Gelatin nanoparticles as gene carriers for transgenic chicken applications

To develop a safe and effective nonviral gene delivery system for transgenic chicken manipulation, we developed gelatin nanocarriers using a reporter plasmid (pEGFP-C1; enhanced green fluorescence protein, EGFP) that expressed EGFP. pEGFP-C1-containing gelatin nanoparticles (GP/pEGFP) were prepared using a water-ethanol solvent displacement method and characterized by size, surface charge, DNA loading, and DNA protection ability. For gene delivery, pEGFP-C1 was stably and efficiently encapsulated in GPs that were approximately 300 nm in diameter with a slight negative surface charge, which was prepared from gelatin solution at pH 8.0. Approximately, 85% of the plasmid DNA was encapsulated in the GPs. Electrophoresis results showed that the GPs provided protection against DNase I digestion. We used the GP/pEGFP as a vector to transfect cells and chicken embryos. The vector was nontoxic to cells, and GFP expression was effectively expressed 24 h after HeLa cell transfection. Direct injection was adapted for vector transport to the chicken embryo; injection in the area opaca (Ao) of the egg resulted in the highest hatching rate without affecting embryo development. GFP gene expression in embryo sections was observed 4 days after injection. The results of this study demonstrate that GPs are a suitable nonviral vector for delivering exogenous genes for transgenic chicken manipulation.

In vitro studies of composite bone filler based on poly(propylene fumarate) and biphasic α-tricalcium phosphate/hydroxyapatite ceramic powder

While many different filler materials have been applied in vertebral augmentation procedures, none is perfect in all biomechanical and biological characteristics. To minimize possible shortages, we synthesized a new biodegradable, injectable, and premixed composite made from poly(propylene fumarate) (PPF) and biphasic α-tricalcium phosphate (α-TCP)/hydroxyapatite (HAP) ceramics powder and evaluated the material properties of the compound in vitro. We mixed the PPF cross-linked by N-vinyl pyrrolidinone and biphasic α-TCP/HAP powder in different ratios with benzoyl peroxide as an initiator. The setting time and temperature were recorded, although they could be manipulated by modulating the concentrations of hydroquinone and N,N-dimethyl-p-toluidine. Degradation, cytocompatibility, mechanical properties, and radiopacity were analyzed after the composites were cured by a cylindrical shape. We also compared the study materials with poly(methyl methacrylate) (PMMA) and PPF with pure HAP particles. Results showed that lower temperature during curing process (38-44°C), sufficient initial mechanical compressive fracture strength (61.1±3.7MPa), and gradual degradation were observed in the newly developed bone filler. Radiopacity in Hounsfield units was similar to PMMA as determined by computed tomography scan. Both pH value variation and cytotoxicity were within biological tolerable limits based on the biocompatibility tests. Mixtures with 70% α-TCP/HAP powder were superior to other groups. This study indicated that a composite of PPF and biphasic α-TCP/HAP powder is a promising, premixed, injectable biodegradable filler and that a mixture containing 70% α-TCP/HAP exhibits the best properties.

Tissue engineering-based cartilage repair with mesenchymal stem cells in a porcine model

This in vivo pilot study explored the use of mesenchymal stem cell (MSC) containing tissue engineering constructs in repair of osteochondral defects. Osteochondral defects were created in the medial condyles of both knees of 16 miniature pigs. One joint received a cell/collagen tissue engineering construct with or without pretreatment with transforming growth factor β (TGF-β) and the other joint from the same pig received no treatment or the gel scaffold only. Six months after surgery, in knees with no treatment, all defects showed contracted craters; in those treated with the gel scaffold alone, six showed a smooth gross surface, one a hypertrophic surface, and one a contracted crater; in those with undifferentiated MSCs, five defects had smooth, fully repaired surfaces or partially repaired surfaces, and one defect poor repair; in those with TGF-β-induced differentiated MSCs, seven defects had smooth, fully repaired surfaces or partially repaired surfaces, and three defects showed poor repair. In Pineda score grading, the group with undifferentiated MSC, but not the group with TGF-β-induced differentiated MSCs, had significantly lower subchondral, cell morphology, and total scores than the groups with no or gel-only treatment. The compressive stiffness was larger in cartilage without surgical treatment than the treated area within each group. In conclusion, this preliminary pilot study suggests that using undifferentiated MSCs might be a better approach than using TGF-β-induced differentiated MSCs for in vivo tissue engineered treatment of osteochondral defects.

Cartilage regeneration in SCID mice using a highly organized three-dimensional alginate scaffold

Tissue engineering for cartilage regeneration provides an alternative to surgery for degenerative osteoarthritis. Recently, a highly organized three-dimensional (3D) alginate scaffold was prepared using a microfluidic device; this scaffold is effective for chondrocyte culture in vitro. The performance of this scaffold was further demonstrated; an alginate scaffold seeded with porcine chondrocytes was implanted in the dorsal subcutaneous site of SCID mice. The recipients were sacrificed at 2, 4, and 6 weeks after transplantation. The grafted implants retrieved from the subcutaneous site were analyzed with histologic examinations. Real-time PCR was used to identify the gene expression patterns of the chondrocytes. The hematoxylin and eosin staining showed that the chondrocytes survived normally in SCID mice; cartilage-like structures were formed after 4 weeks implantation. Immunohistochemical staining revealed cells secreted type II collagen, produced glycosaminoglycans (proved by alcian blue stain), and maintained the expression of S-100. On the other hand, the cells were negative for type I and type X collagen staining. PCR showed that the mRNA expressions of aggrecan and type II collagen were up-regulated at weeks two and four, while type I and type X collagen were down-regulated during the study period. In summary, this highly organized 3D alginate scaffold provided a suitable environment and maintained functional phenotypes for chondrocytes in this animal study.

