Jiacan Su

Biocompatibility and osteogenicity of degradable Ca-deficient hydroxyapatite scaffolds from calcium phosphate cement for bone tissue engineering

Ca-deficient hydroxyapatite (CDHA) porous scaffolds were successfully fabricated from calcium phosphate cement (CPC) by a particle-leaching method. The morphology, porosity and mechanical strength as well as degradation of the scaffolds were characterized. The results showed that the CDHA scaffolds with a porosity of 81% showed open macropores with pore sizes of 400-500mum. Thirty-six per cent of these CDHA scaffolds were degraded after 12 weeks in Tris-HCl solution. Mesenchymal stem cells (MSCs) were cultured, expanded and seeded on the scaffolds, and the proliferation and differentiation of MSCs into osteoblastic phenotype were determined using MTT assay, alkaline phosphatase activity and scanning electron microscopy. The results revealed that the CDHA scaffolds were biocompatible and had no negative effects on the MSCs in vitro. The in vivo biocompatibility and osteogenicity of the scaffolds were investigated. Both CDHA scaffolds and MSC/scaffold constructs were implanted in rabbit mandibles and studied histologically. The results showed that CDHA scaffolds exhibited good biocompatibility and osteoconductivity. Moreover, the introduction of MSCs into the scaffolds dramatically enhanced the efficiency of new bone formation, especially at the initial stage after implantation (from 2 to 4 weeks). However, the CDHA scaffolds showed as good biocompatibility and osteogenicity as the hybrid ones at 8 weeks. These results indicate that the CDHA scaffolds fulfill the basic requirements of bone tissue engineering scaffold.

Injectable bioactive calcium-magnesium phosphate cement for bone regeneration.

Novel injectable and degradable calcium-magnesium phosphate cement (CMPC) with rapid-setting characteristic was developed by the introduction of magnesium phosphate cement (MPC) into calcium phosphate cement (CPC). The calcium-magnesium phosphate cement prepared under the optimum P/L ratio exhibited good injectability and desired workability. It could set within 10 min at 37 degrees C in 100% relative humidity and the compressive strength could reach 47 MPa after setting for 48 h, indicating that the prepared cement has relatively high initial mechanical strength. The results of in vitro degradation experiments demonstrated the good degradability of the injectable CMPC, and its degradation rate occurred significantly faster than that of pure CPC in simulated body fluid (SBF) solution. It can be concluded that the novel injectable calcium-magnesium phosphate cement is highly promising for a wide variety of clinical applications, especially for the development of minimally invasive techniques.

In vitro degradability, bioactivity and cell responses to mesoporous magnesium silicate for the induction of bone regeneration

Mesoporous magnesium silicate (m-MS) was synthesized, and the in vitro degradability, bioactivity and primary cell responses to m-MS were investigated. The results suggested that the m-MS with mesoporous channels of approximately 5nm possessed the high specific surface area of 451.0m(2)/g and a large specific pore volume of 0.41cm(3)/g compared with magnesium silicate (MS) without mesopores of 75m(2)/g and 0.21cm(3)/g, respectively. The m-MS was able to absorb a large number of water, with water absorption of 74% compared with 26% for MS. The m-MS was also degradable in a Tris-HCl solution, with a weight loss ratio of 40wt% after a 70-day immersion period. The m-MS exhibited good in vitro bioactivity, inducing apatite formation on its surfaces after soaking in simulated body fluid (SBF) at a faster rate than observed for MS. The m-MS surface clearly promoted the proliferation and differentiation of MC3T3-E1 cells, and their normal cell morphology indicated excellent cytocompatibility. This study suggested that mesoporous magnesium silicate with a high specific surface area and pore volume had suitable degradability and good bioactivity and biocompatibility, making it an excellent candidate biomaterial for the induction of bone regeneration.

Composite scaffolds of mesoporous bioactive glass and polyamide for bone repair

A bone-implanted porous scaffold of mesoporous bioglass/polyamide composite (m-BPC) was fabricated, and its biological properties were investigated. The results indicate that the m-BPC scaffold contained open and interconnected macropores ranging 400–500 μm, and exhibited a porosity of 76%. The attachment ratio of MG-63 cells on m-BPC was higher than polyamide scaffolds at 4 hours, and the cells with normal phenotype extended well when cultured with m-BPC and polyamide scaffolds. When the m-BPC scaffolds were implanted into bone defects of rabbit thighbone, histological evaluation confirmed that the m-BPC scaffolds exhibited excellent biocompatibility and osteoconductivity, and more effective osteogenesis than the polyamide scaffolds in vivo. The results indicate that the m-BPC scaffolds improved the efficiency of new bone regeneration and, thus, have clinical potential for bone repair.

