐fold higher level of mRNA encoding osteocalcin and had significantly higher production of osteopontin and osteocalcin proteins than cells attached to the uncoated Ti‐6A1‐4V substrates. In addition, osteoblast‐like cells attached to the SCPC50‐coated substrates produced significantly lower levels of the inflammatory and osteoclastogenic cytokines, IL‐6, IL‐12p40, and RANKL than those attached to uncoated Ti‐6Al‐4V substrates. These results suggest that SCPC50 coating could enhance bone integration with orthopedic and maxillofacial implants while minimizing the induction of inflammatory bone cell responses. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A:3314–3325, 2012.
Osteocompatibility evaluation of poly(glycine ethyl ester‐co‐alanine ethyl ester)phosphazene with honeycomb‐patterned surface topography
Authors: Duan Shun , Yang Xiaoping , Mao Jifu , Qi Bing , Cai Qing , Shen Hong , Yang Fei , Deng Xuliang , Wang Shenguo
Published: June 2012

Biodegradable amino acid ester‐substituted polyphosphazenes are unique biomaterials for tissue engineering. Considering the surface properties as topography and chemical composition having vital roles in regulating cellular response, in this study, a kind of micropatterned polyphosphazene films were prepared and subjected to osteoblasts culture. Briefly, poly(glycine ethyl ester‐co‐alanine ethyl ester)phosphazene (PGAP) was synthesized, and its solution in chloroform was cast under high (80%) or low (20%) environmental humidity. Honeycomb‐patterned or flat PGAP films were resulted. By analyzing with scanning electron microscope, atomic force microscope, X‐ray photoelectron spectroscope, and water contact angle measurement, the honeycomb‐patterned PGAP films demonstrated higher surface roughness, phosphorous and nitrogen content, and hydrophilicity than the flat one. Although the initial cell attachment and proliferation on PGAP films were inferior to those on conventional poly(lactic‐co‐glycolic acid) films, P‐containing PGAP was a sort of bone‐binding bioactive polymer. With these alternations, honeycomb‐patterned PGAP films had accordingly enhanced protein adsorption and apatite deposition in simulated body fluid and showed great advantages in promoting osteogenous differentiation. The results suggested a potential way to make polyphosphazenes as good choices for bone tissue regeneration by increasing their surface roughness and phosphorous content. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.
Mechanical evaluation and cell response of woven polyetheretherketone scaffolds
Authors: Edwards S. L. , Werkmeister J. A.
Published: June 2012

Polyetheretherketone (PEEK) is a high performance polymer, with high melting temperature and high resistance to wear. PEEK biomedical devices are typically manufactured to produce nonflexible structures. In this study, we fabricated flexible PEEK scaffolds from multifilament and monofilament yarns, using weaving technologies. Scaffolds were compared for structural and mechanical properties, and assessed for in vitro biological response to L929 mouse fibroblast cells. PEEK scaffolds were found to support fibroblast cell attachment and proliferation, with similar cell numbers to a polyethylene terephthalate scaffold. The large pores (261–280 μm) of the monofilament scaffold prevented pore coverage by cells, confining cells to filaments, whereas the smaller pores (81–100 μm) of the multifilament scaffold permitted partial pore coverage. Poor cell adhesion, due to large filament curvature angles, created a checkered pattern on the woven surface, a previously undocumented phenomenon. The multifilament scaffold was found to be lighter, thinner, and less porous, with better mechanical properties (load at break: 657 N, elastic recovery: 66%, burst strength: 492 N) than the monofilament scaffold (load at break: 534 N, elastic recovery: 30%, burst strength: 401 N). Results indicate that flexible PEEK woven structures may find application as tissue engineering scaffolds, particularly for engineering soft tissues. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A:3326–3331, 2012.
Chondrogenesis of human bone marrow mesenchymal cells by transforming growth factors β1 through cell shape changes on controlled biomaterials
Authors: Shao Hung‐Jen , Ho Chia‐Chi , Lee Yu‐Tsang , Chen Chiang‐Sang , Wang Jyh‐Horng , Young Tai‐Horng
Published: June 2012

