Magnetic PLGA microspheres loaded with SPIONs promoted the reconstruction of bone defects through regulating the bone mesenchymal stem cells under an external magnetic field.

Superparamagnetic iron oxide nanoparticles (SPIONs) have been presented to regulate the migration and osteogenic differentiation of bone mesenchymal stem cells (BMSCs) under magnetic field (MF). However, the toxicity and short residence for the massively exposed SPIONs at bone defects compromises their practical application. Herein, SPIONs were encapsulated into PLGA microspheres to overcome these shortcomings. Three types of PLGA microspheres (PFe-I, PFe-II and PFe-III) were prepared by adjusting the feeding amount of SPIONs, in which the practical SPIONs loading amounts was 1.83%, 1.38% and 1.16%, respectively. The average diameter of the fabricated microspheres ranged from 160 µm to 200 µm, having the porous and rough surfaces displayed by SEM. Moreover, they displayed the magnetic property with a saturation magnetization of 0.16 emu/g. In vitro cell studies showed that most of BMSCs were adhered on the surface of PFe-II microspheres after 2 days of co-culture. Moreover, the osteoblasts differentiation of BMSCs was significantly promoted by PFe-II microspheres after 2 weeks of co-culture, as shown by detecting osteogenesis-related proteins expressions of ALP, COLI, OPN and OCN. Afterward, PFe-II microspheres were surgically implanted into the defect zone of rat femoral bone, followed by exposure to an external MF, to evaluate their bone repairing effect in vivo. At 6th week after treatment with PFe-II + MF, the bone mineral density (BMD, 263.97 ± 25.99 mg/cm3), trabecular thickness (TB.TH, 0.58 ± 0.08 mm), and bone tissue volume/total tissue volume (BV/TV, 78.28 ± 5.01%) at the defect zone were markedly higher than that of the PFe-II microspheres alone (BMD, 194.34 ± 26.71 mg/cm3; TB.TH, 0.41 ± 0.07 mm; BV/TV, 50.49 ± 6.41%). Moreover, the higher expressions of ALP, COLI, OPN and OCN in PFe-II + MF group were displayed in the repairing bone. Collectively, magnetic PLGA microspheres together with MF may be a promising strategy for repairing bone defects.

HA/MgO nanocrystal-based hybrid hydrogel with high mechanical strength and osteoinductive potential for bone reconstruction in diabetic rats.

Bone repair and regeneration processes are markedly impaired in diabetes mellitus (DM). Intervening approaches similar to those developed for normal healing conditions have been adopted to combat DM-associated bone regeneration. However, limited outcomes were achieved for these approaches. Hence, together with osteoconductive hydroxyapatite (HA) nanocrystals, osteoinductive magnesium oxide (MgO) nanocrystals were uniformly mounted into the network matrix of an organic hydrogel composed of cysteine-modified γ-polyglutamic acid (PGA-Cys) to construct a hybrid and rough hydrogel scaffold. It was hypothesized that the HA/MgO nanocrystal hybrid hydrogel (HA/MgO-H) scaffold can significantly promote bone repair in DM rats via the controlled release of Mg2+. The HA/MgO-H scaffold exhibited a sponge-like morphology with porous 3D networks inside it and displayed higher mechanical strength than a PGA-Cys scaffold. Meanwhile, the HA/MgO-H scaffold gradually formed a tough hydrogel with G' of more than 1000 Pa after hydration, and its high hydration swelling ratio was still retained. Moreover, after the chemical degradation of the dispersed MgO nanocrystals, slow release of Mg2+ from the hydrogel matrix was achieved for up to 8 weeks because of the chelation between Mg2+ and the carboxyl groups of PGA-Cys. In vitro cell studies showed that the HA/MgO-H scaffold could not only effectively promote the migration and proliferation of BMSCs but could also induce osteogenic differentiation. Moreover, in the 8th week after implanting the HA/MgO-H scaffold into femur bone defect zones of DM rats, more effective bone repair was presented by micro-CT imaging. The bone mineral density (397.22 ± 16.36 mg cm-3), trabecular thickness (0.48 ± 0.07 mm), and bone tissue volume/total tissue volume (79.37 ± 7.96%) in the HA/MgO-H group were significantly higher than those in the other groups. Moreover, higher expression of COL-I and OCN after treatment with HA/MgO-H was also displayed. The bone repair mechanism of the HA/MgO-H scaffold was highly associated with reduced infiltration of pro-inflammatory macrophages (CD80+) and higher angiogenesis (CD31+). Collectively, the HA/MgO-H scaffold without the usage of bioactive factors may be a promising biomaterial to accelerate bone defect healing under diabetes mellitus.

