Adipose-derived stem cells loaded photocurable and bioprintable bioinks composed of GelMA, HAMA and PEGDA crosslinker to differentiate into smooth muscle phenotype

Developing a polymer-based photocrosslinked 3D printable scaffolds comprised of gelatin methacryloyl (G) and hyaluronic acid methacryloyl (H) incorporated with two molecular weights of polyethylene glycol diacrylate (P) of various concentrations that enables rabbit adipose-derived stem cells (rADSCs) to survive, grow, and differentiate into smooth muscle cells (SMCs). Then, the chemical modification and physicochemical properties of the PGH bioinks were evaluated. The cell viability was assessed via MTT, CCK-8 assay and visualized employing Live/Dead assay. In addition, the morphology and nucleus count of differentiated SMCs were investigated by adopting TRAP (tartrate-resistant acid phosphatase) staining, and quantitative RT-PCR analysis was applied to detect gene expression using two different SMC-specific gene markers α-SMA and SM-MHC. The SMC-specific protein markers namely α-SMA and SM-MHC were applied to investigate SMC differentiation ability by implementing Immunocytofluorescence staining (ICC) and western blotting. Moreover, the disk, square, and tubular cellular models of PGH7 (GelMA/HAMA=2/1) + PEGDA-8000 Da, 3% w/v) hybrid bioink were printed using an extrusion bioprinting and cell viability of rADSCs was also analysed within 3D printed square construct practising Live/Dead assay. The results elicited the overall viability of SMCs, conserving its phenotype in biocompatible PGH7 hybrid bioink revealing its great potential to regenerate SMCs associated organs repair.

Bilayer osteochondral graft in rabbit xenogeneic transplantation model comprising sintered 3D-printed bioceramic and human adipose-derived stem cells laden biohydrogel

Reconstruction of severe osteochondral defects in articular cartilage and subchondral trabecular bone remains a challenging problem. The well-integrated bilayer osteochondral graft design expects to be guided the chondrogenic and osteogenic differentiation for stem cells and provides a promising solution for osteochondral tissue repair in this study. The subchondral bone scaffold approach is based on the developed finer and denser 3D β-tricalcium phosphate (β-TCP) bioceramic scaffold process, which is made using a digital light processing (DLP) technology and the novel photocurable negative thermo-responsive (NTR) bioceramic slurry. Then, the concave-top disc sintered 3D-printed bioceramic incorporates the human adipose-derived stem cells (hADSCs) laden photo-cured hybrid biohydrogel (HG + 0.5AFnSi) comprised of hyaluronic acid methacryloyl (HAMA), gelatin methacryloyl (GelMA), and 0.5% (w/v) acrylate-functionalized nano-silica (AFnSi) crosslinker. The 3D β-TCP bioceramic compartment is used to provide essential mechanical support for cartilage regeneration in the long term and slow biodegradation. However, the apparent density and compressive strength of the 3D β-TCP bioceramics can be obtained for ~ 94.8% theoretical density and 11.38 ± 1.72 MPa, respectively. In addition, the in vivo results demonstrated that the hADSC + HG + 0.5AFnSi/3D β-TCP of the bilayer osteochondral graft showed a much better osteochondral defect repair outcome in a rabbit model. The other word, the subchondral bone scaffold of 3D β-TCP bioceramic could accelerate the bone formation and integration with the adjacent host cancellous tissue at 12 weeks after surgery. And then, a thicker cartilage layer with a smooth surface and uniformly aligned chondrocytes were observed by providing enough steady mechanical support of the 3D β-TCP bioceramic scaffold.

A Multifunctional Polyethylene Glycol/Triethoxysilane-Modified Polyurethane Foam Dressing with High Absorbency and Antiadhesion Properties Promotes Diabetic Wound Healing

The delayed healing of chronic wounds, such as diabetic foot ulcers (DFUs), is a clinical problem. Few dressings can promote wound healing by satisfying the demands of chronic wound exudate management and tissue granulation. Therefore, the aim of this study was to prepare a high-absorption polyurethane (PU) foam dressing modified by polyethylene glycol (PEG) and triethoxysilane (APTES) to promote wound healing. PEG-modified (PUE) and PEG/APTES-modified (PUESi) dressings were prepared by self-foaming reactions. Gauze and PolyMem were used as controls. Next, Fourier transform-infrared spectroscopy, thermomechanical analyses, scanning electron microscopy and tensile strength, water absorption, anti-protein absorption, surface dryness and biocompatibility tests were performed for in vitro characterization. Wound healing effects were further investigated in nondiabetic (non-DM) and diabetes mellitus (DM) rat models. The PUE and PUESi groups exhibited better physicochemical properties than the gauze and PolyMem groups. Moreover, PUESi dressing showed better anti-adhesion properties and absorption capacity with deformation. Furthermore, the PUESi dressing shortened the inflammatory phase and enhanced collagen deposition in both the non-DM and DM animal models. To conclude, the PUESi dressing not only was fabricated with a simple and effective strategy but also enhanced wound healing via micronegative-pressure generation by its high absorption compacity with deformation.

Bone-Targeting Nanoparticles of a Dendritic (Aspartic acid)3-Functionalized PEG-PLGA Biopolymer Encapsulating Simvastatin for the Treatment of Osteoporosis in Rat Models

Simvastatin (SIM) is a lipid-lowering drug that also promotes bone formation, but its high liver specificity may cause muscle damage, and the low solubility of lipophilic drugs limits the systemic administration of SIM, especially in osteoporosis (OP) studies. In this study, we utilized the bone-targeting moiety of dendritic oligopeptides consisting of three aspartic acid moieties (_dAsp₃) and amphiphilic polymers (poly(ethylene glycol)-block-poly(lactic-co-glycolic acid); PEG-PLGA) to create _dAsp₃-PEG-PLGA (APP) nanoparticles (NPs), which can carry SIM to treat OP. An in vivo imaging system showed that gold nanocluster (GNC)-PLGA/APP NPs had a significantly higher accumulation rate in representative bone tissues. In vivo experiments comparing low-dose SIM treatment (0.25 mg/kg per time, 2 times per week) showed that bone-targeting SIM/APP NPs could increase the bone formation effect compared with non-bone-targeting SIM/PP NPs in a local bone loss of hindlimb suspension (disuse) model, but did not demonstrate good bone formation in a postmenopausal (ovariectomized) model of systemic bone loss. The APP NPs could effectively target high mineral levels in bone tissue and were expected to reduce side effects in other organs affected by SIM. However, in vivo OP model testing showed that the same lower dose could not be used to treat different types of OP.