A highly organized three-dimensional alginate scaffold for cartilage tissue engineering prepared by microfluidic technology

Osteoarthritis is a degenerative disease and frequently involves the knee, hip and phalangeal joints. Current treatments used in small cartilage defects including multiple drilling, abrasion arthroplasty, mosaicplasty, and autogenous chondrocyte transplantation, however, there are problems needed to be solved. The standard treatment for severe osteoarthritis is total joint arthroplasty. The disadvantages of this surgery are the possibility of implant loosening. Therefore, tissue engineering for cartilage regeneration has become a promising topic. We have developed a new method to produce a highly organized single polymer (alginate) scaffold using microfluidic device. Scanning electron microscope and confocal fluoroscope examinations showed that the scaffold has a regular interconnected porous structure in the scale of 250 μm and high porosity. The scaffold is effective in chondrocyte culture; the cell viability test (WST-1 assay), cell toxicity (lactate dehydrogenase assay), cell survival rate, extracellular matrix production (glycosaminoglycans contents), cell proliferation (DNA quantification), and gene expression (real-time PCR) all revealed good results for chondrocyte culture. The chondrocytes can maintain normal phenotypes, highly express aggrecan and type II collagen, and secrete a great deal of extracellular matrix when seeded in the alginate scaffold. This study demonstrated that a highly organized alginate scaffold can be prepared with an economical microfluidic device, and this scaffold is effective in cartilage tissue engineering.

Hyaluronan up-regulates IL-10 expression in fibroblast-like synoviocytes from patients with tibia plateau fracture

Progression to osteoarthritis (OA) is a frequent sequela of severe articular fracture, particularly when weight-bearing joints are involved. Prevention from post-traumatic OA remains a challenge. Hyaluronan (HA) therapy is reported to represent a safe and effective treatment for patients with OA and rheumatoid arthritis. However, the capacity of HA to prevent the occurrence of osteoarthritic changes in fractured joints has not been demonstrated. The present study was undertaken to examine the effects of HA on expression of six OA-related proteins in fibroblast-like synoviocytes (FLS) from 10 patients with tibia plateau fracture. OA-related factors were quantified using a sandwich enzyme-linked immunosorbent assay. Regardless of induction of the FLS with interleukin (IL)-1β, HA was found to down-regulate expression of catabolic factors (IL-1β, matrix metalloproteinase-3, and tumor necrosis factor-α) and to up-regulate production of anti-catabolic factors (tissue inhibitors of metalloproteinase-1 and metalloproteinase-2). HA also enhanced expression of IL-10, an anti-inflammatory cytokine, in FLS. Our results indicated that HA can promote the expression of both antiinflammatory and structure-protective factors in FLS of patients with tibia plateau fracture.

Comparison of bioartificial pancreas performance in the bone marrow cavity and intramuscular space

BACKGROUND AND AIMS

Bone marrow with a widely distributed and well-vascularized microenvironment that is capable of sustaining grafts is a potential site for islet transplantation. The femur bone marrow cavity offers sufficient space that may also receive the implantation of bioartificial pancreas (BAP).

METHODS

Mouse insulinoma cells encapsulating in agarose gel were further enclosed in a calcium phosphate cement chamber to create a BAP. BAPs implanted into the femur bone marrow cavity of diabetics were compared with those implanted in the intramuscular space. Blood glucose level and C-peptide were determined perioperatively.

RESULTS

The blood glucose level of the diabetics receiving BAPs in the intramuscular space decreased from 413 +/- 24 to 285 +/- 47 mg/dL at 1 day post-surgery. However, the blood glucose level returned to 398 +/- 35 mg/dL with undetectable serum C-peptide at 2 weeks postoperatively that reveals implant failure. The blood glucose level of diabetics receiving BAPs into the femur bone marrow cavity decreased from 422 +/- 32 to 247 +/- 52 mg/dL and maintained in the range of 288 +/- 47 mg/dL during the experimental period with an increase in C-peptide level from 6.1 +/- 2.8 to 104.7 +/- 16.4 pmol/L.

CONCLUSIONS

This preliminary study indicates that the effectiveness of BAPs transplanted into the femur bone marrow cavity is superior to that implanted in the intramuscular space, which reveals the bone marrow may be a potential receptor site for the BAP transplantation.

Bone marrow combined with dental bud cells promotes tooth regeneration in miniature pig model

Growth factors and morphogens secreted by bone marrow mesenchymal stem cells (BMSCs) of bone marrow fluid may promote tooth regeneration. Accordingly, a tissue engineering approach was utilized to develop an economical strategy for obtaining the growth factors and morphogens from BMSCs. Unerupted second molar tooth buds harvested from miniature pigs were cultured in vitro to obtain dental bud cells (DBCs). Bone marrow fluid, which contains BMSCs, was collected from the porcine mandible before operation. DBCs suspended in bone marrow fluid were seeded into a gelatin/chondoitin-6-sulfate/hyaluronan tri-copolymer scaffold (GCHT scaffold). The DBCs/bone marrow fluid/GCHT scaffold was autografted into the original alveolar sockets of the pigs. Radiographic and histological examinations were applied to identify the structure of regenerated tooth at 40 weeks postimplantation. The present results showed that one pig developed a complete tooth with crown, root, pulp, enamel, dentin, odontoblast, cementum, blood vessel, and periodontal ligament in indiscriminate shape. Three animals had an unerupted tooth that expressed dentin matrix protein-1, vascular endothelial growth factor, and osteopontin; and two other pigs also had dental-like structure with dentin tubules. This study reveals that DBCs adding bone marrow fluid and a suitable scaffold can promote the tooth regeneration in autogenic cell transplantation.

Induction of the mitochondria apoptosis pathway by phytohemagglutinin erythroagglutinating in human lung cancer cells

BACKGROUND

Deregulation of apoptosis will influence the balance of cell proliferation and cell death, resulting in various fatal diseases that can include cancer. In prior research reports related to cancer therapy, phytohemagglutinin, a lectin extracted from red kidney beans, demonstrated the ability to inhibit the growth of human cancer cells. However, one of its isoforms, erythroagglutinating, has yet to be evaluated on its anticancer effects.

METHODS

PHA-E was used to induce apoptosis of A-549 lung cancer cells and the possible signal transduction pathway was elucidated, as measured by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, G6PD release assay, flow cytometry, and Western blot analysis.