Bone-Inspired Tube Filling Decellularized Matrix of Toad Cartilage Provided an Osteoinductive Microenvironment for Mesenchymal Stem Cells to Facilitate the Radius Defect Repair of Rabbit.

Toad bone not only contains the rich cartilage-like matrix but also presents low immunogenicity. It is inferred that decellularized toad bone matrix (dBECM) may provide the more profitable osteoinductive microenvironment for mesenchymal stem cells (MSCs) to promote the repair of bone defects. Herein, a hollow bone-inspired tube is first made from hydroxyapatite (HA) and poly (γ-glutamic acid) (PGA), and then MSCs/dBECM hydrogel is uniformly filled to its central cavity, constructing a biomimetic bone (dBECM + MSCs - PGA + HA). In vitro scratch and transwell experiments show that dBECM hydrogel not only effectively promotes migration and proliferation of MSCs but also induces their osteogenic differentiation. Moreover, the less inflammatory macrophages infiltrate at rat skin after subcutaneously injecting dBECM hydrogel, indicating its low potential for inflammatory attack. After implanting dBECM + MSCs - PGA + HA to critical radius defect of rabbit, X-ray and CT imaging shows that the cortex is effectively regenerated and the medullary cavity recanalization is completed at 20 weeks. Moreover, the expression of Collagen-II and OCN are obviously increased in the defect after implanting dBECM + MSCs - PGA + HA. The therapeutic mechanism of dBECM + MSCs - PGA + HA scaffold are highly associated with the enhanced angiogenesis. Collectively, the biomimetic dBECM + MSCs - PGA + HA scaffold may be a promising strategy to improve radius defect healing efficiency.

Design, synthesis and antitumor activity of a novel PEG-A6-conjugated irinotecan derivative.

A novel PEG-A6-conjugated irinotecan derivative 8 was designed and synthesized as antitumor agent by the PEGylation and A6-peptide modification of irinotecan. In vivo antitumor activity screening assay revealed that 8 exhibited better in vivo antiproliferation activity than irinotecan and its previous PEG-cRGD-conjugated derivative BGC0222 in MIA PaCa-2, NCI-H446, MDA-MB-231, HT-29 and NCI-N87 xenograft models, while the tumor of one in six mice in NCI-H446 assay and the tumors of two in six mice in MIA PaCa-2 assay completely subsided and disappeared within the 21-day period of 8-treatment, indicating that 8 should be a potential antitumor agent.

Cross-linked nanoparticles of silk fibroin with proanthocyanidins as a promising vehicle of indocyanine green for photo-thermal therapy of glioma.

Instability of silk fibroin nanoparticles (SFNPs) in physiologic condition hinders its application as drug delivery vehicle. Herein, indocyanine green (ICG) loaded silk fibroin nanoparticles (ICG-SFNPs) was firstly prepared and then crosslinked by proanthocyanidins to obtain the stable ICG-CSFNPs for killing the residual tumour niche under near infra-red irradiation (NIR) after surgery. The particle size and zeta potentials of ICG-CSFNPs was 120.1 nm and -40.4 mV, respectively. Moreover, ICG-CSFNPs exhibited good stability of particle size in the physiological medium. Meanwhile, the stable photothermal properties of ICG-CSFNPs were not compromised even after several cycles of NIR. Few of the ICG-CSFNPs were phagocytized by RAW264.7 macrophage in vitro, while they were easily internalized by C6 glioma cells, resulting in their significant toxicity on tumour cells after NIR. The pharmacokinetic study showed that ICG-CSFNPs had a longer blood circulation time than ICG-SFNPs, making them more distribution in glioma after intravenous administration in vivo. Meanwhile, the pharmacological study showed the more effective inhibition of tumour growth was exhibited by ICG-CSFNPs in C6 glioma-bearing mice after NIR. Overall, the cross-linked nanoparticles of silk fibroin may be a promising vehicle of ICG for photothermal therapy of glioma after surgical resection.