Preparation of CO2 -based Cationic Polycarbonate/Polyacrylonitrile Nanofibers with an Optimal Fibrous Microstructure for Antibacterial Applications

Utilizing CO₂ as one of the monomer resource, poly(vinylcyclohexene carbonates) (PVCHCs) are used as the precursor for preparing cationic PVCHCs (CPVCHCs) via thiol-ene click functionalization. Through the functionalization, CPVCHC-43 with a tertiary amine density of 43% relative to the backbone is able to display a significantly antibacterial ability against Staphylococcus aureus (S. aureus). Blending CPVCHC-43 with polyacrylonitrile (PAN), CPVCHC/PAN nanofiber meshes (NFMs) have been successfully prepared by electrospinning. More importantly, two crucial fibrous structural factors including CPVCHC/PAN weight ratio and fiber diameter have been systematically investigated for the effects on the antibacterial performance of the NFMs. Sequentially, a quaternization treatment has been employed on the NFMs with an optimal fibrous structure to enhance the antibacterial ability. The resulting quaternized NFMs have demonstrated the great biocidal effects against Gram-positive and Gram-negative bacteria. Moreover, the excellent biocompatibility of the quaternized NFMs have also been thoroughly evaluated and verified. This article is protected by copyright. All rights reserved.

Generating adipose stem cell-laden hyaluronic acid-based scaffolds using 3D bioprinting via the double crosslinked strategy for chondrogenesis

Bioprinting of most cell-laden hydrogel scaffolds with the required structural integrity, mechanical modulus, cell adhesion, cell compatibility, and chondrogenic differentiation are still significant issues that affect the application of bioinks in cartilage tissue engineering. This study focuses on constructing printable bioinks by combining adipose-derived stem cells (ADSCs), hyaluronic acid (HA)-based hydrogels and analyzing their ability to induce chondrogenesis using 3D bioprinting technology. First, biotinylated hyaluronic acid was synthesized via an adipic acid dihydrazide (ADH) linker with amide bond formation to form HA-biotin (HAB). Both HAB and the as-received streptavidin were mixed to form a partially cross-linked HA-biotin-streptavidin (HBS) hydrogel through noncovalent bonding. After that, the partially cross-linked HBS hydrogel was mixed with sodium alginate and subsequently printed to form the HBSA hydrogel 3D scaffolds using a bioprinter. Finally, the 3D scaffolds of the HBSA (HBS + alginate) hydrogel were submerged into CaCl₂ solution to achieve a stable 3D HBSAC (HBSA + Ca²⁺) hydrogel scaffold through ion transfer crosslinking. The physical-chemical characteristics of the hybrid bioink compositions have been evaluated to determine the desired 3D bioprinting structure. Cytotoxicity and chondrogenic differentiation were also assessed to confirm that the double cross-linked HBSAC hydrogel scaffold was useful for chondrogenic formation. The results showed that partially crosslinking the biotinylated HA-based hydrogel with streptavidin has a significant effect on printability and structural integrity. Morphological analysis of a suitable 3D printed HBSAC hydrogel scaffold showed visible pores with the desired shape and geometry. We have concluded that the HBSAC hydrogel possesses a favorable biocompatibility profile. The HBSAC hydrogel can also secrete significantly higher amounts of chondrogenic marker genes at day 5 and sulfated glycosaminoglycans (sGAGs) from days 7 to 14 compared to the HA hydrogel, as determined via quantitative real-time PCR assay and Alcian blue staining and the DMMB assay.

Increased vasculogenesis of endothelial cells in hyaluronic acid augmented fibrin-based natural hydrogels - from in vitro to in vivo models

Vascularisation efficiency plays an essential role in the success of bulk transplantation, while biocompatibility and safety are major concerns in clinical applications. Fibrin-based hydrogels have been exploited as scaffolds for their advantages in biocompatibility, degradability and mass transportation in various forms. However, the mechanical strength and degree of vascularisation remain unsatisfactory for clinical usage. An interpenetrating hydrogel was developed by adding hyaluronic acid (HA) to a fibrin-based natural hydrogel. The vasculogenesis of endothelial cells (human umbilical vein endothelial cells, HUVECs) was characterised within the gel using both in vitro and in vivo animal studies. The in vitro vascular morphology analysis showed 17.9 % longer mean tube length and 14.3 % higher average thickness in 7 d cultivation within the HA-supplemented hydrogel. The in vivo results showed 51.6 % larger total tube area, 1.8 × longer average tube length and 81.6 % higher cell number in the HA-supplemented hydrogel compared to the hydrogel without HA. The experimental results demonstrated better vascularisation and cell recruitment in the HA- supplemented hydrogel. The material properties of the hydrogels were also analysed using atomic force microscopy (AFM). The results revealed 3.7 × higher elasticity of the HA-supplemented hydrogel, which provided better mechanical strength and support for easy handling during procedures. With the demonstrated advantages, the developed hydrogels showed promise for exploitation in various practical clinical applications.

Humanized bispecific antibody (mPEG × HER2) rapidly confers PEGylated nanoparticles tumor specificity for multimodality imaging in breast cancer

Background

Developing a universal strategy to improve the specificity and sensitivity of PEGylated nanoaparticles (PEG-NPs) for assisting in the diagnosis of tumors is important in multimodality imaging. Here, we developed the anti-methoxypolyethylene glycol (mPEG) bispecific antibody (BsAb; mPEG × HER2), which has dual specificity for mPEG and human epidermal growth factor receptor 2 (HER2), with a diverse array of PEG-NPs to confer nanoparticles with HER2 specificity and stronger intensity.

Result

We used a one-step formulation to rapidly modify the nanoprobes with mPEG × HER2 and optimized the modified ratio of BsAbs on several PEG-NPs (Lipo-DiR, SPIO, Qdot and AuNP). The αHER2/PEG-NPs could specifically target MCF7/HER2 cells (HER2⁺⁺) but not MCF7/neo1 cells (HER2^+/−). The αHER2/Lipo-DiR and αHER2/SPIO could enhance the sensitivity of untargeted PEG-NPs on MCF7/HER2 (HER2⁺⁺). In in vivo imaging, αHER2/Lipo-DiR and αHER2/SPIO increased the specific targeting and enhanced PEG-NPs accumulation at 175% and 187% on 24 h, respectively, in HER2-overexpressing tumors.

Conclusion

mPEG × HER2, therefore, provided a simple one-step formulation to confer HER2-specific targeting and enhanced sensitivity and contrast intensity on HER2 positive tumors for multimodality imaging.