RESULTS

PHA-E treatment caused a dose-dependent increase of cell growth inhibition and cytotoxicity on A-549 cells. In annexin V/propidium iodide [i.e., PI] and TUNEL (terminal deoxynucleotidyl transferase dUTP nick-end labeling)/PI assay, we found that the rate of apoptotic cells was raised as the concentration of PHA-E increased. Treatment of A-549 cells with PHA-E resulted in enhancing the release of cytochrome c, which thus activated an increase in caspase 9 and caspase 3, the upregulation of Bax and Bad, the downregulation of Bcl-2 and phosphorylated Bad, and finally the inhibition of the epidermal growth factor receptor and its downstream signal pathway PI3K/Akt and MEK/ERK.

CONCLUSIONS

PHA-E can induce growth inhibition and cytotoxicity of lung cancer cells, which is mediated through an activation of the mitochondria apoptosis pathway. These results suggest that PHA-E can be developed into a new therapeutic treatment that can be applied as an effective anti-lung cancer drug in the near future.

Lovastatin promotes redifferentiation of human nucleus pulposus cells during expansion in monolayer culture

To acquire the capacities for matrix production and preservation of an expanded volume within a damaged intervertebral disc (IVD), cells isolated from human nucleus pulposus (NP) tissues must undergo several passages in monolayer culture. However, chondrocytes and IVD cells in monolayer culture undergo "dedifferentiation," characterized by decreased synthesis of type II collagen and increased synthesis of type I collagen, thereby compromising the properties of regenerative tissues. The present study was undertaken to ascertain whether lovastatin reverses "dedifferentiation" of human NP cells during monolayer expansion. Expression of genes encoding type II collagen and transcription factor SOX9 in these cells was upregulated by lovastatin, with maximal stimulations observed at 5 µM, whereas type I collagen gene expression was suppressed by the drug, with maximal inhibitions observed at 5-10 µM. At lovastatin concentrations ≥1 µM, expression of genes encoding the bone morphogenetic proteins BMP-2 and BMP-7 was also significantly enhanced. Furthermore, the number of NP cells exhibiting a rounded shape and positive staining for S-100 protein and type II collagen protein increased during treatment with lovastatin. These findings strongly support the induction by lovastatin of "redifferentiation" of human NP cells during their expansion in monolayer culture.

Thermosensitive chitosan-gelatin-glycerol phosphate hydrogels as a cell carrier for nucleus pulposus regeneration: an in vitro study

Injectable hydrogel is one of the great interests for tissue engineering and cell encapsulation. In the study, the gelatin molecules were added to the thermosensitive chitosan/beta-glycerol phosphate (C/GP) disodium salt hydrogels to form chitosan/gelatin/beta-glycerol phosphate (C/G/GP) disodium salt hydrogels which were applied as a cell carrier for nucleus pulposus (NP) regeneration. The gelation temperature, gelation time, and gel strength of the C/G/GP hydrogels were analyzed by the rheometer. NP cells were then harvested from the intervertebral discs of the adult New Zealand white rabbits and cultured in monolayer or in C/G/GP hydrogel, respectively. The cell viability, material-mediated cytotoxicity, cell proliferation, production of sulfated glycosaminoglycans, anabolic/catabolic gene expressions, and extracellular matrix-related gene expressions of the NP cells were demonstrated. The results show that the sol/gel transition temperature of the C/G/GP hydrogel was in the range of 31.1-33.8 degrees C at neutral pH value, the gelation time was shortened, and the gel strength also improved at body temperature when compared with the C/GP hydrogel. Among those, C/GP with 1% gelatin addition showed the most promising gelation time and gel strength and were utilized in the later experiments. From the results of cell activity, cytotoxicity, and cell proliferation assays, NP cells cultured in C/G/GP hydrogel had normal cell viability and cell proliferation that indicated the hydrogel was noncytotoxicity. The amounts of sulfated glycosaminoglycans of NP cells cultured in C/G/GP hydrogels were significantly higher than monolayer cultured. Considering the extracellular matrix-related gene expression, type II collagen and aggrecan of NP cells cultured in the hydrogels greatly increased than those in monolayer culture. On the contrary, the unfavorable gene expression, such as that of type I collagen, was decreased significantly. The results reveal that gelatin added into C/GP hydrogel significantly shortened the gelation time and improved the gel strength without influencing the biocompatibility. NP cells cultured in the C/G/GP hydrogel also displayed better gene expressions when compared with the monolayer culture. This study indicates that using chitosan/gelatin hydrogel for NP cell culture is feasible and may apply in minimal invasive intervertebral disc surgery in the future.

Injectable oxidized hyaluronic acid/adipic acid dihydrazide hydrogel for nucleus pulposus regeneration

Injectable hydrogel allows irregular surgical defects to be completely filled, lessens the risk of implant migration, and minimizes surgical defects due to the solution-gel state transformation. Here, we first propose a method for preparing oxidized hyaluronic acid/adipic acid dihydrazide (oxi-HA/ADH) injectable hydrogel by chemical cross-linking under physiological conditions. Fourier transform infrared spectrometry and trinitrobenzene sulfonate assay were used to confirm the oxidation of hyaluronic acid. Rheological properties were measured to evaluate the working ability of the hydrogel for further clinical application. The oxi-HA/ADH in situ forming hydrogel can transform from liquid form into a gel-like matrix within 3-8 min, depending on the operational temperature. Furthermore, hydrogel degradation and cell assessment is also a concern for clinical application. Injectable oxi-HA/ADH8 hydrogel can maintain its gel-like state for at least 5 weeks with a degradation percentage of 40%. Importantly, oxi-HA/ADH8 hydrogel can assist in nucleus pulposus cell synthesis of type II collagen and aggrecan mRNA gene expression according to the results of real-time PCR analysis, and shows good biocompatibility based on cell viability and cytotoxicity assays. Based on the results of the current study, oxi-HA/ADH hydrogel may possess several advantages for future application in nucleus pulposus regeneration.