Design, synthesis and pharmacological evaluation of a novel PEG-cRGD-conjugated irinotecan derivative as potential antitumor agent.

A novel PEG-cRGD-conjugated irinotecan derivative BGC0222 was designed and synthesized as antitumor agent. Antitumor activity screening assay indicated that BGC0222 exhibited better in vitro antiproliferation activity than irinotecan and NKTR-102 against HT29, MIA PaCa-2 and MCF-7 tumor cell lines, with IC50 of 1.83 ±â€¯0.09 µM, 3.95 ±â€¯0.16 µM and 0.68 ±â€¯0.04 µM, respectively, while it displayed better in vivo antiproliferation activity than irinotecan and NKTR-102 in HT-29, MIA PaCa-2, NCI-H446, U-87 MG and MDA-MB-231 xenograft models. The action mechanism of BGC0222 was then investigated by integrin-binding competition (IBC) and chick chorioallantoic membrane (CAM) angiogenesis assays, which indicated that BGC0222 may exert antitumor activity by binding to αvß3 target and consequently inducing neovascularization effect. Pharmacokinetic analysis showed that BGC0222 could slowly and steadily release irinotecan, which was subsequently metabolized into 7-ethyl-10-hydroxycamptothecin (SN-38) in the whole blood.

Homing of ICG-loaded liposome inlaid with tumor cellular membrane to the homologous xenografts glioma eradicates the primary focus and prevents lung metastases through phototherapy.

Currently, phototherapy initiated by local irradiation with a near-infrared (NIR) laser has emerged as a promising strategy for cancer treatment owing to its low toxicity. However, a key problem for effective phototherapy is how to specifically deliver a sufficient dose of photosensitizers to a tumor focus. Herein, indocyanine green (ICG), a United States Food and Drug Administration (US FDA)-approved photosensitizer, was first encapsulated in an inner aqueous compartment of liposome (ICG-LIP) to improve its stability. Thereafter, tumor cell membranes were isolated from native glioma cells and subsequently inlaid in the bilayer lipid membrane of ICG-LIP to construct cell-like liposomes (ICG-MCLs). ICG was easily encapsulated into the ICG-MCLs with a very high encapsulation efficiency, reaching 78.01 ± 0.72% and its concentration in the final formulation reached 200 µg mL-1. The ICG-MCLs displayed a spherical morphology with a hydrodynamic diameter (Dh) of 115.0 ± 0.5 nm, a PDI of 0.14, and a zeta potential of -11.2 ± 0.9 mV. Moreover, ICG-MCLs exhibited a good stability in terms of particle size and significantly improved the chemical stability of ICG in pH 7.4 PBS at 37 °C. In addition, the temperature of the ICG-MCLs rapidly increased to 63 °C after 10 min irradiation and this was maintained for a longer time. Owing to the cancer cell membrane associated protein, the ICG-MCLs were specifically internalized by homogenous glioma C6 cells in vitro, which resulted in the strong red fluorescence of ICG in cytoplasm. Moreover, in vivo imaging showed that the ICG-MCLs were effectively homed to the tumor site of C6 glioma-bearing Xenograft nude mice through vein injection, which resulted in the temperature of the tumor site rapidly rising, allowing the killing of tumor cells after local NIR irradiation. After treatment with the ICG-MCLs, the primary tumor focus was completely eradicated and lung metastases were effectively inhibited. In conclusion, liposomes inlaid with tumor cellular membranes may serve as an excellent nanoplatform for homologous-targeting phototherapy using ICG.

pH-sensitive polymeric nanoparticles of mPEG-PLGA-PGlu with hybrid core for simultaneous encapsulation of curcumin and doxorubicin to kill the heterogeneous tumour cells in breast cancer.