Combination of a Bioceramic Scaffold and Simvastatin Nanoparticles as a Synthetic Alternative to Autologous Bone Grafting

The fragile nature of porous bioceramic substitutes cannot match the toughness of bone, which limits the use of these materials in clinical load-bearing applications. Statins can enhance bone healing, but it could show rhabdomyolysis/inflammatory response after overdosing. In this study, the drug-containing bone grafts were developed from poly(lactic acid-co-glycolic acid)-polyethylene glycol (PLGA-PEG) nanoparticles encapsulating simvastatin (SIM) (SIM-PP NPs) loaded within an appropriately mechanical bioceramic scaffold (BC). The combination bone graft provides dual functions of osteoconduction and osteoinduction. The mechanical properties of the bioceramic are enhanced mainly based on the admixture of a combustible reverse-negative thermoresponsive hydrogel (poly(N-isopropylacrylamide base). We showed that SIM-PP NPs can increase the activity of alkaline phosphatase and osteogenic differentiation of bone marrow stem cells. To verify the bone-healing efficacy of this drug-containing bone grafts, a nonunion radial endochondral ossification bone defect rabbit model (N = 3/group) and a nonunion calvarial intramembranous defect Sprague Dawley (SD) rat model (N = 5/group) were used. The results indicated that SIM-PP NPs combined with BC can improve the healing of nonunion bone defects of the radial bone and calvarial bone. Therefore, the BC containing SIM-PP NPs may be appropriate for clinical use as a synthetic alternative to autologous bone grafting that can overcome the problem of determining the clinical dosage of simvastatin drugs to promote bone healing.

[Clinicopathologic features of drug-induced vanishing bile duct syndrome]

Vanishing bile duct syndrome (VBDS) manifests as progressive destruction and disappearance of the intrahepatic bile duct caused by various factors and cholestasis. VBDS associated with drug-induced liver injury (D-VBDS) is an important etiology of VBDS, and immune disorder or immune imbalance may be the main pathogenesis. According to its clinical symptoms, serological markers, and course of the disease, D-VBDS is classified into major form and minor form, and its clinical features are based on various pathomorphological findings. Its prognosis is associated various factors including regeneration of bile duct cells, number of bile duct injuries, level and range of bile duct injury, bile duct proliferation, and compensatory shunt of bile duct branches. This disease has various clinical outcomes; most patients have good prognosis after drug withdrawal, and some patients may experience cholestatic cirrhosis, liver failure, and even death. Due to the clinical manifestation and biochemical changes are similar to the primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC), it need to identify by clinical physician.

Evaluations of clinical-grade bone substitute-combined simvastatin carriers to enhance bone growth: In vitro and in vivo analyses

We demonstrated in a value-added study that the combination of calcium phosphate–based bone substitute (MaxiBone® bioceramics) and simvastatin/poly lactic- co-glycolic acid (SIMm) carriers which were fabricated by GMP pharmaceutical company and underwent our patterned double-emulsion technique can promote bone growth. The average size distribution of SIMm, the encapsulation efficacy, and the in vitro release profile of simvastatin in SIMm over 14 days were investigated in this study. Based on the results of Alizarin Red S staining and alkaline phosphatase activity, the released simvastatin of SIMm can effectively induce osteogenesis of bone marrow mesenchymal stem cells (D1 cells). In the non-union fracture model of animal study, the MaxiBone bioceramics group and MaxiBone bioceramics with SIMm group showed a significant increase in the percentages of new bone matrix compared with the control group and SIMm groups at the 8th and 10th weeks. Moreover, the MaxiBone bioceramics with SIMm group showed the strongest effect in new bone formation among these groups. We concluded that the calcium phosphate–based ceramics of MaxiBone combined with SIMm can accelerate osteogenic differentiation and bone growth in vitro and in vivo. Our results provide a proof of concept that SIMm can play as an osteoinductive material and the combination with bone substitutes with osteoconductive property effectively enhance bone growth, and this treatment is value added for clinical application, especially in the healing of large bone defects or non-union.

Graphical abstract. The clinical-grade calcium phosphate–based bone substitute combined SIM/PLGA/HAp microspheres were fabricated by GMP pharmaceutical company to promote bone growth in bone defect model of mice.

Rapid In Situ MRI Traceable Gel-forming Dual-drug Delivery for Synergistic Therapy of Brain Tumor

Preventing tumor recurrence after surgical resection of a brain tumor is a significant clinical challenge because current methods deliver chemotherapeutic agents in a rapid manner and are not effective against the residual tumor cells. To overcome this drawback, we report a simple method to prepare magnetic resonance imaging (MRI) traceable ultra-thermosensitive hydrogels with rapid gelation ability from aqueous solution within 4 s at 28 °C for hydrophilic (epirubicin, EPI) and hydrophobic (paclitaxel, PTX) drugs co-delivery with bovine serum albumin nanoparticles (BSA NPs) incorporation. The results showed the average survival of gliosarcoma-bearing (MBR 614 or U87) mice receiving BSA/PTX NPs incorporated hydrogel_Gd/EPI increased to 63 days or 69 days with no tumor recurrence observed. Our synergistic strategy presents a new approach to the development of a local drug delivery system for the prevention of brain tumor recurrence.

PLGA-linked alendronate enhances bone repair in diaphysis defect model

Alendronate (ALN) is known as an anti-resorptive drug for the treatment of osteoporosis. Recently, ALN was found to stimulate osteogenic differentiation in mesenchymal stem cells and enhance new bone formation in calvarial bone defects. Previous in vitro and in vivo studies found that the effective concentration of ALN was approximately 1-10   μm. In the present study, a poly (lactic-co-glycolic acid) (PLGA) cross-linked ALN (PLGA-ALN) with a short-term controlled-release property for local application to enhance bone repair was developed. An in vitro drug-release kinetic test showed that PLGA-ALN microspheres released an effective concentration (50-100 nm) of ALN for 9 days. The effect of PLGA-ALN on bone repair was tested in a rat femoral bone defect model. The biomechanical study results showed that the maximal strength, stiffness and energy absorption were significantly increased in the PLGA-ALN group compared with the PLGA group. The microstructure of the newly formed bone at the defect site was analysed using microcomputed tomography. The PLGA-ALN group significantly improved the trabecular bone volume at the defect site compared with the PLGA group. The fibril collagen and immunolocalized bone morphogenetic protein 2 were evident in the newly formed trabecular bone in the PLGA-ALN group. Local use of newly developed PLGA-ALN-enhanced bone repair was attributable to increasing bone matrix formation, which improved the ultrastructure of the newly formed bone and thus increased the biomechanical properties of the repaired bone. It is suggested that PLGA-ALN may be a potential bone graft substitute to enhance bone repair. Copyright © 2016 John Wiley & Sons, Ltd.