Simvastatin promotes osteoblast viability and differentiation via Ras/Smad/Erk/BMP-2 signaling pathway

Statins inhibit 3-hydroxy-3-methylglutaryl-coenzyme A reductase, which catalyzes the conversion of 3-hydroxy-3-methylglutaryl-coenzyme A to mevalonate, a rate-limiting step in cholesterol synthesis. Statins are able to reduce cardiovascular risk in hypercholesterolemic patients. In recent years, the possible effect of statins on bone tissue has received particular attention. The present study was undertaken to understand the events of osteoblast differentiation induced by statins. Our hypothesis is that simvastatin promotes osteoblast viability and differentiation via Ras/Smad/Erk/bone morphogenic protein (BMP)-2 signaling pathway. The viability and differentiation of osteoblasts were examined by mitochondrial activity assay, alkaline phosphatase (ALP) activity, and gene expression. The associated signaling pathways were analyzed by cytoplasmic and membrane proteins manifestation. After administration of 10(-6) M simvastatin, the ALP activity was significantly enhanced, and the expression of BMP-2, ALP, sialoprotein, and type I collagen genes were up-regulated. After simvastatin treatment, both the RasGRF1 and phospho-RasGRF1 in the cytoplasm decreased significantly, whereas those on the plasma membrane increased. A marked increase in membranous GAP-associated protein (P190) and the activated form of both phospho-extracellular signal-regulated kinase1/2 and phospho-Smad1 were also noted. In conclusion, this study shows that statins pose a positive effect on the metabolism of osteoblasts. Simvastatin can promote osteoblast viability and differentiation via membrane-bound Ras/Smad/Erk/BMP-2 pathway. Statins stimulate osteoblast differentiation in vitro and may be a promising drug for the treatment of osteoporosis in the future.

Gadolinium hexanedione nanoparticles for stem cell labeling and tracking via magnetic resonance imaging

The ability to trace transplanted stem cells and monitor their tissue biodistribution is prerequisite to an understanding of cellular migration after transplantation. Therefore, a new magnetic resonance imaging (MRI) contrast agent made of gadolinium hexanedione nanoparticles (GdH-NPs) was developed as a cell tracking agent. The GdH-NPs were fabricated by the microemulsion process. The physical characteristics, biocompatibility, and T1-MRI signal enhancement of these NPs were analyzed and evaluated for stem cell tracking. In this study, the size of the synthesized GdH-NPs was about 140 nm, and it had greater image enhancement ability than commercial gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA). From the biocompability test, we found GdH-NPs were nontoxic for human mesenchymal stem cells (hMSCs). The expression of surface antigens of hMSCs after culture with GdH-NPs was examined, and it showed no difference from the control group. The results of transmission electron microscopy (TEM) imaging for labeled hMSCs showed GdH-NPs were accumulated in the cells by the endocytotic pathway. The accumulation of GdH-NPs in hMSCs was three times higher in comparison to Gd-DTPA. Human MSCs labeled with low concentration of GdH-NPs (10 microg/mL) hold better signals in cellular MR image. We conclude GdH-NPs can be used to label hMSCs in vitro with greater T1 image-enhancing property and without affecting cell quality. Finally, GdH-NPs have great potential as a contrast agent for stem cell tracking by MRI methodology.

The chondroprotective effects of ferulic acid on hydrogen peroxide-stimulated chondrocytes: inhibition of hydrogen peroxide-induced pro-inflammatory cytokines and metalloproteinase gene expression at the mRNA level

OBJECTIVE

The objective of the study is to evaluate the effect of ferulic acid (FA), an antioxidant from the Chinese herb Dong-Gui [Chinese angelica, Angelica sinensis (Oliv.) Diels], on the regulation of various genes in hydrogen peroxide-stimulated porcine chondrocytes at the mRNA level.

METHODS

The effect of FA and the effective concentration of FA on porcine chondrocytes was evaluated by the lactate dehydrogenase, WST-1, crystal violet assay, and a chemical luminescence assay. Gene expression in hydrogen peroxide-stimulated chondrocytes either pre- or post-treated with FA was evaluated by real-time PCR.

RESULTS

Chondrocytes pre-treated with 40 microM FA decreased the hydrogen peroxide-induced interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), and MMP-1 and partially restored SOX9 gene expression. Post-treatment with 40 microM FA also decreased the expression of MMP-1 and MMP-13.

CONCLUSION

FA decreased the hydrogen peroxide-induced IL-1beta, TNF-alpha, MMP-1 and MMP-13 and increased SOX9 gene expression. These findings suggest that FA may prove to be important in the treatment of osteoarthritis. Further research is needed.

Large-scale bicortical skull bone regeneration using ex vivo replication-defective adenoviral-mediated bone morphogenetic protein-2 gene-transferred bone marrow stromal cells and composite biomaterials

OBJECTIVE

Bone marrow stromal cells (BMSCs) have great potential in bone repair. We developed an animal model to test the hypothesis that ex vivo gene transfer of human bone morphogenetic protein (BMP)-2 to BMSCs via a replication-defective (E1A-deleted) adenovirus vector (AdV) with appropriate biopolymers would enhance autologous bone formation during repair of a large-scale skull defect.

METHODS

Eighteen miniature swine were treated with AdV BMP-2-transduced BMSCs in biopolymer (group 1), BMSCs in biopolymer (group 2), or biopolymer alone (group 3). After 6 months, the swine were killed, and the skull repair was examined by gross pictures, histology, 3-dimensional computed tomography, and biomechanical study.

RESULTS

Group 1 showed complete solid bone formation after 6 months, and hematoxylin and eosin staining demonstrated the presence of mature, woven, well-mineralized bone. Computed tomography showed wholesome repair of the skull defect. Statistical analysis demonstrated a significant difference in bone thickness between groups 1 and 2. Biomechanical testing showed a statistically significant difference in the stiffness of new bone formed in group 1 compared with group 2.

