Coaxial nanofibers encapsulated with Ampelopsis brevipedunculata extract and green synthesized AgNPs for wound repair.

Silver nanoparticles (AgNPs) synthesized from Aloe vera extract exhibited a pronounced antibacterial effect, while the Ampelopsis brevipedunculata extract (ABE) showcased a high antioxidant capacity for wound healing. Spherical AgNPs with a particle size of 28.82 nm crystallized in a face-centered-cubic lattice. AgNPs/polyvinyl alcohol (PVA) and ABE/polycaprolactone (PCL) underwent electrospinning to produce coaxial and electrosprayed nanofibers, respectively. The developed coaxial nanofibers demonstrated a strain of 159%, a Young's modulus of elasticity of 7080.14 kPa, a 3.9-fold swelling ratio, a water contact angle of 38.91°, characteristic hydrophilicity, and an adequate water vapor transmission rate of 2272 g/m2/day. ABE exhibited no cytotoxicity to L929 cells and induced a twofold increase in the cell migration rate. Upon applying the developed coaxial nanofiber on an in vivo rat model with a 9 mm wound diameter, the wound rapidly and completely healed within 10 days, with a healing speed 60% greater than that of the control group. Histopathological analysis revealed that the coaxial group did not exhibit inflammation, showed complete epithelization, and featured a well-arranged deposition of collagen on the 10th day.

Sprayable hydroxypropyl chitin/collagen extract of Ampelopsis brevipedunculata hydrogel accelerates wound healing.

OBJECTIVE: Keeping a wound moist can allow effective and rapid healing, and it can control the formation of scabs, thereby allowing cell proliferation and epithelial formation. When regularly changing a dressing, thermosensitive hydrogel as a moist dressing does not cause a secondary wound from adhesion. The main aim of this study was to evaluate the effect of a new sprayable thermosensitive hydrogel on wound healing. METHOD: The hydrophobic N-acetyl group of chitin was removed by microwave reaction with lye until the degree of acetylation was 60%, followed by reaction with propylene oxide to obtain hydroxypropyl chitin (HPCH) with a degree of substitution of 40%. After mixing HPCH with fish scale collagen (FSC), a thermosensitive hydrogel with a gel temperature of 26.5°C was obtained. Ampelopsis brevipedunculata extracts (ABE), which have been found to accelerate wound repair and improve healing, were added. HPCH/FSC is not toxic to the mouse L929 cell line and forms a hydrogel at body surface temperature. It can be easily sprayed on a wound. The HPCH/FSC has a three-dimensional network porous structure with a swelling ratio of 10.95:1 and a water vapour transmission rate of 2386.03±228.87g/m2/day; it can facilitate the penetration of water and air, and promote absorption of wound exudate. Wound repair was performed on five Sprague-Dawley rats. Each rat had three wounds, which were treated with medical gauze, HPCH/FSC and HPCH/FSC/ABE, respectively. RESULTS: The wounds in the HPCH/FSC/ABE group recovered the fastest in vivo, the mature wound site was smoother, the re-epithelialisation was even and thicker, and the angiogenesis developed rapidly to the mature stage. CONCLUSION: In this study, HPCH/FSC/ABE thermosensitive hydrogel was shown to effectively accelerate wound healing and was convenient for practical application.

Achyranthes bidentate extracts protect the IL-1ß-induced osteoarthritis of SW1353 chondrocytes.