Combination of calcium sulfate and simvastatin-controlled release microspheres enhances bone repair in critical-sized rat calvarial bone defects

Most allogenic bone graft substitutes have only osteoconductive properties. Developing new strategies to improve the osteoinductive activity of bone graft substitutes is both critical and practical for clinical application. Previously, we developed novel simvastatin-encapsulating poly(lactic-co-glycolic acid) microspheres (SIM/PLGA) that slowly release simvastatin and enhance fracture healing. In this study, we combined SIM/PLGA with a rapidly absorbable calcium sulfate (CS) bone substitute and studied the effect on bone healing in critical-sized calvarial bone defects in a rat model. The cytotoxicity and cytocompatibility of this combination was tested in vitro using lactate dehydrogenase leakage and a cell attachment assay, respectively. Combination treatment with SIM/PLGA and the CS bone substitute had no cytotoxic effect on bone marrow stem cells. Compared with the control, cell adhesion was substantially enhanced following combination treatment with SIM/PLGA and the CS bone substitute. In vivo, implantation of the combination bone substitute promoted healing of critical-sized calvarial bone defects in rats; furthermore, production of bone morphogenetic protein-2 and neovascularization were enhanced in the area of the defect. In summary, the combination of SIM/PLGA and a CS bone substitute has osteoconductive and osteoinductive properties, indicating that it could be used for regeneration of bone in the clinical setting.

Aspartic acid-based modified PLGA-PEG nanoparticles for bone targeting: in vitro and in vivo evaluation

Nanoparticles (NP) that target bone tissue were developed using PLGA-PEG (poly(lactic-co-glycolic acid)-polyethylene glycol) diblock copolymers and bone-targeting moieties based on aspartic acid, (Asp)(n(1,3)). These NP are expected to enable the transport of hydrophobic drugs. The molecular structures were examined by (1)H NMR or identified using mass spectrometry and Fourier transform infrared (FT-IR) spectra. The NP were prepared using the water miscible solvent displacement method, and their size characteristics were evaluated using transmission electron microscopy (TEM) and dynamic light scattering. The bone targeting potential of the NP was evaluated in vitro using hydroxyapatite affinity assays and in vivo using fluorescent imaging in zebrafish and rats. It was confirmed that the average particle size of the NP was <200 nm and that the dendritic Asp3 moiety of the PLGA-PEG-Asp3 NP exhibited the best apatite mineral binding ability. Preliminary findings in vivo bone affinity assays in zebrafish and rats indicated that the PLGA-PEG-ASP3 NP may display increased bone-targeting efficiency compared with other PLGA-PEG-based NP that lack a dendritic Asp3 moiety. These NP may act as a delivery system for hydrophobic drugs, warranting further evaluation of the treatment of bone disease.

Synthesis and characterization of cationic polymeric nanoparticles as simvastatin carriers for enhancing the osteogenesis of bone marrow mesenchymal stem cells

Simvastatin (SIM) can increase osteoblast activity and enhance osteogenesis. However, some limitations of SIM have been noted, such as statin-associated rhabdomyolysis and its poor solubility in water. In this study, we fabricated new cationic nanoparticles (NPs) designed for the controlled release of hydrophobic SIM and endocytosis by cells with the aim of reducing the total required amount of SIM administered and enhancing the osteogenesis of bone marrow mesenchymal stem cells (BMSCs). New copolymers of bis(poly(lactic-co-glycolic acid)-phenylalanine-polyethylene glycol)-quaternary ammonium grafted diethyltriamine (bis(PLGA-phe-PEG)-qDETA; BPPD) were created using a diethyltriamine-quaternary ammonium (qDETA) moiety, hetero-bifunctional polyethylene glycol (COOH-PEG-NH2), phenylalanine (phe) and poly(lactic-co-glycolic acid) (PLGA). SIM encapsulated in BPPD NPs (SIM/BPPD) was fabricated using a water-miscible solvent. The size distributions of BPPD NPs and SIM/BPPD NPs, the encapsulation efficacy and the in vitro release profile of SIM in SIM/BPPD NPs over 6days were investigated. Based on the results of Alizarin Red S staining, alkaline phosphatase (ALP) activity assays and quantitative polymerase chain reaction (Q-PCR) results, we propose that SIM/BPPD NPs may induce osteogenesis in BMSCs by enhancing the expression of an osteogenic gene, which subsequently elevates ALP activity and mineralization, resulting in enhanced BMSC osteogenesis. These results suggest that the SIM/BPPD NPs may be used as hydrophobic drug carriers to reduce the total required amount of SIM administered and to provide an effective SIM release mechanism for enhancing BMSC osteogenesis. Surprisingly, BPPD NPs were also shown to have the ability to promote osteogenesis in BMSCs by enhancing the expression of osteogenic genes, especially osteocalcin (OC), and subsequently elevating ALP activity and mineralization.

Effects of longitudinal baffles on particles settling in a sedimentation basin

This study was conducted to evaluate the effects of longitudinal baffles on particles settling performance within a full-scale sedimentation basin with a flow rate of 1,000 m(3)/hr. Comparative experiments on turbidity removal efficiency and sludge deposit distribution were performed in longitudinally baffled and non-baffled sedimentation basins. The turbidity removal rate in the baffled sedimentation basin was observed to be higher than that in the non-baffled basin. In addition, the depth of the sludge deposit in the baffled sedimentation basin was approximately 20% less than that in the non-baffled sedimentation basin, and the sludge concentration was 10% higher. To explain these results and to further investigate the effects of longitudinal baffles, the authors performed computational fluid dynamics (CFD) simulation for both basin types. The results of this CFD simulation indicated that the flow, particularly near the outlet orifice, was more stable in the longitudinally baffled sedimentation basin. Moreover, it could be concluded that the longitudinal baffle enables a fully developed flow and is thus more effective for sedimentation.

