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.