Osteoarthritis, the most common joint disease worldwide, is a degenerative disease characterized by cartilage degeneration and inflammation. The active ingredients in the traditional Chinese medicinal plant Achyranthes bidentate can be used to treat waist, leg, and joint pain caused by rheumatism arthralgia. In this study, we identified the optimal microwave extraction protocol for saponins from A. bidentate, evaluated their protective effects against IL-1ß-induced inflammation in SW1353 human chondrocytes, and explored their protective pathway. The microwave-extraction parameters required to obtain the maximum yield of A. bidentate saponins using 80% ethanol were identified using response surface methodology. The parameters were solid-liquid ratio, 1:10; extraction time, 20 min; power, 721 W; temperature, 65 °C. The actual yield of saponins extracted was to be 194.01 µg/mg extract. The SW1353 cells were pretreated with A. bidentate extract (ABE) at a concentration of 50 or 100 µg/mL for 3 h, after which an inflammatory response was stimulated using IL-1ß. The ABE significantly reduced the expression of proinflammatory factors IL-6, TNF-α, COX-2, iNOS, PGE2, and NO, and inhibited NF-κB activity, effectively attenuating the inflammatory response. ABE also inhibited MMP13 and ADAMTS-5 expression, reducing IL-1ß-induced degradation of the extrachondral matrix. This confirmed that ABE effectively inhibits NF-κB activity and reduces IL-1ß-induced inflammation, extracellular matrix degradation, and expression of apoptotic proteins Bax and caspase-3. Therefore, ABE has potential as a new botanical drug for preventing osteoarthritis.

Effects of Organic Elicitors on the Recycled Production of Ginkgolide B in Immobilized Cell Cultures of Ginkgo biloba.

Ginkgo biloba is a medicinal plant used in complementary and alternative medicines. Ginkgo biloba extracts contain many compounds with medical functions, of which the most critical is ginkgolide B (GB). The major role that GB plays is to function as an antagonist to the platelet-activating factor, which is one of the causes of thrombosis and cardiovascular diseases. Currently, GB is obtained mainly through extraction and purification from the leaves of Ginkgo biloba; however, the yield of GB is low. Alternatively, the immobilized cultivation of ginkgo calluses with biomaterial scaffolds and the addition of organic elicitors to activate the cell defense mechanisms were found to stimulate increases in GB production. The aim of this study was to use Ginkgo biloba calluses for immobilized cultures with different elicitors to find a more suitable method of ginkgolide B production via a recycling process.

Therapeutic Potential of Pretreatment with Exosomes Derived from Stem Cells from the Apical Papilla against Cisplatin-Induced Acute Kidney Injury.

Acute kidney injury (AKI) is the most serious side effect of treatment with cisplatin in clinical practice. The aim of this study was to investigate the therapeutic effect of exosomes derived from stem cells from the apical papilla (SCAPs) on AKI. The medium from a SCAP culture was collected after 2 d of culture. From this, SCAP-derived exosomes (SCAP-ex), which were round (diameter: 30-150 nm) and expressed the characteristic proteins CD63 and CD81, were collected via differential ultracentrifugation. Rat renal epithelial cells (NRK-52E) were pretreated with SCAP-ex for 30 min and subsequently treated with cisplatin to induce acute injury. The extent of oxidative stress, inflammation, and apoptosis were used to evaluate the therapeutic effect of SCAP-ex against cisplatin-induced nephrotoxicity. The viability assay showed that the survival of damaged cells increased from 65% to 89%. The levels of reactive oxygen species decreased from 176% to 123%. The glutathione content increased by 78%, whereas the levels of malondialdehyde and tumor necrosis factor alpha (TNF-α) decreased by 35% and 9%, respectively. These results showed that SCAP-ex can retard oxidative stimulation in damaged kidney cells. Quantitative reverse transcription-polymerase chain-reaction gene analysis showed that they can also reduce the expression of nuclear factor-κß (NF-κß), interleukin-1ß (IL-1ß), and p53 in AKI. Further, they increased the gene expression of antiapoptotic factor B-cell lymphoma-2 (Bcl-2), whereas they reduced that of proapoptotic factors Bcl-2-associated X (Bax) and caspase-8 (CASP8), CASP9, and CASP3, thereby reducing the risk of cell apoptosis.

Biological and Cytoprotective Effect of Piper kadsura Ohwi against Hydrogen-Peroxide-Induced Oxidative Stress in Human SW1353 Cells.