Local delivery of controlled-release simvastatin/PLGA/HAp microspheres enhances bone repair

Statins are used clinically for reduction of cholesterol synthesis to prevent cardiovascular disease. Previous in vitro and in vivo studies have shown that statins stimulate bone formation. However, orally administered statins may be degraded during first-pass metabolism in the liver. This study aimed to prevent this degradation by developing a locally administered formulation of simvastatin that is encapsulated in poly(lactic-co-glycolic acid)/hydroxyapatite (SIM/PLGA/HAp) microspheres with controlled-release properties. The effect of this formulation of simvastatin on bone repair was tested using a mouse model of gap fracture bridging with a graft of necrotic bone. The simvastatin released over 12 days from 3 mg and 5 mg of SIM/PLGA/HAp was 0.03-1.6 μg/day and 0.05-2.6 μg/day, respectively. SIM/PLGA/HAp significantly stimulated callus formation around the repaired area and increased neovascularization and cell ingrowth in the grafted necrotic bone at week 2 after surgery. At week 4, both 3 mg and 5 mg of SIM/PLGA/HAp increased neovascularization, but only 5 mg SIM/PLGA/HAp enhanced cell ingrowth into the necrotic bone. The low dose of simvastatin released from SIM/PLGA/HAp enhanced initial callus formation, neovascularization, and cell ingrowth in the grafted bone, indicating that SIM/PLGA/HAp facilitates bone regeneration. We suggest that SIM/PLGA/HAp should be developed as an osteoinductive agent to treat osteonecrosis or in combination with an osteoconductive scaffold to treat severe bone defects.

Preparation of porous bioceramics using reverse thermo-responsive hydrogels in combination with rhBMP-2 carriers: in vitro and in vivo evaluation

Porous biphasic calcium phosphates (BCP) were fabricated using reverse thermo-responsive hydrogels with hydroxyapatite (HAp) and β-tricalcium (β-TCP) powder and planetary centrifugal mixer. This hydrogel mixture slurry will shrink and compress the HAp powder during the sintering process. The porous bioceramics are expected to have good mechanical properties after sintering at 1200°C. Reverse thermo-responsive hydrogels of poly[(N-isopropylacrylamide)-co-(methacrylic acid)] p(NiPAAm-MAA) were synthesized by free-radical cross-linking copolymerization, and their chemical properties were evaluated by nuclear magnetic resonance spectroscopy, infrared spectroscopy, and electrospray-ionization mass spectrometry. The lower critical solution temperature (LCST) of the hydrogel was determined using turbidity measurements. A thermogravimetric analysis was used to examine the thermal properties. The porous bioceramic properties were analyzed by X-ray diffraction, scanning electron microscopy, bulk density, compressive strength testing and cytotoxicity. The compressive strength and average porosity of the porous bioceramics were examined at approximately 6.8MPa and 66% under 10wt% p(NiPAAm-MAA)=99:1 condition. The ratio of HAp/β-TCP can adjust two different compositional behaviors during the 1200°C sintering process without resulting in cell toxicity. The (rhBMP-2)-HAp-PLGA carriers were fabricated as in our previous study of the double emulsion and drop-coating technique. Results of animal study included histological micrographs of the 1-mm defect in the femurs, with the rhBMP-2 carrier group, the bioceramic spacer group and the bioceramic spacer with rhBMP-2 carriers group showing better callus formation around the femur defect site than the control group. The optimal dual effects of the bone growth factors from osteoconductive bioceramics and osteoinductive rhBMP-2 carriers produced better bone formation.

Hyaluronan initiates chondrogenesis mainly via CD44 in human adipose-derived stem cells

Cell-matrix adhesion is one of the important interactions that regulates stem cell survival, self-renewal, and differentiation. Our previous report (Wu SC, Chang JK, Wang CK, Wang GJ, Ho ML. Biomaterials 31: 631–640, 2010) indicated that a microenvironment enriched with hyaluronan (HA) initiated and enhanced chondrogenesis in human adipose-derived stem cells (hADSCs). We further hypothesize that HA-induced chondrogenesis in hADSCs is mainly due to the interaction of HA and CD44 (HA-CD44), a cell surface receptor of HA. The HA-CD44 interaction was tested by examining the mRNA expression of hyaluronidase-1 (Hyal-1) and chondrogenic marker genes (SOX-9, collagen type II, and aggrecan) in hADSCs cultured on HA-coated wells. Cartilaginous matrix formation, sulfated glycosaminoglycan, and collagen productions by hADSCs affected by HA-CD44 interaction were tested in a three-dimensional fibrin hydrogel. About 99.9% of hADSCs possess CD44. The mRNA expressions of Hyal-1 and chondrogenic marker genes were upregulated by HA in hADSCs on HA-coated wells. Blocking HA-CD44 interaction by anti-CD44 antibody completely inhibited Hyal-1 expression and reduced chondrogenic marker gene expression, which indicates that HA-induced chondrogenesis in hADSCs mainly acts through HA-CD44 interaction. A 2-h preincubation and coculture of cells with HA in hydrogel (HA/fibrin hydrogel) not only assisted in hADSC survival, but also enhanced expression of Hyal-1 and chondrogenic marker genes. Higher levels of sulfated glycosaminoglycan and total collagen were also found in HA/fibrin hydrogel group. Immunocytochemistry showed more collagen type II, but less collagen type X, in HA/fibrin than in fibrin hydrogels. Our results indicate that signaling triggered by HA-CD44 interaction significantly contributes to HA-induced chondrogenesis and may be applied to adipose-derived stem cell-based cartilage regeneration.

Electromagnetic fields enhance chondrogenesis of human adipose-derived stem cells in a chondrogenic microenvironment in vitro

We tested the hypothesis that electromagnetic field (EMF) stimulation enhances chondrogenesis in human adipose-derived stem cells (ADSCs) in a chondrogenic microenvironment. A two-dimensional hyaluronan (HA)-coated well (2D-HA) and a three-dimensional pellet culture system (3D-pellet) were used as chondrogenic microenvironments. The ADSCs were cultured in 2D-HA or 3D-pellet, and then treated with clinical-use pulse electromagnetic field (PEMF) or the innovative single-pulse electromagnetic field (SPEMF) stimulation. The cytotoxicity, cell viability, and chondrogenic and osteogenic differentiations were analyzed after PEMF or SPEMF treatment. The modules of PEMF and SPEMF stimulations used in this study did not cause cytotoxicity or alter cell viability in ADSCs. Both PEMF and SPEMF enhanced the chondrogenic gene expression (SOX-9, collagen type II, and aggrecan) of ADSCs cultured in 2D-HA and 3D-pellet. The expressions of bone matrix genes (osteocalcin and collagen type I) of ADSCs were not changed after SPEMF treatment in 2D-HA and 3D-pellet; however, they were enhanced by PEMF treatment. Both PEMF and SPEMF increased the cartilaginous matrix (sulfated glycosaminoglycan) deposition of ADSCs. However, PEMF treatment also increased mineralization of ADSCs, but SPEMF treatment did not. Both PEMF and SPEMF enhanced chondrogenic differentiation of ADSCs cultured in a chondrogenic microenvironment. SPEMF treatment enhanced ADSC chondrogenesis, but not osteogenesis, when the cells were cultured in a chondrogenic microenvironment. However, PEMF enhanced both osteogenesis and chondrogenesis under the same conditions. Thus the combination of a chondrogenic microenvironment with SPEMF stimulation can promote chondrogenic differentiation of ADSCs and may be applicable to articular cartilage tissue engineering.