Most breast tumours are heterogeneous and not only contain the bulk of differentiated tumour cells but also a small population of highly tumorigenic and intrinsically drug-resistant cancer stem cells (CSCs). Herein, a pH-sensitive nanoparticle with simultaneous encapsulation of curcumin and doxorubicin (CURDOX-NPs) was prepared by using monomethoxy (polyethylene glycol)-b-P (D,L-lactic-co-glycolic acid)-b-P (L-glutamic acid) polymer to simultaneously target the differentiated tumor cells and CSCs. CURDOX-NPs had a mean diameter of 107.5 nm and zeta potential of -13.7 mV, determined by DLS. Drug-loading efficiency for curcumin and doxorubicin was reaching to 80.30% and 96.2%, respectively. Moreover, a cascade sustained-release profiles with the faster release of CUR followed by a slower release of DOX was observed in normal pH7.4 condition. Moreover, a pH-sensitive release profile for each cargo was seen in pH5.0 condition. The anti-tumour effect of CURDOX-NPs on CSCs-enriching MCF-7/ADR mammospheres was confirmed by in vitro. Moreover, a significant regression of tumour growth after treatment with CURDOX-NPs was also observed in Xenograft mice model. The percentage of CSCs in tumour significantly decreased from 39.9% in control group to 6.82% after treatment with CURDOX-NPs. The combinational delivery of CUR and DOX may a potentially useful therapeutic strategy for refractory breast cancer.

Skin-penetrating polymeric nanoparticles incorporated in silk fibroin hydrogel for topical delivery of curcumin to improve its therapeutic effect on psoriasis mouse model.

A poor percutaneous penetration capability for most topical anti-inflammatory drugs is one of the main causes compromising their therapeutic effects on psoriatic skin. Even though curcumin has shown a remarkable efficacy in the treatment of psoriasis, its effective penetration through the stratum corneum is still a major challenge during transdermal delivery. The aim of our study was to design skin-permeating nanoparticles (NPs) to facilitate delivery of curcumin to the deeper layers of the skin. A novel amphiphilic polymer, RRR-α-tocopheryl succinate-grafted-ε-polylysine conjugate (VES-g-ε-PLL) was synthesized and self-assembled into polymeric nanoparticles. The nanoparticles of VES-g-ε-PLL exhibiting an ultra-small hydrodynamic diameter (24.4nm) and a positive Zeta potential (19.6mV) provided a strong skin-penetrating ability in vivo. Moreover, curcumin could effectively be encapsulated in the polymeric nanoparticles with a drug loading capacity of 3.49% and an encapsulating efficiency of 78.45%. In order to prolong the retention time of the ultra-small curcumin-loaded nanoparticles (CUR-NPs) in the skin, silk fibroin was used as a hydrogel-based matrix to further facilitate topical delivery of the model drug. In vitro studies showed that CUR-NPs incorporated in silk fibroin hydrogel (CUR-NPs-gel) exhibited a slower release profile of curcumin than the plain CUR-gel, without compromising the skin penetration ability of CUR-NPs. In vivo studies on miquimod-induced psoriatic mice showed that CUR-NPs-gel exhibited a higher therapeutic effect than CUR-NPs as the former demonstrated a more powerful skin-permeating capability and a more effective anti-keratinization process. CUR-NPs-gel was therefore able to inhibit the expression of inflammatory cytokines (TNF-α, NF-κB and IL-6) to a greater extent. In conclusion, the permeable nanoparticle-gel system may be a potential carrier for the topical delivery of lipophilic anti-psoriatic drugs.

[Otimization of auxiliary lines for proximal femoral intramedullary nail in the treatment of simple femoral intertrochanteric fractures].