Oxidative stress plays a role in regulating a variety of physiological functions in living organisms and in the pathogenesis of articular cartilage diseases. Piper kadsura Ohwi is a traditional Chinese medicine that is used as a treatment for rheumatic pain, and the extracts have anti-inflammatory and antioxidant effects. However, there is still no study related to cell protection by P. kadsura. The P. kadsura extracts (PKE) were obtained by microwave-assisted extraction, liquid-liquid extraction, and column chromatography separation. The extracts could effectively scavenge free radicals in the antioxidant test, the EC50 of extracts is approximately the same as vitamin C. PKE decreased the apoptosis of SW1353 cells treated with H2O2 and could upregulate the gene expression of antioxidant enzymes (SOD-2, GPx, and CAT) and the Bcl-2/Bax ratio, as well as regulate PARP, thus conferring resistance to H2O2 attack. PKE protects cells against apoptosis caused by free radicals through the three pathways of JNK, MEK/ERK, and p38 by treatment with MAPK inhibitor. The identified components of PKE were bicyclo [2.2.1] heptan-2-ol-1,7,7-trimethyl-,(1S-endo)-, alpha-humulene, and hydroxychavicol by gas chromatography-mass spectrometry.

Polycaprolactone/Polyethylene Glycol Blended with Dipsacus asper Wall Extract Nanofibers Promote Osteogenic Differentiation of Periodontal Ligament Stem Cells.

Dipsacus asper wall (DA) is an ancient Chinese medicinal material that has long been used to maintain the health of human bones. The present study aimed to evaluate the osteogenic differentiation of periodontal ligament stem cells (PDLSCs) of Dipsacus asper wall extracts (DAE). Microwave-assisted alcohol extraction of 100 mesh DA powder under optimal conditions can obtain 58.66% (w/w) yield of the crude extract. PDLSCs have excellent differentiation potential. PDLSCs treated with DA extract (DAE) underwent osteogenesis, exhibiting a higher expression of the Col-1, ALP, Runx2, and OCN genes, and had a 1.4-fold increase in mineralization, demonstrating the potential of DAE to promote osteogenic differentiation. After the addition of PI3K inhibitor LY294002, the expression of osteogenic genes was significantly inhibited, confirming that PI3K is an important pathway for DAE to induce osteogenesis. Mix DAE with polycaprolactone/polyethylene glycol (PCL/PEO) to obtain nanofibers with a diameter of 488 nm under optimal electrospinning conditions. The physical property analysis of nanofibers with and without DAE includes FTIR, mechanical strength, biodegradability, swelling ratio and porosity, and cell compatibility. When cells induced by nanofibers with or without DAE, the mineralization of PDLSCs cultured on PCL/PEO/DAE was 2.6-fold higher than that of PCL/PEO. The results of the study confirm that both DAE and PCL/PEO nanofibers have the effect of promoting osteogenic differentiation. In order to obtain the best induction effect, the optimal amount of DAE can be discussed in future research.

Phosphorylation of levan by microwave-assisted synthesis enhanced anticancer ability.

Levan is an exopolysaccharide produced by Bacillus licheniformis (strain FRI MY-55) that shows promising pharmacological activity. Phosphorylation is a chemical modification that can increase the biological and antioxidant properties of levan. In this study, levan was phosphorylated by microwave-assisted synthesis to achieve a degree of substitution of 0.29. The hydroxyl radical scavenging activity of microwave-assisted phosphorylated levan (microwave P) increased significantly (6-fold) over native levan; this activity was only slightly lower than vitamin C. Other free radical scavenging and reducing power tests revealed that Microwave P activity was increased by 30-40%. Microwave P inhibited the proliferation of HCT-116 and A549 cancer cell lines more readily than native levan with an IC50 of 1.03 mg/mL and 1.38 mg/mL for HCT-116 and A549 cells, respectively. Cells treated with native levan and its derivatives remained in the sub-G1 phase according to cell cycle analysis, whereas Microwave P treatment increased the proportion of cells undergoing apoptosis. Furthermore, Microwave P effectively upregulated pro-apoptosis marker Bax and downregulated anti-apoptosis marker Bcl-2, in addition to inducing the expression of caspase-9 and caspase-3. These findings show that levan phosphorylated via microwave-assisted synthesis showed increased antioxidant and antitumor activity over native levan or levan phosphorylated via traditional long-term heating. In particular, Microwave P possesses antiproliferative activity and can induce apoptosis through mitochondrial pathways in cancerous cells.

A study of the differentiation of stem cells from human exfoliated deciduous teeth on 3D silk fibroin scaffolds using static and dynamic culture paradigms.