Assessment of reinforced poly(ethylene glycol) chitosan hydrogels as dressings in a mouse skin wound defect model

Wound dressings of chitosan are biocompatible, biodegradable, antibacterial and hemostatic biomaterials. However, applications for chitosan are limited due to its poor mechanical properties. Here, we conducted an in vivo mouse angiogenesis study on reinforced poly(ethylene glycol) (PEG)-chitosan (RPC) hydrogels. RPC hydrogels were formed by cross-linking chitosan with PEGs of different molecular weights at various PEG to chitosan ratios in our previous paper. These dressings can keep the wound moist, had good gas exchange capacity, and was capable of absorbing or removing the wound exudate. We examined the ability of these RPC hydrogels and neat chitosan to heal small cuts and full-thickness skin defects on the backs of male Balb/c mice. Histological examination revealed that chitosan suppressed the infiltration of inflammatory cells and accelerated fibroblast proliferation, while PEG enhanced epithelial migration. The RPC hydrogels promoted wound healing in the small cuts and full layer wounds. The optimal RPC hydrogel had a swelling ratio of 100% and a water vapor transmission rate (WVTR) of about 2000 g/m(2)/day. In addition, they possess good mechanical property and appropriate degradation rates. Thus, the optimal RPC hydrogel formulation functioned effectively as a wound dressing and promoted wound healing.

The effect of the local delivery of alendronate on human adipose-derived stem cell-based bone regeneration

Recent studies have shown that alendronate (Aln) enhances the osteogenesis of osteoblasts and bone marrow mesenchymal stem cells. In this study, we hypothesize that Aln may act as an osteo-inductive factor to stimulate the osteogenic differentiation of human adipose-derived stem cells (hADSCs) for bone regeneration. The in vitro effect of Aln (1-10 μM) on the osteogenic ability of hADSCs was evaluated by examining mineralization and alkaline phosphatase (ALP) activity. Bone morphogenetic protein 2 (BMP2) expression was measured using a real-time polymerase chain reaction and western blot analysis. Our results indicated that 5 μM Aln was sufficient to enhance BMP2 expression, ALP activity and mineralization in hADSCs. The in vivo effect of locally administered Aln on bone repair was examined in a rat critical-sized (7-mm) calvarial defect that was implanted with a hADSC-seeded poly(lactic-co-glycolic acid) (PLGA) scaffold. Aln (5 μM/100 μl/day) was injected locally into the defect site for one week. New bone formation was evaluated by radiographic and histological analyses at 8 and 12 weeks post-implantation. The expression levels of human BMP2 (hBMP2) and hADSC localization in defect sites were examined using immunohistochemistry analysis and fluorescent in situ hybridization, respectively. Results showed that local treatment of Aln on hADSC-seeded PLGA scaffolds at week 12 had a maximal effect on bone regeneration, enhancing mineralization and bone matrix formation. In addition, hADSCs and hBMP2 were also detected at the defect sites. These results demonstrated that local delivery of Aln, a potent osteo-inductive factor, enhances hADSC osteogenesis and bone regeneration.

Fern plant-derived protoapigenone leads to DNA damage, apoptosis, and G(2)/m arrest in lung cancer cell line H1299

Protoapigenone, isolated from the native fern plant Thelypteris torresiana, has anticancer activity against some cancer cells. However, the toxicological mechanism for protoapigenone is still unknown. Here, we investigated the anticancer effect of protoapigenone on human lung cancer cell lines. The comet assay showed that DNA damage induced by protoapigenone is dose-dependent. Trypan blue exclusion showed that the cell killing by protoapigenone is both time and dose dependent. The IC(50) of protoapigenone for 12, 24, and 48 h in H1299 cells is 6.11, 2.74, and 1.49 microM, respectively. Flow cytometry showed cell cycle perturbation such as sub-G(1) accumulation (at 1.57 microM for 48 h and at 3.57 microM for 12 and 24 h) and G(2)/M arrest (at 3.57 microM for 12 and 24 h) for protoapigenone. The sub-G(1) accumulation phenomena in the 3.57 microM for 24 h sample were shown to be apoptosis using Annexin V-immunofluorescence/propidium iodide staining. These results suggest protoapigenone is a potential chemotherapeutic agent for lung cancers.

Enhancement of chondrogenesis of human adipose derived stem cells in a hyaluronan-enriched microenvironment

Microenvironment plays a critical role in guiding stem cell differentiation. We investigated the enhancing effect of a hyaluronan (HA)-enriched microenvironment on human adipose derived stem cell (hADSC) chondrogenesis for articular cartilage tissue engineering. The hADSCs were obtained from patients undergoing hip replacement. HA-coated wells and HA-modified poly-(lactic-co-glycolic acid) (HA/PLGA) scaffolds were used as the HA-enriched microenvironment. The mRNA expressions of chondrogenic (SOX-9, aggrecan and collagen type II), fibrocartilage (collagen type I), and hypertrophic (collagen type X) marker genes were quantified by real-time polymerase chain reaction. Sulfated glycosaminoglycan (sGAG) deposition was detected by Alcian blue, safranin-O staining, and dimethylmethylene blue (DMMB) assays. Localized collagen type II was detected by immunohistochemistry. The hADSCs cultured in HA-coated wells (0.005-0.5 mg/cm(2)) showed enhanced aggregation and mRNA expressions (SOX-9, collagen type II, and aggrecan) after 24h, and sGAG content was also significantly increased after 9 days of culture. The HA-modified PLGA did not change the cell adherence and viability of hADSCs. The mRNA expressions of chondrogenic marker genes were significantly enhanced in hADSCs cultured in HA/PLGA rather than those cultured in the PLGA scaffold after 1, 3, and 5 days of culture. The hADSCs cultured in HA/PLGA produced higher levels of sGAG and collagen type II, compared to those in the PLGA scaffold after 4 weeks of cultures. Our results suggest that HA-enriched microenvironment induces chondrogenesis in hADSCs, which may be beneficial in articular cartilage tissue engineering.

Deriving fast setting properties of tetracalcium phosphate/dicalcium phosphate anhydrous bone cement with nanocrystallites on the reactant surfaces

OBJECTIVE

This study attempts to reveal how nanocrystallites on the ceramic surfaces of non-dispersive calcium phosphate cement (nd-CPC) participate in setting processes as compared with conventional CPC (c-CPC).