OBJECTIVE: To investigate the clinical outcomes of C-arm X-ray fluoroscopy before incision to make assistant lines and insert the guide wire of PFNA and PFNA blade. METHODS: From January 1st 2012 to January 1st 2015, 132 intertrochanteric fracture patients of type 31A1 and 31A2 according to AO-classification, were retrospectively analyzed. Among them, 62 patients(14 males and 48 females) aged from 52 to 95 years with a mean age of(69.58±8.55) years in traditional group were operated by traditional procedure, while 70 patients in the skin marking group included 15 males and 55 females aged from 61 to 88 years with a mean age of(71.94±7.64) years, on the basis of the traditional operation method, the assistant line of the body surface and the C-arm X-ray was increased, and the guide pin positioning of the proximal femoral nail and the spiral blade was guided by the auxiliary line in the operation. Operative time, frequency of C-arm fluoroscopy, Harris hip score of the third months after surgery and the complications in both groups were queried for statistical analysis. RESULTS: In addition to skin making group 1 patients had superficial wound infection complications, all patients were stage I wound healing. All patients were followed up for 3 to 18 months with an average of (6.81±3.07) months. The operative time was significantly reduced in skin marking group (56.16±6.36) minutes compared to traditional group (59.06±9.19) minutes (P>=0.035). And the frequency of C-arm fluoroscopy of skin marking group was(25.89±5.81) times which was also significantly reduced compared to traditional group(31.32±9.81) times (P<0.001). There was no statistical difference in Harris hip score at 3 months after operation and the complication rate between the two groups(P>0.05). CONCLUSIONS: In this study, a simple and easy method of assistant line marking can shorten the operation time and reduce the number of times of operation.

[Case-control study on modified femoral prosthesis in reducing the incidence of patellar clunk syndrome after the initial posterior stabilized total knee arthroplasty].

OBJECTIVE: To explore therapeutic effects of modified femoral prosthesis applied in the initial posterior stabilized total knee arthroplasty. METHODS: From April 1, 2012 to January 1, 2013, 156 patients with knee osteoarthritis underwent posterior stabilized total knee arthroplasty by the same director of orthopedic surgeon. Sixty-one patients were treated with modified femoral prosthesis, including 7 males and 54 females, with an average age of (68.34 +/- 5.41) years old; and 95 patients were treated with conventional designed femoral prosthesis, including 14 males and 81 females, with an average age of (69.92 +/- 5.11) years old. Indexes including age, body mass index, Insall-Salvati index, type of prosthesis, occurrence rate of patella click syndrome, postoperative line of force of lower extremity and postoperative function of the knee joint were observed and recorded. And American Knee Society (AKS) score was used to evaluate the clinical results. RESULTS: All the patients were followed up, and the duration ranged from 36 to 56 weeks, with a mean of 45.31 weeks. Among patients in the conventional designed femoral prosthesis group, 7 patients had patella click syndrome, but there was no patient having patellar click syndrome in the modified femoral prosthesis group. Postoperative knee activity of patients in the modified femoral prosthesis group was (110.98 +/- 10.32) degrees, which was better than (107.05 +/- 8.61) degrees in the conventional designed femoral prosthesis group. The AKS score in the modified femoral prosthesis group was 129.79 +/- 9.63 during 21 to 28 days after operation, which was higher than 126.85 +/- 7.79 in the conventional designed femoral prosthesis group. CONCLUSION: New designed femoral components are effective to reduce the occurrence rate of postoperative patellar click syndrome and obtain better early functional recovery from knee surgery.

[Analysis of clinical effects of uncovertebral joints resection and decompression for the treatment of cervical spondylotic radiculopathy through anterior approach].