Stem cells from human exfoliated deciduous teeth (SHED) are considered the best current source of human stem cells due to their ability to differentiate into multiple cell lineages. Dynamic co-culture systems can improve the culture environment, as they provide cells with signaling factors, extracellular matrixes, and cellular shear force, as well as enable the formation of heterotypic clusters. We seeded SHED in 3D silk fibroin porous scaffolds under static and dynamic cultures for 28 days, using the NIH3T3 cultivated medium as an induction agent. Many hepatospheres formed in these porous scaffolds, and cellular viability was shown to continually increase by MTT assays. Hepatic AFP and ALB gene expression, as well as glycogen storage, albumin secretion, and urea synthesis, were greater in cells in the 3D porous scaffold under a dynamic culture than in those cultured under 3D static culture and petri dish conditions. However, the 3D static culture is still superior to the traditional petri dish culture. The NIH3T3 cultivated medium can significantly induce hepatic differentiation of SHED, while the 3D dynamic culture system significantly enhances hepatic differentiation of SHED. This study provides alternative sources of hepatocytes for liver disease treatment.

Epidermal cells differentiated from stem cells from human exfoliated deciduous teeth and seeded onto polyvinyl alcohol/silk fibroin nanofiber dressings accelerate wound repair.

Mesenchymal stem cells (MSCs) or epidermal stem cells (ESCs) may be used as a source of cells for skin wound repair in order to preserve the patient's remaining autologous skin and reduce the wound area and pain. Many studies use MSCs as therapeutic cells for wound healing, but treatment with ESCs instead can speed up wound repair. In additional to therapeutic cells, the biomechanical properties and surface topography of the dressing also affect the speed of wound healing. Silk fibroin (SF) has the property of promoting collagen regeneration to accelerate wound healing. It has made into nanofibers as a wound healing dressing with hydrophilic polyvinyl alcohol (PVA). Methanol-treated PVA-SF dressing (PFSM) is a beadless nanofiber that can mimic the structure of endogenous extracellular matrix. In this study, SHED was first differentiated into ESCs and then effects of SHED and ESCs on wound closure were compared. Differentiation of SHED into ESCs was shown to induce growth factors that reached a maximum on the third day. In vivo, PFSM/ESC showed regeneration of granulation tissue on the third day, and the wound closure percent was 53.49%, which was 1.18-fold higher than PFSM/SHED. Therefore, the differentiation of stem cells into ESCs in advance combined with PFSM dressing can effectively accelerate wound healing in vivo. These findings can be applied to clinical treatment in the future.

CCN2 promotes drug resistance in osteosarcoma by enhancing ABCG2 expression.

In recent years, osteosarcoma survival rates have failed to improve significantly with conventional treatment modalities because of the development of chemotherapeutic resistance. The human breast cancer resistance protein/ATP binding cassette subfamily G member 2 (BCRP/ABCG2), a member of the ATP-binding cassette family, uses ATP hydrolysis to expel xenobiotics and chemotherapeutics from cells. CCN family member 2 (CCN2) is a secreted protein that modulates the biological function of cancer cells, enhanced ABCG2 protein expression and activation in this study via the α6ß1 integrin receptor and increased osteosarcoma cell viability. CCN2 treatment downregulated miR-519d expression, which promoted ABCG2 expression. In a mouse xenograft model, knockdown of CCN2 expression increased the therapeutic effect of doxorubicin, which was reversed by ABCG2 overexpression. Our data show that CCN2 increases ABCG2 expression and promotes drug resistance through the α6ß1 integrin receptor, whereas CCN2 downregulates miR-519d. CCN2 inhibition may represent a new therapeutic concept in osteosarcoma.

Senescence Induces Dysfunctions in Endothelial Progenitor Cells and Osteoblasts by Interfering Translational Machinery and Bioenergetic Homeostasis.

