Calcium Phosphate Carrying Simvastatin Enhances Bone Regeneration: A Systematic Review

Chitosan Nanoparticle/Simvastatin for Experimental Maxillary Bony Defect Healing: A Histological and Histomorphometrical Study

Biomaterials such as chitosan and simvastatin (Sim) have been introduced to accelerate the extensive and multicellular biological process of bone healing. The aim of this study was to evaluate the bone healing potential of chitosan and Sim, alone or combined. Forty-two male New Zealand rabbits were divided into three groups: chitosan nanoparticles (ChN), Sim and chitosan simvastatin nanoparticles (ChSimN). Two bony defects were created in the maxillary bone. The hole on the right side received one of the experimental materials, while the other side was assigned as the control and left to heal without any intervention. Bone specimens were collected at 2 and 4 weeks and then taken for histological and histomorphometrical analyses. The histological findings revealed that ChN possessed the highest number of osteoblasts and osteoclasts at weeks 2 and osteocytes after 4 weeks. There was a significant difference between the two healing periods regarding all bone parameters across all groups. ChN stood out as the only group that had a significant difference in the count of all bone cells between the two periods, thus having the best potential in promoting bone healing.

Effect of Diclofenac and Simvastatin on Bone Defect Healing-An In Vivo Animal Study

Non-steroidal, anti-inflammatory drugs and statins are two widely prescribed drug classes that affect bone formation. The aim of this study was to elucidate the effect of diclofenac and simvastatin in artificial bone defect healing. One hundred and forty-four male Wistar rats were used, and the specimens were divided into groups, with respect to the route of drug administration and the type of defect healing (with or without collagen membrane), and subgroups, with respect to the study duration (2, 4 or 8 weeks). Diclofenac was intramuscularly administered while simvastatin was administered both systemically and locally. Animals were euthanized and specimens were histomorphometrically analyzed to evaluate the percentage of new bone formation (%). Bone healing that occurred without any intervention developed more steadily than that of all other groups. Diclofenac exerted a clear, direct inhibitory effect on bone healing and its systemic administration should be avoided. The systemic administration of simvastatin was related to severe myopathy, while the solvent for the local administration of simvastatin seemed to play significant role in bone growth, as simvastatin, when it is administered intraperitoneally in a DMSO solution, appeared to promote bone healing. Local administration may have a significant impact on bone healing and it should be further investigated with the type of solvent or carrier that is used, which both may play a significant role in bone repair induction.

Amorphous calcium magnesium phosphate nanocomposites with superior osteogenic activity for bone regeneration

The seek of bioactive materials for promoting bone regeneration is a challenging and long-term task. Functionalization with inorganic metal ions or drug molecules is considered effective strategies to improve the bioactivity of various existing biomaterials. Herein, amorphous calcium magnesium phosphate (ACMP) nanoparticles and simvastatin (SIM)-loaded ACMP (ACMP/SIM) nanocomposites were developed via a simple co-precipitation strategy. The physiochemical property of ACMP/SIM was explored using transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (XRD) and high-performance liquid chromatograph (HPLC), and the role of Mg²⁺ in the formation of ACMP/SIM was revealed using X-ray absorption near-edge structure (XANES). After that, the transformation process of ACMP/SIM in simulated body fluid (SBF) was also tracked to simulate and explore the in vivo mineralization performance of materials. We find that ACMP/SIM releases ions of Ca²⁺, Mg²⁺ and PO43−, when it is immersed in SBF at 37°C, and a phase transformation occurred during which the initially amorphous ACMP turns into self-assembled hydroxyapatite (HAP). Furthermore, ACMP/SIM displays high cytocompatibility and promotes the proliferation and osteogenic differentiation of MC3T3-E1 cells. For the in vivo studies, lamellar ACMP/SIM/Collagen scaffolds with aligned pore structures were prepared and used to repair a rat defect model in calvaria. ACMP/SIM/Collagen scaffolds show a positive effect in promoting the regeneration of calvaria defect after 12 weeks. The bioactive ACMP/SIM nanocomposites are promising as bone repair materials. Considering the facile preparation process and superior in vitro/vivo bioactivity, the as-prepared ACMP/SIM would be a potential candidate for bone related biomedical applications.

Selenium-modified calcium phosphate cement can accelerate bone regeneration of osteoporotic bone defect

OBJECTIVE

The purpose is to observe whether local administration with selenium (Se) can enhance the efficacy of calcium phosphate cement (CPC) in the treatment of osteoporotic bone defects.

METHODS

Thirty ovariectomized (OVX) rats with two defects were generated and randomly allocated into the following graft study groups: (1) OVX group (n = 10), (2) CPC group (n = 10); and (3) Se-CPC group (n = 10). Then, these selenium-modified calcium phosphate cement (Se-CPC) scaffolds were implanted into the femoral epiphysis bone defect model of OVX rats for 12 weeks. Micro-CT, history, western blot and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis were used to observe the therapeutic effect and to explore the possible mechanism.

RESULT

Micro-CT and histological analysis evaluation showed that the Se-CPC group presented the strongest effect on bone regeneration and bone mineralization when compared with the CPC group and the OVX group. Protein expressions showed that the oxidative stress protein expressions, such as SOD2 and GPX1 of the Se-CPC group, are significantly higher than those of the OVX group and the CPC group, while Se-CPC remarkably reduced the expression of CAT. RT-qPCR analysis showed that the Se-CPC group displayed more OPG than the OVX and CPC groups (p < 0.05), while Se-CPC exhibited less RANKL than the OVX and CPC groups (p < 0.05).

CONCLUSION

Our current study demonstrated that Se-CPC is a scheme for rapid repair of femoral condylar defects, and these effects may be achieved by inhibiting local oxidative stress and through OPG/RANKL signaling pathway.

Hydroxyapatite-Based Magnetic Bionanocomposite as Pharmaceuticals Carriers in Chitosan Scaffolds

Hydroxyapatite (HA) is a bioceramic very similar to the mineral component of bones and teeth. It is well established that osteoblasts grow better onto HA-coated metals than on metals alone. Herein, the preparation of a new system consisting of magnetite (Fe3O4) and HA functionalized with oleic acid and simvastatin (SIMV), and incorporated in chitosan (CHI) scaffolds, was undertaken. HA was synthesized by the hydrothermal method, while Fe3O4 was synthesized by co-precipitation. The polymer matrix was obtained using a 2% CHI solution, and allowed to stir for 2 h. The final material was freeze-dried to produce scaffolds. The magnetic properties remained unchanged after the formation of the composite, as well as after the preparation of the scaffolds, maintaining the superparamagnetism. CHI scaffolds were analyzed by scanning electronic spectroscopy (SEM) and showed a high porosity, with very evident cavities, which provides the functionality of bone growth support during the remineralization process in possible regions affected by bone tissue losses. The synthesized composite showed an average particle size between 15 and 23 nm for particles (HA and Fe3O4). The scaffolds showed considerable porosity, which is important for the performance of various functions of the tissue structure. Moreover, the addition of simvastatin in the system can promote bone formation.