CONCLUSION

The Ad5 E1A-deleted AdV may be the optimal starting vector in ex vivo gene therapy for benign skeletal diseases. Additionally, the use of the gelatin/tricalcium phosphate ceramic/glutaraldehyde biopolymer with AdV BMP-2 gene transfer strongly enhances the bony healing of critical-size bicortical craniofacial defects. This method can be used by modifying the delivery of constructs to malunion treatment, in regional osteoporosis therapy, and spinal fusion.

Influence of age-related degeneration on regenerative potential of human nucleus pulposus cells

Nucleus pulposus (NP) cells, sourced from herniation surgeries, may be used as a cell-based therapy for intervertebral disc (IVD) degeneration. But, both the regenerative potential of these degenerative adult NP cells and how to stimulate optimum matrix synthesis is not yet clear. The purpose of the current study was to understand the different phenotypic behaviors between degenerative adult NP cells and normal adolescent NP cells. Degenerative adult NP cells produced a significantly higher amount of proteoglycans and collagens than adolescent cells. Insulin-like growth factor-1 was the only anabolic cytokine with increased endogenous expression in degenerative adult NP cells. TGF-beta1 treatment of degenerative NP cells promoted matrix synthesis but stimulated too much type I collagen and suppressed type II collagen and aggrecan. Adult degenerative NP cells possess upregulated regenerative potential, but stimulation in addition to TGF-beta1 is needed to enhance matrix productivity and optimize the collagen expression profile.

A new fish scale-derived scaffold for corneal regeneration

The purpose of this study is to develop a novel scaffold, derived from fish scales, as an alternative functional material with sufficient mechanical strength for corneal regenerative applications. Fish scales, which are usually considered as marine wastes, were acellularized, decalcified and fabricated into collagen scaffolds. The microstructure of the acellularized scaffold was imaged by scanning electron microscopy (SEM). The acellularization and decalcification treatments did not affect the naturally 3-dimentional, highly centrally-oriented micropatterned structure of the material. To assess the cytocompatibility of the scaffold with corneal cells, rabbit corneal cells were cultured on the scaffold and examined under SEM and confocal microscopy at different time periods. Rapid cell proliferation and migration on the scaffold were observed under SEM and confocal microscopy. The highly centrally-oriented micropatterned structure of the scaffold was beneficial for efficient nutrient and oxygen supply to the cells cultured in the three-dimensional matrices, and therefore it is useful for high-density cell seeding and spreading. Collectively, we demonstrate the superior cellular conductivity of the newly developed material. We provide evidences for the feasibility of the scaffold as a template for corneal cells growth and migration, and thus the fish scale-derived scaffold can be developed as a promising material for tissue-engineering of cornea.

The cytoprotection of chitosan based hydrogels in xenogeneic islet transplantation: An in vivo study in streptozotocin-induced diabetic mouse

Immune rejection and scarcity of donor tissues are the restrictions of islets transplantation. In this study, the cytoprotection of chitosan hydrogels in xenogeneic islet transplantation was demonstrated. Wistar rat islets encapsulated in chitosan hydrogels were performed glucose challenge test and live/dead cell staining in vitro. Islets/chitosan hydrogels were transplanted into the renal subcapsular space of diabetic C57BL/6 mice. Non-fasting blood glucose level (NFBG), body weight, intraperitoneal glucose tolerance test (IPGTT), and glucose disappearance rate were determined perioperatively. The serum insulin level was analyzed, and the kidney transplanted with islets/chitosan hydrogels were retrieved for histological examination after sacrifice. The present results showed that islets encapsulated in chitosan hydrogels secreted insulin in response to the glucose stimulation as naked islets with higher cell survival. The NFBG of diabetic mice transplanted with islets/chitosan hydrogels decreased from 487+/-46 to 148+/-32 at one day postoperation and maintained in the range of 201+/-36 mg/dl for four weeks with an increase in body weight. IPGTT showed the glucose disappearance rate of mice transplanted with islets/chitosan hydrogels was significant faster than that of mice transplanted with naked islets; the serum insulin level increased from 0.29+/-0.06 to 1.69+/-0.65 microg/dl postoperatively. Histological examination revealed that the islets successfully engrafted at renal subcapsular space with positive insulin staining. The immunostain was negative for neither the T-cell lineages nor the monocyte/macrophages. This study indicates that the chitosan hydrogels deliver and protect encapsulated islets successfully in xenotransplantation.

MicroSPECT/CT imaging and pharmacokinetics of 188Re-(DXR)-liposome in human colorectal adenocarcinoma-bearing mice

Nanoliposome can be designed as a drug delivery carrier to improve the pharmacological and therapeutic properties of drug administration. (188)Re-labeled nanoliposomes are useful for diagnostic imaging as well as for targeted radionuclide therapy. In this study, the in vivo nuclear imaging, pharmacokinetics and biodistribution of administered nanoliposomes were investigated as drug and radionuclide carriers for targeting solid tumor via intravenous (i.v.) administration. The radiotherapeutics ((188)Re-liposome) and radiochemotherapeutics ((188)Re-DXR-liposome) were i.v. administered to nude mice bearing human HT-29 colorectal adenocarcinoma xenografts. (188)Re-liposome and (188)Re-DXR-liposomes show similar biodistribution profile; both have higher tumor uptake, higher blood retention time, and lower excretion rate than (188)Re-N,N-bis(2-mercaptoethyl)-N',N'-diethylenediamine (BMEDA). In contrast to tumor uptake, the area under the curve (AUC) value of tumor for (188)Re-liposome and (188)Re-DXR-liposome was 16.5- and 11.5-fold higher than that of free (188)Re-BMEDA, respectively. Additionally, (188)Re-liposome and (188)Re-DXR-liposome had a higher tumor-to-muscle ratio at 24 h (14.4+/-2 .7 and 17.14+/-4.1, respectively) than (188)Re-BMEDA (1.6+/-0.1). The tumor targeting and distribution of (188)Re-(DXR)-liposome (representing (188)Re-DXR-liposome and (188)Re-liposome) can also be acquired by signal photon-emission computed tomography/computed tomography images as well as whole body autoradiograph. These results suggest that (188)Re-(DXR)-liposomes are potentially promising agents for passive targeting treatment of malignant disease.