OBJECTIVE: To analyze the clinical and radiologic outcomes of bilateral uncovertebral joints resection and decompression in treating cervical spondylotic radiculopathy through anterior approach. METHODS: From January 2007 to December 2009, the clinical data of 56 patients with cervical spondylotic radiculopathy undergoing sugical treatment were retrospectively analyzed. There were 33 males and 23 females with an average age of (58.83 +/- 8.01) years (ranged 41 to 72). The course was from 5 to 48 months with an average of (14.09 +/- 8.54) months. All patients underwent bilateral uncovertebral joints resection, vertebral canal decompression and fusion through anterior approach. Perioperative, radiologic,nerve functional parameters were analyzed before and after operation. Perioperative parameters included hospital stay days and blood loss volume and operative time; radiologic parameters included vertebral height and lordosis angle and fusion rate; and according to JOA score to evaluate the nerve function. RESULTS: All patients were followed up from 12 to 30 months with an average of 18.2 months. Hospital stay days, blood loss volume and operative time were (4.42 +/- 0.25) d, (195.51 +/- 23.67) ml and (145.52 +/- 28.29) min, respectively. Preoperative vertebral height was (5.19 +/- 0.03) cm, and postoperative 1 year arrived to (5.37 +/- 0.29) cm, there was no significant difference between preoperative and postoperative (P > 0.05). Lordosis angle increased from preoperative (1.53 +/- 0.03) degrees to (7.78 +/- 0.66) degrees at the 1 year after operation (P<0.01). Fusion rate was 96.5% at the 1 year after operation. JOA score increased from preoperative 8.69 +/- 2.13 to 15.58 +/- 2.45 at the 1 year after operation (P < 0.001). According to standard of JOA scoring, 20 cases were excellent, 28 good, 7 fair and 1 poor. CONCLUSION: Uncovertebral joints resection and decompression through anterior cervical approach in treating cervical spondylotic radiculopathy is safe and reliable, which can get satisfactory clinical outcomes. This surgical procedure is suitabl oe for the patients of cervical spondylosis, especially combined canal stenosis and osteophytosis of the uncovertebral joint.

Novel three-dimensional nerve tissue engineering scaffolds and its biocompatibility with Schwann cells.

OBJECTIVE: To develop a novel scaffolding method for the copolymers poly lactide-co-glycolide acid (PLGA) to construct a three-dimensional (3-D) scaffold and explore its biocompatibility through culturing Schwann cells (SCs) on it. METHODS: The 3-D scaffolds were made by means of melt spinning, extension and weaving. The queueing discipline of the micro-channels were observed under a scanning electronic microscope (SEM).The sizes of the micropores and the factors of porosity were also measured. Sciatic nerves were harvested from 3-day-old Sprague Dawley (SD) rats for culture of SCs. SCs were separated, purified, and then implanted on PLGA scaffolds, gelatin sponge and poly-L-lysine (PLL)-coated tissue culture polystyrene (TCPS) were used as biomaterial and cell-supportive controls, respectively. The effect of PLGA on the adherence, proliferation and apoptosis of SCs were examined in vitro in comparison with gelatin sponge and TCPS. RESULTS: The micro-channels arrayed in parallel manners, and the pore sizes of the channels were uniform. No significant difference was found in the activity of Schwann cells cultured on PLGA and those on TCPS (P larger than 0.05), and the DNA of PLGA scaffolds was not damaged. CONCLUSION: The 3-D scaffolds developed in this study have excellent structure and biocompatibility, which may be taken as a novel scaffold candidate for nerve-tissue engineering.

The treatment for multilevel noncontiguous spinal fractures.

We report the outcome of 30 patients with multilevel noncontiguous spinal fractures treated between 2000 and 2005. Ten cases were treated conservatively (group A), eight cases were operated on at only one level (group B), and 12 cases were treated surgically at both levels (group C). All cases were followed up for 14-60 months (mean 32 months). Initial mobilisation with a wheelchair or crutches in group A was 9.2 +/- 1.1 weeks, which was significantly longer than groups B and C with 6.8+/-0.7 weeks and 3.1 +/- 0.4 weeks, respectively. Operative time and blood loss in group C were significantly more than group B. The neurological deficit improved in six cases in group A (60%), six in group B (75%) and eight in group C (80%). Correction of kyphotic deformity was significantly superior in groups C and B at the operated level, and increasing deformity occurred in groups A and B at the non-operated level. From the results we believe that three treatment strategies were suitable for multilevel noncontiguous spinal fractures, and individualised treatment should be used in these patients. In the patients treated surgically, the clinical and radiographic outcomes are much better.