Bioactive and degradable scaffolds of the mesoporous bioglass and poly(L-lactide) composite for bone tissue regeneration

Bioactive scaffolds of the mesoporous bioglass (m-BG) and poly(l-lactide) (PLLA) composite were fabricated using a solvent casting-particulate leaching method. The results showed that incorporation of the m-BG into PLLA significantly improved the in vitro water absorption, degradability and apatite-formation ability of the m-BG-PLLA composite scaffolds, which were m-BG content dependent. Moreover, addition of the m-BG into PLLA could neutralize the acidic degradation products of PLLA and thus compensate for the decrease of the pH value. In cell culture experiments, the results revealed that the m-BG-PLLA composite scaffolds enhanced attachment, proliferation and alkaline phosphatase (ALP) activity of MC3T3-E1 cells, which were m-BG content dependent. In animal experiments, the SRmCT and histological elevation results showed that the composite scaffolds significantly improved osteogenesis in vivo. It can be suggested that incorporation of bioactive materials of m-BG into PLLA was a useful approach to obtain composite scaffolds with improved properties (such as water absorption, degradability, bioactivity and osteogenesis), and the composite scaffolds with excellent biocompatibility could be promising bioactive implants for bone regeneration.

In vitro degradability, bioactivity and primary cell responses to bone cements containing mesoporous magnesium–calcium silicate and calcium sulfate for bone regeneration

Mesoporous calcium sulfate-based bone cements (m-CSBC) were prepared by introducing mesoporous magnesium–calcium silicate (m-MCS) with specific surface area (410.9 m² g−1) and pore volume (0.8 cm³ g−1) into calcium sulfate hemihydrate (CSH). The setting time of the m-CSBC was longer with the increase of m-MCS content while compressive strength decreased. The degradation ratio of m-CSBC increased from 48.6 w% to 63.5 w% with an increase of m-MCS content after soaking in Tris–HCl solution for 84 days. Moreover, the m-CSBC containing m-MCS showed the ability to neutralize the acidic degradation products of calcium sulfate and prevent the pH from dropping. The apatite could be induced on m-CSBC surfaces after soaking in SBF for 7 days, indicating good bioactivity. The effects of the m-CSBC on vitamin D3 sustained release behaviours were investigated. It was found that the cumulative release ratio of vitamin D3 from the m-CSBC significantly increased with the increase of m-MCS content after soaking in PBS (pH = 7.4) for 25 days. The m-CSBC markedly improved the cell-positive responses, including the attachment, proliferation and differentiation of MC3T3-E1 cells, suggesting good cytocompatibility. Briefly, m-CSBC with good bioactivity, degradability and cytocompatibility might be an excellent biocement for bone regeneration.

Surgical Treatment of Calcaneal Fractures of Sanders Type II and III by a Minimally Invasive Technique Using a Locking Plate

The aim of the present study was to investigate the outcomes of surgical treatment of calcaneal fractures of Sanders type II and III using a minimally invasive technique and a locking plate. We reviewed 33 feet in 33 consecutive patients with Sanders type II and III calcaneal fractures who had undergone a minimally invasive technique using percutaneous reduction and locking plates. All operations were performed by the same surgeons. The postoperative evaluation included radiographs, determination of restoration of Böhlers angle and Gissanes angle, and administration of the American Orthopaedic Foot and Ankle Society ankle-hind foot scale, Maryland Foot Score, and visual analog scale of pain. The mean visual analog scale score was 1.6 ± 1.4 when radiographic fracture healing was observed. The median functional score of the 33 patients (33 feet) reached 82 (interquartile range 80 to 99) at the last follow-up evaluation according to the American Orthopaedic Foot and Ankle Society ankle-hind foot scale and 89 (interquartile range 80 to 99) according to Maryland Foot Score. All cases achieved restoration of a normal Böhlers angle and Gissanes angle. Postoperative superficial infections occurred in 2 patients, subtalar arthritis developed in 2, and no soft tissue necrosis was observed. For Sanders type II and III fractures of the calcaneus bone, treatment with a minimally invasive technique combining percutaneous reduction and locking plate fixation provided satisfactory clinical results, with a lower incidence of complications. However, longer term studies with a larger sample size and more randomized controlled trials are required to define the superiority of our minimally invasive technique compared with conventional surgical treatment of calcaneal fractures.