Dual chemotherapy and photodynamic therapy in an HT-29 human colon cancer xenograft model using SN-38-loaded chlorin-core star block copolymer micelles

Chlorin-core star-shaped block copolymer (CSBC) may self-assemble to form micelles, which act as nanosized photosensitizing agents for photodynamic therapy (PDT) and further encapsulate hydrophobic drugs. This functionalized micellar delivery system is a potential dual carrier for the synergistic combination of photodynamic therapy and chemotherapy for the treatment of cancer. In this study, SN-38 encapsulated CSBC micelles were successfully prepared using a lyophilization-hydration method. Our results show that the prolonged plasma residence time of SN-38/CSBC micelles as compared with free CPT-11 permit increased tumor accumulation and consequently, improved antitumor activity. The combined effects of SN-38/CSBC micelles with PDT were evaluated in an HT-29 human colon cancer xenograft model. Interesting, SN-38/CSBC-mediated PDT synergistically inhibited tumor growth, resulting in up to 60% complete regression of well-established tumors after 3 treatments. These treatments also decreased the microvessel density (MVD) and cell proliferation within the subcutaneous tumors. Therefore, this SN-38/CBSC delivery system has the potential to offer dual therapies for the synergistic combination of PDT and chemotherapy for the treatment of cancer.

Regulation of adult human mesenchymal stem cells into osteogenic and chondrogenic lineages by different bioreactor systems

The aim of this study was to examine the feasibility of expanding and regulating mesenchymal stem cells (MSCs) from isolated adult human bone marrow mononuclear cells, seeded on gelatin-hyaluronic acid biomatrices, and then to quantitatively compare the gene expression in three different culture systems. Individual and interactive effects of model system parameters on construct structure, function, and molecular properties were evaluated. The results showed that these adult human MSCs even at old age not only expressed primitive mesenchymal cell markers but also maintained a high level of colony-forming efficiency and were capable of differentiating into osteoblasts, chondrocytes, and adipocytes upon appropriate inductions. After 21 days of culture, we found that the osteoblastic and chondrocytic lineage gene expression were earlier and higher expressed in spinner flask bioreactor culture group when compared with the static culture and rotating wall vessel reactor culture. The osteogenic lineage proteins type I collagen, alkaline phosphatase, and osteocalcin were strongly stained in histological sections of spinner flask bioreactor culture, whereas these were less detected in the other two groups, especially in rotating wall vessel reactor culture. As for the markers associated with the chondrogenic lineage differentiation proteins, type II collagen was apparently expressed in spinner flask culture group, while the expression of proteoglycans (aggreacan, decorin) in three culture conditions took the lead of each other. We conclude that the spinner flask bioreactor with appropriate induction medium reported in this study may be used to rapidly expand adult MSCs and is likely to possess better induction results toward osteoblastic and chondrocytic lineages.

Surgical treatment for non-union of the mid-shaft clavicle using a reconstruction plate: scapular malposition is related to poor results

A retrospective study was performed to evaluate the use of an AO reconstruction plate in open reduction and internal fixation for non-union of the mid-shaft clavicle, examining the relationship between the position of the scapula and final functional results and whether perioperative variables such as clavicular reconstruction ratio and period of non-union influence the position of the scapula. From January 1998 to January 2005, data on 21 people with symptomatic non-union of the mid-shaft clavicle were collected; 17 non-unions were atrophic and 4 were hypertrophic. Initially, treatment was conservative with a figure-of-eight bandage in 19 cases, and cerclage wire fixation in 2 cases. The follow-up period was 65.7 (24-108) months. Outcome analyses included standard clinical follow-up, plain radiography, the Constant-Murley scoring and subjective assessment. All non-unions united well in 13.6 (11-27) weeks. All patients were satisfied with their surgical results. Greater age and longer period of non-union resulted in a larger amount of scapular malposition, which related to poor functional results.

Regeneration of dentin-pulp complex with cementum and periodontal ligament formation using dental bud cells in gelatin-chondroitin-hyaluronan tri-copolymer scaffold in swine

The purpose of this study is to use a tissue engineering approach for tooth regeneration. The swine dental bud cells (DBCs) were isolated from the developing mandibular teeth, expanded in vitro, and cultured onto cylinder scaffold gelatin-chrondroitin-hyaluronan-tri-copolymer (GCHT). After culturing in vitro, the DBCs/GCHT scaffold was autografted back into the original alveolar socket. Hematoxylin and eosin (H&E) staining combined with immunohistochemical staining were applied for identification of regenerated tooth structure. After 36-week post-transplantation, tooth-like structures, including well-organized dentin-pulp complex, cementum, and periodontal ligament, were evident in situ in two of six experimental animals. The size of the tooth structure (1 x 0.5 x 0.5 cm(3) and 0.5 x 0.5 x 0.5 cm(3) size) appeared to be dictated by the size of the GCHT scaffold (1 x 1 x 1.5 cm(3)). The third swine was demonstrated with irregular dentin-bony like calcified tissue about 1 cm in diameter without organized tooth or periodontal ligament formation. The other three swine in the experimental group showed normal bone formation and no tooth regeneration in the transplantation sites. The successful rate of tooth regeneration from DBCs/GCHT scaffolds' was about 33.3%. In the control group, three swine's molar teeth buds were removed without DBCs/GCHT implantation, the other three swine received GCHT scaffold implants without DBCs. After evaluation, no regenerated tooth was found in the transplantation site of the control group. The current results using DBSs/GCHT scaffold autotransplantation suggest a technical breakthrough for tooth regeneration.