METHODS

The compositions and morphologies of CPC during the early setting reactions were studied with X-ray diffraction and a scanning transmission electron microscope equipped with an energy dispersive spectroscopy system. The pH values and dispersive properties of CPC during the early setting reactions were investigated as well as the compressive strength of nd-CPC after 24h of immersion with varying liquid to powder ratios.

RESULTS

The mechanical strength of nd-CPC was approximately 60MPa after a 24h immersion in simulate body solution with a P/L ratio between 3.3 and 4.2g/mL. The nanocrystallites on the particle surfaces of nd-CPC were shown to grow rapidly and provided interlocking sites that allowed rapid development of the apatite phase in the cement, and were also shown to be non-dispersive in solution as determined by an injection test of c-CPC.

CONCLUSIONS

The interlocking particles produced by whisker growth on the ceramic particles or new crystallites formed between the ceramic particles caused the cement to be non-dispersive in solution. The particles of reactants with nanocrystallites on surfaces also gave this cement the ability to be shaped easily as a paste during an operation or to be injected into a cavity.

Melamine contamination

In the summer of 2008, serious illnesses and deaths of babies in China were linked to melamine-tainted powdered infant formula. Melamine contains several metabolites, such as ammeline, ammelide, and cyanuric acid, and has been used for the adulteration of foods or milk to increase their apparent protein content. It is assumed that melamine and its metabolites are absorbed in the gastrointestinal tract, and precipitate in the kidney to form crystals. A new tolerable daily intake of 0.2 mg kg(-1) body weight was adapted by the World Health Organization in 2008. This paper reviews the variety of analytical methods that have been used for the analysis of melamine in food. The limit of detection of these various methods is 0.05-100 ppm. The maximum acceptable concentration in food has been set at 50 ppb by the US FDA. A fast and ultrasensitive procedure for screening, detection, and characterization of melamine and its derivative compounds needs to be established. Currently, mass-spectrometry technologies provide an alternative to derivatization for regulatory analysis of food.

Controlled-release of rhBMP-2 carriers in the regeneration of osteonecrotic bone

Untreated osteonecrosis of the hip causes collapse of the femoral head and eventually leads to the development of premature degenerative arthritis. In order to reverse this late complication after the core decompression procedure, we studied three different types of carriers used to entrap recombinant human bone morphogenetic protein-2 (rhBMP-2) in terms of their performance in osteonecrosis regeneration and creeping substitution in Balb/C mice. The rhBMP-2 was loaded into PLGA-HAp microsphere in three different ways. We first verified the therapeutic dose in vitro using D1 and C2C12 cells. Then the individual performance of the three carrier preparations in vivo was examined by soft X-ray observation, histological analysis and immunostaining of bone tissue. In addition, the BMP-2 protein concentration activity in the serum was monitored. The results revealed that the bioactivity of rhBMP-2 released from a carrier with an ideal therapeutic dose was well maintained; this eventually helped to improve the healing and substitution of necrotic bone in vivo. These observations demonstrate that the in vivo performance of these newly developed rhBMP-2 delivery carriers correlates well with their in vitro release profiles. We concluded that sustained controlled-release of rhBMP-2 above a therapeutic dose could not only induce early callus wrapping of the necrotic bone but also produce neovascularization and substitution inside of the dead bone.

Optimized bone regeneration based on sustained release from three-dimensional fibrous PLGA/HAp composite scaffolds loaded with BMP-2

Contemporary treatment of critical bone defect remains a significant challenge in the field of orthopedic surgery. Engineered biomaterials combined with growth factors have emerged as a new treatment alternative in bone repair and regeneration. Our approach is to encapsulate bone morphogenetic protein-2 (BMP-2) into a polymeric matrix in different ways and characterize their individual performance in a nude mouse model. The main objective of this study is to examine whether the PLGA/HAp composite fibrous scaffolds loaded with BMP-2 through electrospinning can improve bone regeneration. The hypothesis is that different loading methods of BMP-2 and different HAp contents in scaffolds can alternate the release profiles of BMP-2 in vivo, therefore modify the performance of scaffolds in bone regeneration. Firstly, mechanical strength of scaffolds and HAp nanoparticles distribution in scaffolds were investigated. Secondly, nude mice experiments extended to 6 weeks were carried out to test the in vivo performance of these scaffolds, in which measurements, like serum BMP-2 concentration, ALP activity, X-ray qualification, and H&E/IHC tissue staining were utilized to monitor the growth of new bone and the changes of the corresponding biochemical parameters. The results showed that the PLGA/HAp composite scaffolds developed in this study exhibited good morphology/mechanical strength and HAp nanoparticles were homogeneously dispersed inside PLGA matrix. Results from the animal experiments indicate that the bioactivity of BMP-2 released from the fibrous PLGA/HAp composite scaffolds is well maintained, which further improves the formation of new bone and the healing of segmental defects in vivo. It is concluded that BMP-2 loaded PLGA/HAp composite scaffolds are promising for bone healing.

Quantitative analysis of changes in endometrial gland morphology during the bovine oestrous cycle and their association with progesterone levels

This study describes a digital technique for uterine morphometry and its application to endometrial structure during the bovine oestrous cycle. Neither the number nor the size of uterine gland ducts changed during the cycle but a reduction in total endometrial area from days 0 to 8 after oestrus led to an increase in the proportion of the endometrium occupied by gland ducts (gland duct density). This effect on day 8 was maintained to day 16. When endometrial morphology was related to circulating progesterone concentrations on days 5 and 8 of the luteal phase, no relationships were found on day 5, but on day 8, a high progesterone concentration was associated with an increased number of gland ducts. Furthermore, in animals slaughtered on day 8, a high progesterone concentration on day 5 was associated with decreased gland duct size, though a simultaneous decrease in endometrial area led to an increase in gland duct density. The results suggest that contrary to expectation, endometrial glands do not grow and regress during the oestrous cycle, although cyclic changes in endometrial area controlled by progesterone lead to changes in gland duct density.

Optimal skin surface landmark for the SVC-RA junction in cancer patients requiring the implantation of permanent central venous catheters

We compared four different skin surface landmarks, the lower margin of the right 2nd costo-sternal junction (point A); the upper margin of the right 3rd costo-sternal junction (point B); the lower margin of the right 3rd costo-sternal junction (point C); and a point 5 cm below the manubrio-sternal junction (point D), in 20 cancer patients undergoing insertion of permanent central venous catheters whose tips were placed near the superior vena cava - right atrium (SVC-RA) junction under transoesophageal echocardiography guidance. The landmark was satisfactory if it was located within 1 cm of the SVC-RA junction. Points C and D were closer to the SVC-RA junction than points A and B (p < 0.0001). However, point C had the highest incidence (C: 70%, A: 0%, B: 20%, D: 30%, p < 0.0001) of being within 1 cm of the SVC-RA junction.