Age-related bone diseases are partly caused by impaired bone integrity, which are closely related to osteoblasts' activity and angiogenesis. Endothelial progenitor cells (EPCs) are the initiators of angiogenesis and found to have senescent-induced dysfunctions. The aim of this study is to investigate the effects of senescence in EPCs on osteogenesis and angiogenesis. Human primary EPCs and a murine osteoblast cell line (MC3T3-E1) are utilized in this study. The senescence of EPCs are induced by serial passages. When co-cultured with senescent EPCs, the osteoblasts demonstrate weakened alkaline phosphatase (ALP) activity and mineral deposition. On the other hand, osteoblast-induced migration decreases in senescent EPCs. As for the intracellular alterations of senescent EPCs, the activation of Akt/mTOR/p70S6K pathway, MnSOD and catalase are diminished. In contrast, the level of reactive oxygen species are significantly higher in senescent EPCs. Furthermore, senescent EPCs has decreased level intracellular ATP level and coupling efficiency for oxidative phosphorylation while the non-mitochondrial respiration and glycolysis are elevated. The senescence of EPCs impairs the functions of both osteoblasts and EPCs, suggesting EPCs' role in the pathophysiology of age-related bone diseases. Targeting the alterations found in this study could be potential treatments.

Comparing the Effects of Chitosan Scaffolds Containing Various Divalent Metal Phosphates on Osteogenic Differentiation of Stem Cells from Human Exfoliated Deciduous Teeth.

Inducing the differentiation of stem cells from human exfoliated deciduous teeth (SHEDs) proceeds with low efficiency, which greatly limits clinical applications. Divalent metal elements play an important role in osteoinductivity for bone remodeling because they can simulate bone formation and decrease bone resorption. The purpose of this study was to investigate the effect of some divalent metal phosphates on osteogenic differentiation from human exfoliated deciduous teeth. These divalent metal ions can be gradually released from the scaffold into the culture medium and continually induce osteoblastic differentiation. Experimental results revealed that SHEDs cultured in chitosan scaffolds containing divalent metal phosphates had notably increased osteoblastic differentiation compared with cells cultured without divalent metal phosphates. This effect was due to the high activity of alkaline phosphatase, as well as the bone-related gene expression of collagen type I, Runx2, osteopontin, osteocalcin, VEGF, and Ang-1, shown through RT-PCR and bone-related protein immunocytochemistry stains. A calcium-content assay further revealed significant enhancement of deposited minerals on the scaffolds after 21 days of culture, particularly for magnesium phosphate and zinc phosphate. Thus, divalent metals, except for barium phosphate, effectively promoted SHED cell differentiation and osteoblastic cell maturation. This study demonstrated that the divalent metal elements magnesium, strontium, and zinc could effectively induce SHED osteoblastic differentiation for use in tissue engineering and bone repair.

Differentiation potential of SHEDs using biomimetic periosteum containing dexamethasone.

Mimicking the architecture of the natural environment in vivo is an effective strategy for tissue engineering. The periosteum has an important function in bone regeneration. However, the harvesting of autogenous periosteum has the disadvantages of donor site morbidity and limited donor sources. This study uses an innovative artificial periosteum that forms dexamethasone (DEX)-containing polyvinyl alcohol (PVA) nanofiber obtained from skin fibrous scaffold. The aim was to evaluate the effect on bone healing of osteogenic differentiation in stems originating from human exfoliated deciduous teeth (SHEDs) in vitro. The microstructure of fabricated periosteum was observed through SEM, and results showed the apparent homogenous distribution of porous structures. DEX was also found to be continuously released into the culture medium from the periosteum for 28 days. MTT results further revealed that fabricated periosteum was cytocompatible and non-toxic to SHEDs. After 21 days of induced culture, the expression of alkaline phosphatase activity and calcium mineralization notably increased. Osteogenic results showed high early and late osteoblast gene expression by RT-PCR analysis, such as collagen type I, Runx2, OPN, and OCN. The osteoblastic protein expression of BMP-2 and OCN was clearly observed as well under fluorescence microscopy. The results, which could be applied to bone regeneration, demonstrated that skin fibrous scaffold provided an osteoinductive environment for stem cells to differentiate and that PVA nanofiber was a suitable reservoir for osteogenic factors with controlled release profile.

CCL5/CCR5 axis induces vascular endothelial growth factor-mediated tumor angiogenesis in human osteosarcoma microenvironment.