Three-dimensional culture of human nucleus pulposus cells in fibrin clot: comparisons on cellular proliferation and matrix synthesis with cells in alginate

Regeneration of nucleus pulposus (NP) tissue may stop or reverse early intervertebral disk (IVD) degeneration. Cellular proliferation and matrix synthesis can be promoted by incorporation of cells and bioscaffolds. However, insertion of preshaped solid bioscaffolds may damage remaining IVD integrity. Fibrin clots can be introduced in a minimally invasive manner with polymerization in desired three-dimensional shape and retention of cells. In this study, we investigated the cellular proliferation and matrix synthesis of human NP cells in the fibrin clots in vitro. Monolayer-expanded cells were embedded in fibrin clot or alginate and were cultivated in vitro for 2 weeks. Increased DNA content and decreased expression of apoptosis stimulating fragment (Fas)-associated death-domain protein in fibrin scaffolds suggested higher cellular proliferation and reduced apoptosis. Superior proteoglycan synthesis was found in fibrin scaffolds. As expression of collagens I and X increased and SOX9 expression decreased, fibrin scaffolds tended to promote fibrotic transformation and inhibit chondrogenesis. Adjustments of fibrin preparations are needed to make it more suitable for IVD regeneration.

Synthesis of partial-stabilized cement (PSC) via sol–gel process

The traditional method of preparing partial-stabilized cement (PSC), which is a kind of calcium silicate cement, is through power mixing method. Low reaction efficiency and initial strength limited the application of PSC as a dental root-end filling material. This study provides a one-step sol-gel process for the synthesis of PSC. A complexing ligand is used for tuning down the activity of aluminum sec-butoxide (ASB) in order to avoid possible self-polymerization. After the modification with complex ligand, there is no residue of reactant observed on the analysis of SDT, and bonding between metal atoms is observed in the FTIR spectrum. Each component of PSC is identified using XRD. The hydration product, which is called portlandite, of sol-gel-synthesized PSC is observed after 1 day of hydration, and crystallinity of portlandite increases much faster than that of traditional PSC. The initial strength of sol-gel-synthesized PSC achieves detectable level 24 h earlier than that of traditional PSC; microhardness value of sol-gel-synthesized PSC at 7th day is 2.98 HV, which is much higher than that of traditional PSC (2.05 HV). PSC is successfully synthesized and the initial strength of PSC is improved by this modified sol-gel process.

In vitro study of root fracture treated by CO2 laser and DP-bioactive glass paste

BACKGROUND/PURPOSE

An ideal material has yet to be discovered that can successfully treat vertical root fracture. Therefore, the purpose of this study was to use a continuous-wave CO2 laser of medium-energy density to fuse DP-bioactive glass paste (DPGP) to vertical root fracture.

METHODS

The DP-bioglass powder was based on a Na2O-CaO-SiO2-P2O5 system and it was mixed with phosphoric acid (65% concentration) with a powder/liquid ratio of 2 g/4 mL to form DPGP. The interaction of DPGP and dentin was analyzed by means of X-ray diffractometer (XRD) and differential thermal analysis/thermogravimetric analysis (DTA/TGA). Root fracture line was filled with DPGP followed by CO2 laser irradiation and the result was examined by scanning electron microscopy (SEM).

RESULTS

The main crystal phase of DPGP was monocalcium phosphate monohydrate (Ca(H2PO4)2.H2O) and the phase transformed to dicalcium phosphate dihydrate (CaHPO4.2H2O) after mixing DPGP with dentin powder (DPG-D). Additionally, gamma-Ca2P2O7 and beta-Ca2P2O7 were identified when DPG-D was lased by CO2 laser. The reaction temperature was between 500 degrees C and 1100 degrees C. SEM results demonstrated that the fracture line was effectively sealed by DPGP.

CONCLUSION

The chemical reaction of DPGP and dentin indicated that DPGP combined with CO2 laser is a potential regimen for the treatment of vertical root fracture.

Chitosan/poly(vinyl alcohol) blending hydrogel coating improves the surface characteristics of segmented polyurethane urethral catheters

Segmented polyurethane (SPU) is commonly used to manufacture urethral catheters. Surface modifications for SPU catheters are needed to reduce friction and protein adsorption, in order to minimize catheter-related complications, including urethral trauma, encrustation, catheter obstruction, bacterial colonization, and infection. In this study, a four-step surface modification method was developed to create a thin lubricious layer of chitosan/poly(vinyl alcohol) (PVA) hydrogel on the SPU catheter. Modification steps included oxidation of the SPU surface, functionalities modification, carbodiimide reaction and coupling, and hydrogel crosslinking. The success of each modification step was confirmed by Fourier transform infrared spectroscopy. Measurement of the water contact angle revealed that hydrogel coating created a highly hydrophilic surface and atomic force microscope analyses demonstrated that the surface was slippery. Protein absorption of the SPU catheter was significantly reduced by coating hydrogel. Chitosan in the hydrogel could provide antimicrobial activity, and the hydrogel coating SPU samples showed significant antibacterial effects in this study. In summary, the four-step modification method developed in this study provided a simple and effective way to coat the surface of SPU catheters with a chitosan/PVA blending hydrogel that could help to minimize the risk of complications related to the use of urethral catheters.

The development of magnetic degradable DP-Bioglass for hyperthermia cancer therapy

In this study, a novel magnetic degradable material was developed by adding Fe ions into DP-Bioglass (Na(2)O-CaO-P(2)O(5)-SiO(2)) as thermoseed for hyperthermia cancer therapy under an alternating magnetic field. We have investigated the properties of developed magnetic DP-Bioglass including morphology, chemical composition, and magnetism. The degradability was conducted by measuring the released concentrations of Na, Ca, Si, P, and Fe ions. The biocompatibility was analyzed by biological assays, and the functional hyperthermia effect to cancer cells was evaluated by in vitro cell culture test. In the results, the morphology of synthesized magnetic DP-Bioglass was revealed in sphere and rod shape with particle size around 50-100 nm. From the hysteresis loop analysis, it showed that the group of Fe/Bioglass = 0.2 possessed the maximum magnetization property. When cultured with fibroblasts, the magnetic DP-Bioglass had no significant influence on cell viability and mediated low cytotoxicity. The thermal-induced property demonstrated that after exposure to an alternating magnetic field, the cell number of human Caucasian lung carcinoma cells (A549) was significantly decreased when temperature was increasing to 45 degrees C. In brief, successfully incorporated with Fe ions by sol-gel method, this magnetic degradable DP-Bioglass possessed the potential and properties of hyperthermia effect to lung carcinoma cells.