Differential Dysfunction of Dendritic Cells and B-cells During Chronic HCV Infection (46.11)

Chronic hepatitis C virus (HCV) infection is characterized by attenuated antiviral T cell responses. We hypothesized that HCV-associated dysfunction of antigen presenting cells (APC) may be responsible, in part, for such attenuation. We evaluated the function and phenotype of dendritic cells (myeloid vs. plasmacytoid), B cells, and monocytes, finding distinct functional differences among the APC subsets. Myeloid DC (MDC) from chronic HCV patients showed slightly lower APC capacity with lower HLA-DR and CD86 expression. HCV-MDC also had a tendency to secrete more IL-10, when compared to healthy MDC. On the other hand, HCV-plasmacytoid DC (PDC) showed a significantly reduced ability to make IFN-α. B cells from HCV patients had a hyperactivated phenotype and a marked enhanced APC capacity. Interestingly, the enhanced B cell APC function correlated with detection of virus in these cells. Finally, increased APC functionality was paradoxically associated with the generation of a higher proportion of induced regulatory T-cells, providing a plausible explanation for T-cell attenuation. In conclusion, our studies underscore the necessity to dissect APC subsets for functional perturbations and provide evidence for their role in the immune attenuation accompanying chronic HCV infection.

Modeling of particle removal in the first coarse media of direct horizontal-flow roughing filtration

Horizontal-Flow Roughing Filtration (HRF) is an alternative pretreatment method e.g. prior to Slow Sand Filtration (SSF). However, some of its limitations are that the effluent quality drops drastically at higher turbidity (>200NTU) and at higher filtration rate (>1 m h(-1)). To overcome these drawbacks, we suggested Direct Horizontal-Flow Roughing Filtration (DHRF), which is a modified system of Horizontal-Flow Roughing Filtration (HRF) by addition of a low dose of coagulant prior to filtration. To optimize the DHRF configuration, a conceptual and mathematical model for the coarse compartment has been developed in analogy with multi-plate settler. Data from simple column settling test can be used in the model to predict the filter performance. Furthermore, the model developed herein has been validated by successive experiments. The conventional column settling test has been found to be handy and useful to predict the performance of DHRF for different raw water characteristics (e.g. coagulated or uncoagulated water, different amounts of organic matter, etc.) and different initial process conditions (e.g. coagulant dose, mixing time and intensity, etc.). An optimum filter design for the coarse compartment (grain size 20 mm) has been found to be of 3m h(-1) filtration rate with filter length of 4-4.5 m.

Design and simulation of a GEM-based TEPC as a neutron REM meter

A new plate-like tissue equivalent proportional counter (TEPC) based on the gas electron multiplier (GEM) is being developed for use as a neutron rem meter. The advantage of a plate-like TEPC over a conventional spherical TEPC is that several of the plate-like TEPCs can be stacked together as one unit to increase sensitivity to neutrons. A GEM-based TEPC consists of four layers of materials in a series: the front cover made of polyethylene, the cathode made of A-150 plastic, the gas region containing 1/3 atm of P-10 and 1/3 atm of nitrogen and the anode made of a copper-coated printed circuit board. The dimensions of the TEPC are 10 cm x 10 cm x 1.8 cm. The computer simulation shows that the neutron response function of the TEPC closely resembles the response curve of H(10) for neutrons with energies between 0.25 eV and 10 MeV. The corresponding sensitivity for such a TEPC for a bare (252)Cf neutron source was calculated to be 5.0 cpm per microSv h(-1). This sensitivity can be increased many times by simply stacking several TEPCs together as one unit.

Transient regulatory T-cells: a state attained by all activated human T-cells

CD4(+)CD25(+)FOXP3(+) regulatory T-cells (T(regs)) form an important arm of the immune system responsible for suppressing untoward immune responses. T(regs) can be thymically derived or peripherally induced, even from CD4(+)CD25(-)FOXP3(-) T-cells. FOXP3 expression and in vitro suppressive activity are considered unique hallmarks of this dedicated and stable lineage of regulatory cells. Here we show that virtually all human CD4(+)CD25(-)FOXP3(-) T-cells and CD8(+)CD25(-)FOXP3(-) T-cells attain a transient FOXP3(+)CD25(+) state during activation. In this state of activation, these cells possess the classic phenotype of T(regs), in that they express similar markers and inhibit in vitro proliferation of autologous CD4(+)CD25(-) T-cells. This state is characterized by suppressed IFN-gamma production and robust TNF-alpha and IL-10 production. Interestingly, the great majority of the activated cells eventually downregulate FOXP3 expression, with a concomitant drop in suppressive ability. Our results show that, in humans, FOXP3 expression and T(reg) functionality are not exclusive features of a stable or unique lineage of T-cells but may also be a transient state attained by almost all T-cells. These results warrant caution in interpreting human studies using FOXP3 and suppressive activity as readouts and suggest that attempts to induce "T(regs)" may paradoxically result in induction of effector T-cells, unless stability is confirmed.

Interactions between the cytomegalovirus promoter and the estrogen response element: implications for design of estrogen-responsive reporter plasmids

We aimed to produce an estrogen-responsive reporter plasmid that would permit monitoring of estrogen receptor function in the uterus in vivo. The plasmid pBL-tk-CAT(+)ERE was induced by estrogen in bovine endometrial stromal cells. When the CAT gene was replaced by the secreted alkaline phosphatase SeAP, the resulting construct pBL-tk-SeAP(+)ERE remained estrogen responsive. However when the tk promoter was replaced by the cytomegalovirus (cmv) promoter, the resulting plasmid (pBL-cmv-SeAP(+)ERE) was not estrogen responsive. Inhibition of ERE function was not due to an effect in trans or due to lack of estrogen receptor. It was not due to an interaction between the cmv promoter and the SeAP gene. cmv promoter function was dependent on NF-kappaB, and mutagenesis in the NF-kappaB sites reduced basal reporter expression without imparting responsiveness to estrogen. A mutation in the TATA box also failed to impart estrogen responsiveness. Modeling of DNA accessibility indicated the ERE was inserted at a site accessible to transcription factors. We conclude that the cmv promoter inhibits ERE function in cis when the two sequences are located in the same construct, and that this effect does not involve an interaction between cmv and reporter gene, NF-kappaB sites or the TATA box, or DNA inaccessibility.