The phenotypic responses of human bone marrow mesenchymal cells (hBMSCs) on different ratio of chitosan/polycaprolactone (PCL) blends were investigated in this study. The results showed that hBMSCs existed different morphology on chitosan/PCL blends due to the different adhesion characteristic of cell on neat PCL and neat chitosan. Interestingly, comparing to hBMSCs on neat PCL, hBMSCs aggregated to form spheroid and to express ascendant trend of transforming growth factor β1, collagen type II, collagen type X, and Sox9 mRNA on the chitosan/PCL blended substrates with the decrease of PCL content. To confirm chondrogenesis of hBMSCs with spheroid on test substrates, Alcian Blue and Safranin O staining were used to detect the cartilaginous extracellular matrix (ECM). It revealed hBMSCs with spheroid on neat chitosan and 10 wt % PCL did turn to chondrogenic differentiation and synthesize cartilaginous ECM. Therefore, these findings provided new insights into the role of chitosan/PCL blended material could mediate the endogenous gene expression of hBMSCs to alter the phenotypic behavior through mediating the cell shape. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A:3344–3352, 2012.
Modeling of drug release from biodegradable triple‐layered microparticles
Authors: Lee Wei Li , Shi Wen‐Xiong , Low Zheng Yang , Li Shuzhou , Loo Say Chye Joachim
Published: June 2012

Numerous models that predict drug release from nonerodible reservoir‐membrane sphere systems have been presented. Most of these models cater only to a phase of drug release from a constant reservoir. All these models, however, are not applicable to drug release from biodegradable triple‐layered microparticle system, in which the drug‐loaded core (reservoir) is surrounded by nondrug holding outer layers (membrane). In this article, a mathematical model was developed for ibuprofen release from degradable triple‐layered microparticles made of poly(D,L‐lactide‐co‐glycolide, 50:50) (PLGA), poly(L‐lactide) (PLLA), and poly(ethylene‐co‐vinyl acetate, 40 wt % vinyl acetate) (EVA), where ibuprofen was localized within the nonconstant reservoir (EVA core). The model postulated that the drug release through the bulk‐degrading PLLA and PLGA layers consisted of two mechanisms: simple diffusional release followed by a degradation‐controlled release through a rate‐limiting membrane. The proposed model showed very good match with the experimental data of release from microparticles of various layer thicknesses and particle sizes. The underlying drug release mechanisms are dictated by three parameters determined by the model, including constant characteristic of diffusion, end time point of simple diffusion‐controlled release and partition coefficient of drug. The presented model is effective for understanding the drug release mechanisms and for the design of this type of dosage form. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A:3353–3362, 2012.
Bone cement/layered double hydroxide nanocomposites as potential biomaterials for joint implant
Authors: Kapusetti Govinda , Misra Nira , Singh Vakil , Kushwaha R. K. , Maiti Pralay
Published: June 2012

Poly(methyl methacrylate)‐based bone cement and layered double hydroxide (LDH) nanocomposites have been used as a grouting material for total joint arthroplasty. Few weight percentage of nanoLDH was uniformly dispersed in the bone cement matrix to have adequate interaction with matrix polymer. Mechanical strength, stiffness, toughness, and fatigue resistance of the nanocomposites are found to be higher than that of pure bone cement. Nanocomposites are thermally stable as compared to pristine bone cement. Direct mixing of the nanoLDH without any organic solvent makes these nanocomposites biocompatible. Biocompatibility was evaluated and compared with that of commercial bone cement by measuring hydrophilic nature, hemolysis assay, thrombosis assay, and deposition of apatite in simulated body fluid immersion. Finally, the viability of human osteoblast cells on the above developed nanocomposites was testified for actual biocompatibility. The experiment showed better cell growth in nanocomposites as compared to pure bone cement. Thus, these nanocomposites are found to be better grouting material than bone cement. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A:3363–3373, 2012.