Nanocalcium-deficient hydroxyapatite–poly (ε-caprolactone)–polyethylene glycol–poly (ε-caprolactone) composite scaffolds

A bioactive composite of nano calcium-deficient apatite (n-CDAP) with an atom molar ratio of calcium to phosphate (Ca/P) of 1.50 and poly(ɛ-caprolactone)–poly(ethylene glycol)–poly(ɛ-caprolactone) (PCL–PEG–PCL) was synthesized, and a composite scaffold was fabricated. The composite scaffolds with 40 wt% n-CDAP contained well interconnected macropores around 400 μm, and exhibited a porosity of 75%. The weight-loss ratio of the n-CDAP/PCL–PEG–PCL was significantly greater than nano hydroxyapatite (n-HA, Ca/P = 1.67)/PCL–PEG–PCL composite scaffolds during soaking into phosphate-buffered saline (pH 7.4) for 70 days, indicating that n-CDAP-based composite had good degradability compared with n-HA. The viability ratio of MG-63 cells was significantly higher on n-CDAP than n-HA-based composite scaffolds at 3 and 5 days. In addition, the alkaline phosphatase activity of the MG-63 cells cultured on n-CDAP was higher than n-HA-based composite scaffolds at 7 days. Histological evaluation showed that the introduction of n-CDAP into PCL–PEG–PCL enhanced the efficiency of new bone formation when the composite scaffolds were implanted into rabbit bone defects. The results suggested that the n-CDAP-based composite exhibits good biocompatibility, biodegradation, and osteogenesis in vivo.

Matrine prevents bone loss in ovariectomized mice by inhibiting RANKL-induced osteoclastogenesis

Osteoporosis is a metabolic bone disease characterized by decreased bone density and strength due to excessive loss of bone protein and mineral content. The imbalance between osteogenesis by osteoblasts and osteoclastogenesis by osteoclasts contributes to the pathogenesis of postmenopausal osteoporosis. Estrogen withdrawal leads to increased levels of proinflammatory cytokines. Overactivated osteoclasts by inflammation play a vital role in the imbalance. Matrine is an alkaloid found in plants from the Sophora genus with various pharmacological effects, including anti‐inflammatory activity. Here we demonstrate that matrine significantly prevented ovariectomy‐induced bone loss and inhibited osteoclastogenesis in vivo with decreased serum levels of TRAcp5b, TNF‐α, and IL‐6. In vitro matrine significantly inhibited osteoclast differentiation induced by receptor activator for NF‐κB ligand (RANKL) and M‐CSF in bone marrow monocytes and RAW264.7 cells as demonstrated by tartrate‐resistant acid phosphatase (TRAP) staining and actin‐ring formation as well as bone resorption through pit formation assays. For molecular mechanisms, matrine abrogated RANKL‐induced activation of NF‐κB, AKT, and MAPK pathways and suppressed osteoclastogenesis‐related marker expression, including matrix metalloproteinase 9, NFATc1, TRAP, C‐Src, and cathepsin K. Our study demonstrates that matrine inhibits osteoclastogenesis through modulation of multiple pathways and that matrine is a promising agent in the treatment of osteoclast‐related diseases such as osteoporosis.—Chen, X., Zhi, X., Pan, P., Cui, J., Cao, L., Weng, W., Zhou, Q., Wang, L., Zhai, X. Zhao, Q., Hu, H., Huang, B., Su, J. Matrine prevents bone loss in ovariectomized mice by inhibiting RANKL‐induced osteoclastogenesis. FASEB J. 31, 4855–4865 (2017). www.fasebj.org

Inhalation of water electrolysis-derived hydrogen ameliorates cerebral ischemia-reperfusion injury in rats - A possible new hydrogen resource for clinical use.

Hydrogen is a kind of noble gas with the character to selectively neutralize reactive oxygen species. Former researches proved that low-concentration of hydrogen can be used to ameliorating cerebral ischemia/reperfusion injury. Hydrogen electrolyzed from water has a hydrogen concentration of 66.7%, which is much higher than that used in previous studies. And water electrolysis is a potential new hydrogen resource for regular clinical use. This study was designed and carried out for the determination of safety and neuroprotective effects of water electrolysis-derived hydrogen. Sprague-Dawley rats were used as experimental animals, and middle cerebral artery occlusion was used to make cerebral ischemia/reperfusion model. Pathologically, tissues from rats in hydrogen inhalation group showed no significant difference compared with the control group in HE staining pictures. The blood biochemical findings matched the HE staining result. TTC, Nissl, and TUNEL staining showed the significant improvement of infarction volume, neuron morphology, and neuron apoptosis in rat with hydrogen treatment. Biochemically, hydrogen inhalation decreased brain caspase-3, 3-nitrotyrosine and 8-hydroxy-2-deoxyguanosine-positive cells and inflammation factors concentration. Water electrolysis-derived hydrogen inhalation had neuroprotective effects on cerebral ischemia/reperfusion injury in rats with the effect of suppressing oxidative stress and inflammation, and it is a possible new hydrogen resource to electrolyze water at the bedside clinically.