Chemokines modulate angiogenesis and metastasis that dictate cancer development in tumor microenvironment. Osteosarcoma is the most frequent bone tumor and is characterized by a high metastatic potential. Chemokine CCL5 (previously called RANTES) has been reported to facilitate tumor progression and metastasis. However, the crosstalk between chemokine CCL5 and vascular endothelial growth factor (VEGF) as well as tumor angiogenesis in human osteosarcoma microenvironment has not been well explored. In this study, we found that CCL5 increased VEGF expression and production in human osteosarcoma cells. The conditioned medium (CM) from CCL5-treated osteosarcoma cells significantly induced tube formation and migration of human endothelial progenitor cells. Pretreatment of cells with CCR5 antibody or transfection with CCR5 specific siRNA blocked CCL5-induced VEGF expression and angiogenesis. CCL5/CCR5 axis demonstrably activated protein kinase Cδ (PKCδ), c-Src and hypoxia-inducible factor-1 alpha (HIF-1α) signaling cascades to induce VEGF-dependent angiogenesis. Furthermore, knockdown of CCL5 suppressed VEGF expression and attenuated osteosarcoma CM-induced angiogenesis in vitro and in vivo. CCL5 knockdown dramatically abolished tumor growth and angiogenesis in the osteosarcoma xenograft animal model. Importantly, we demonstrated that the expression of CCL5 and VEGF were correlated with tumor stage according the immunohistochemistry analysis of human osteosarcoma tissues. Taken together, our findings provide evidence that CCL5/CCR5 axis promotes VEGF-dependent tumor angiogenesis in human osteosarcoma microenvironment through PKCδ/c-Src/HIF-1α signaling pathway. CCL5 may represent a potential therapeutic target against human osteosarcoma.

Osteogenic differentiation of stem cells from human exfoliated deciduous teeth on poly(ε-caprolactone) nanofibers containing strontium phosphate.

Mimicking the architecture of the extracellular matrix is an effective strategy for tissue engineering. Composite nanofibers similar to natural bone structure can be prepared via an electrospinning technique and used in biomedical applications. Stem cells from human exfoliated deciduous teeth (SHEDs) can differentiate into multiple cell lineages, such as cells that are alternative sources of stem cells for tissue engineering. Strontium has important functions in bone remodeling; for example, this element can simulate bone formation and decrease bone resorption. Incorporating strontium phosphate into nanofibers provides a potential material for bone tissue engineering. This study investigated the potential of poly(ε-caprolactone) (PCL) nanofibers coated or blended with strontium phosphate for the osteogenic differentiation of SHEDs. Cellular morphology and MTT assay revealed that nanofibers effectively support cellular attachment, spreading, and proliferation. Strontium-loaded PCL nanofibers exhibited higher expressions of collagen type I, alkaline phosphatase, biomineralization, and bone-related genes than pure PCL nanofibers during the osteogenic differentiation of SHEDs. This study demonstrated that strontium can be an effective inducer of osteogenesis for SHEDs. Understanding the function of bioceramics (such as strontium) is useful in designing and developing strategies for bone tissue engineering.

The correlation between lateral bowing angle of the femur and the location of atypical femur fractures.

This study is the first to report the use of data on incomplete atypical femur fracture (AFF) to evaluate the curvature of femur and explore the relationship between lateral femoral bowing angle (FBA) and AAF location. In this study, we obtained 17 cases of incomplete AFF and calculated the accurate lateral FBA and location ratio of the incomplete fracture. Incomplete fracture location was defined as a percentage (length from lesion to greater trochanter tip/entire femur length %; greater trochanter tip: 0 %; femoral condyles: 100 %). A lateral FBA of 7° was set as the point of demarcation. Eleven femurs had a lateral FBA ≤ 7° (group 1), with a median lateral FBA of 4.75° (IQR 2.5-5.9°) and a median of incomplete AFF location at 25.2 % (IQR 23.4-30.1 %). Another six femurs had a FBA > 7° (group 2) with a median of 1.8° (IQR 10.2-14.3°) and a median location at 47.7 % (IQR 38.6-54.5 %). There was a significant statistical difference in location (p < 0.05) between the two groups. The rate of BP use was 87.5 % in group 1 which was higher than 60 % in group 2. There was some degree of positive correlation between the bowing angle and location in simple linear regression (r (2) = 0.549, p < 0.001, ß = 1.789). AAFs located in diaphysis were associated with large lateral FBA. On the other hand, AAFs located in subtrochanteric region were more commonly found in femurs with smaller lateral FBA. In conclusion, the degree of the FBA was associated with AFF location.