Development of gelatin nanoparticles with biotinylated EGF conjugation for lung cancer targeting

Since lung cancer is the most malignant cancer today, a specific drug-delivery system has been developed for superior outcome. In this study, gelatin nanoparticles (GPs) employed as native carriers were grafted with NeutrAvidin(FITC) on the particle's surface (GP-Av). Next, the biotinylated epithelial growth factor (EGF) molecules were conjugated with NeutrAvidin(FITC), forming a core-shell-like structure (GP-Av-bEGF) to achieve the enhancement of targeting efficiency. These nanoparticles were applied as an EGF receptor (EGFR)-seeking agent to detect lung adenocarcinoma. The results showed that the modification process had no significant influence on particle size (220 nm) and zeta potential (-9.3 mV). By the in vitro cell culture test, GP-Av-bEGF resulted in higher entrance efficiency on adenocarcinoma cells (A549) than that on normal lung cells (HFL1) because A549 possessed greater amounts of EGFR. We also found that uptake of GP-Av-bEGF by A549 cells was time and dose dependent. Confocal microscopy confirmed the cellular internalization of GP-Av-bEGF, and more fluorescent spots of GP-Av-bEGF nanoparticles were obviously observed as well as lysosomal entrapment in A549. Finally, the delivery was demonstrated by in vivo aerosol administration to cancerous lung of the SCID mice model, and specific accumulation in cancerous lung was confirmed by image quantification. The targeting ability of GP-Av-bEGF was proved in vitro and in vivo, which holds promise for further anti-cancer drug applications.

Cytotoxicity of DP-Bioglass Paste Used for Treatment of Dentin Hypersensitivity

DP-bioglass mixed with 30% phosphoric acid has been suggested to treat dentin hypersensitivity because the material is able to produce homogeneous occlusion of exposed dentinal tubules and is able to provide a sealing depth of up to 60 microm. The purpose of this study was to investigate the relative cytotoxic effect of the DP-bioglass paste, intermediate restorative material (IRM; DeTrey, Dentsply, Germany), and commercial desensitizing agent (Abmindent; Abmin Technologies Ltd, Turku, Finland) on human dental pulp cells by using a transwell insert model and a dentin-disc model. Cell viability was measured by means of a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The results of this study indicated that cell viability for the DP-bioglass paste did not differ significantly from those of the IRM or Abmindent in the transwell insert model. In addition, MTT results of DP-bioglass paste were similar to the control group in the dentin-disc model. The results indicated that DP-bioglass paste was a highly biocompatible material and could potentially serve as an effective material for treatment of dentin hypersensitivity.

Cytotoxicity of partial-stabilized cement

Partial-stabilized cement (PSC) is a kind of modified calcium silicate cement used for root-end surgery. Minor transition metal elements Co, Cr, and Zn were added for enhancing the setting property of to PSC. In our previous study, minor transition metal additions greatly improved the setting property of PSC. However, the concern of metal toxicity was raised, as the material would be used in the human body. In this study, we evaluated the cytotoxicity of PSC in comparison with mineral trioxide aggregate (MTA), which is one of the commercialized materials used for dental root-end filling. Primary osteoblast cell was used as the target cell. Cell proliferation, cytotoxicity, viability, function, and senescence were analyzed. The cytotoxicity of the PSC-Zn group (PSC with Zn addition) was similar to that of MTA. PSC-Zn is not only nontoxic at the cellular level but also has adequate mechanical property, which makes it a potential root-end filling material for apical surgery.

Evaluation and biological characterization of bilayer gelatin/chondroitin-6-sulphate/hyaluronic acid membrane

A biodegradable polymer scaffold was developed using gelatin, chondroitin-6-sulphate, and hyaluronic acid in the form of bilayer network. The bilayer porous structure of gelatin-chondroitin-6-sulphate-hyaluronic acid (G-C6S-HA) membrane was fabricated using different freezing temperatures followed by lyophilization. 1-Ethyl-3(3-dimethylaminopropyl) carbodiimide was used as crosslinking agent to improve the biological stability of the scaffold. The morphology, physical-chemical properties, and biocompatibility of bilayer G-C6S-HA membrane were evaluated in this study. The functional groups change in crosslinked G-C6S-HA scaffold was characterized by fourier transform infrared spectroscopy. The retention of glycosaminoglycan contents and matrix degradation rate were also examined by p-dimethylamino benzaldehyde and 2,4,6-trinitrobenzene sulphonic acid, respectively. Water absorption capacity was carried out to study G-C6S-HA membrane water containing characteristics. The morphology of the bilayer G-C6S-HA membrane was investigated under scanning electron microscope and light microscopy. In vitro biocompatibility was conducted with MTT test, LDH assay, as well as histological analysis. The results showed that the morphology of bilayer G-C6S-HA membrane was well reserved. The physical-chemical properties were also adequate. With good biocompatibility, this bilayer G-C6S-HA membrane would be suitable as a matrix in the application of tissue engineering.

In Vitro Study of Dentinal Tubule Occlusion with Sol-gel DP-bioglass for Treatment of Dentin Hypersensitivity

DP-bioglass paste has been demonstrated to produce 60 microm of sealing depth on exposed dentinal tubules. However, the occlusive effect depended on a continuous placement of DP-bioglass paste on dentinal surface for three days. In a bid to fabricate highly reactive DP-bioglass particles, a sol-gel method was used together with HNO3, NaOH, and H3PO4 as catalysts. As a result, the application time of DP-bioglass paste was significantly reduced to 10 minutes. Percentage of tubular occlusion with DP-bioglass was 53.2-65.4%, while One Coat Bond and Seal & Protect yielded 51.3% and 41.2% respectively. Further, the average depth of tubular occlusion with DP-bioglass was 55.8-62.7 microm, while One Coat Bond and Seal & Protect produced 40.8 microm and 32.5 microm respectively. In conclusion, the best sealing performance of tubular occlusion was rendered by DP-bioglass catalyzed with HNO3. Its performance was significantly better than Seal & Protect, and was considered to exhibit the greatest potential in treating dentin hypersensitivity.