Osteogenic differentiation and mineralization of human exfoliated deciduous teeth stem cells on modified chitosan scaffold.

Stem cells from human exfoliated deciduous teeth (SHEDs) have been considered as alternative sources of adult stem cells in tissue engineering because of their potential to differentiate into multiple cell lineages. Strontium has an important function in bone remodeling because it can simulate bone formation and decrease bone resorption. In this study, the effects of strontium phosphate on the osteogenic differentiation of SHEDs were investigated. Strontium phosphate was found to enhance the osteogenic differentiation of SHEDs with up-regulated osteoblast-related gene expression. The proliferation of SHEDs was slightly inhibited by chitosan scaffolds; however, type-I collagen expression, alkaline phosphatase activity, and calcium deposition on chitosan scaffolds containing strontium were significantly enhanced. Furthermore, cells seeded in a 3D scaffold under dynamic culture at an optimal fluid rate might enhance cellular differentiation than static culture in osteoblastic gene expression. This experiment might provide a useful cell resource and dynamic 3D culture for tissue engineering and bone repair.

Failure of the rotating-hinge knee megaprosthesis.

Recently, rotating hinge knee prostheses were applied more frequently due to improving modern implant designs. They are predominantly used in specific conditions with major bone defect or insufficiency of the collateral ligaments around the knee, often as salvage procedures. A case of rotating hinge knee megaprosthesis failure due to isolated tibial polyethylene stopper broken, which was never reported before, was investigated and treated in our institution. We suggested that rotating hinge knee prosthesis with incompetent medial collateral ligament is apt to failure due to the high valgus moment during gait. Sacrificing lateral collateral ligament or cutting the femur in slightly less than the normal 5° to 7° valgus may eliminate the risk of complication.

HO-1 overexpression attenuates endotoxin effects on CAT-2 isozymes expression.

BACKGROUND: l-arginine transport mediated by type-2 cationic amino acid transporter (CAT-2) isozymes is one crucial mechanism that regulates nitric oxide (NO) production via inducible nitric oxide synthase (iNOS). We sought to investigate the effects of heme oxygenase-1 (HO-1) overexpression on CAT-2 isozymes, e.g., CAT-2, CAT-2A, and CAT-2B. MATERIALS AND METHODS: Adult male Sprague Dawley rats were allocated to receive lipopolysaccharide (LPS), normal saline, hemin (a HO-1 inducer), tin protoporphyrin (SnPP, a HO-1 inhibitor), LPS plus hemin, or LPS plus hemin plus SnPP. After maintaining for 6 h, rats were sacrificed and the expression and activity of individual enzyme was evaluated. RESULTS: LPS increased HO activity, HO-1 concentration, NO production, l-arginine transport, and concentrations of iNOS, CAT-2, and CAT-2B in rat lungs and kidney. LPS also increased HO activity, HO-1 concentration, NO production, l-arginine transport, and iNOS concentration but decreased CAT-2 and CAT-2B concentrations in rat liver. LPS increased CAT-2A concentration in rat liver but did not affect CAT-2A concentration in rat lungs and kidney. Hemin further increased HO activity and induced HO-1 overexpression in the lungs, kidney, and liver from LPS-treated rats. In addition, the effects of LPS on NO production, l-arginine transport, and concentrations of iNOS and CAT-2 isozymes were significantly attenuated by hemin. SnPP, on the other hand, reversed the effects of hemin. CONCLUSIONS: HO-1 overexpression significantly attenuates endotoxin-induced increases in NO production and l-arginine transport. Induction of HO-1 overexpression also significantly attenuates the effects of endotoxin on the expression of iNOS and CAT-2 isozymes in septic rats.