No abstract

No abstract

With an aging population the frequency of postmenopausal fractures is increasing. Methods to enhance the repair of osteoporotic bone repair therefore become more important to reduce the society burden of care. We asked if absorbable collagen sponges containing recombinant human bone morphogenetic protein-2 (rhBMP-2) have the potential to enhance bone repair. We randomly assigned 40 rats into the ovariectomy and sham operation groups. A segmental defect was created in the right tibia 12 weeks after ovariectomy. rhBMP-2-containing absorbable collagen sponges were implanted into the defect in half of the animals in each group. We analyzed radiographs and histological sections and performed three-point bending tests to assess repair. Radiological scores in the rhBMP-2 applied rats were higher than those in controls at the end of 8 weeks after tibial osteotomy. The specimens failed under higher loads in the rhBMP-2-applied groups and histology revealed a higher fracture healing score, including callus formation, bone union, marrow changes, and cortex remodeling. We observed no adverse tissue responses such as fibrous connective tissue formation and inflammatory cellular infiltration. rhBMP-2 in absorbable collagen sponges enhanced bone repair in segmental tibial defects of ovariectomized rats. The sponges with rhBMP-2 appeared to enhance bone repair.

No abstract

BackgroundImplant-related osteomyelitis (IRO) is recently controlled with local antibiotic delivery systems to overcome conventional therapy disadvantages. In vivo evaluation of such systems is however too little.Questions/purposesWe asked whether vancomycin (V)-containing poly-l-lactic acid/β-tricalcium phosphate (PLLA/β-TCP) composites control experimental IRO and promote bone healing in vivo.MethodsFifty-six rats were distributed to five groups in this longitudinal controlled study. Experimental IRO was established at tibiae by injecting methicillin-resistant Staphylococcus aureus (MRSA) suspensions with titanium particles in 32 rats. Vancomycin-free PLLA/β-TCP composites were implanted into the normal and infected tibiae, whereas V-PLLA/β-TCP composites and coated (C)-V-PLLA/β-TCP composites were implanted into IRO sites. Sham-operated tibiae established the control group. Radiological and histological scores were quantified with microbiological findings on weeks 1 and 6.ResultsIRO is resolved in the CV- and the V-PLLA/β-TCP groups but not in the PLLA/β-TCP group. MRSA was not isolated in the CV- and the V-PLLA/β-TCP groups at all times whereas the bacteria were present in the PLLA/β-TCP group. Radiological signs secondary to infection are improved from 10.9 ± 0.9 to 3.0 ± 0.3 in the V-PLLA/β-TCP group but remained constant in the PLLA/β-TCP group. Histology scores are improved from 24.7 ± 6.5 to 17.6 ± 4.8 and from 27.6 ± 7.9 to 32.4 ± 8.9 in the CV-PLLA/β-TCP and the V-PLLA/β-TCP groups, respectively. New bone was formed in all the PLLA/β-TCP group at weeks 1 and 6.ConclusionsCV- and V-PLLA/β-TCP composites controlled experimental IRO and promoted bone healing.Clinical relevanceCV- and V-PLLA/β-TCP composites have the potential of controlling experimental IRO and promoting bone healing.

Abstract:In this study, a novel antibiotic carrier system for use in the treatment of implant-related and chronic osteomyelitis was developed. Sulbactam-cefoperazone was introduced to rods of polyhydroxybutyrate-co-hydroxyvalerate (22 mol % HV, w/w), a member of a family of microbialorigin polymer that is biodegradable, biocompatible, and osteoconductive due to its piezoelectric property. The antibiotic-loaded carrier was implanted into the infection site that was induced by Staphylococcus aureus inoculation into the rabbit tibia. The effectiveness of this was assessed macroscopically, radiographically, bacteriologically, and histopathologically. Findings of infection subsided on day 15 and almost complete remission was observed on day 30. The control side that contained antibiotic-free rods, however, worsened. These findings prompted us to conclude that the novel biodegradable antibiotic carrier developed in the present study seems to be a promising candidate for use in the treatment of severe bone infection.

Background Vaccines that incorporate multiple SARS‐CoV‐2 antigens can further broaden the breadth of virus‐specific cellular and humoral immunity. This study describes the development and immunogenicity of SARS‐CoV‐2 VLP vaccine that incorporates the four structural proteins of SARS‐CoV‐2. Methods VLPs were generated in transiently transfected HEK293 cells, purified by multimodal chromatography, and characterized by tunable‐resistive pulse sensing, AFM, SEM, and TEM. Immunoblotting studies verified the protein identities of VLPs. Cellular and humoral immune responses of immunized animals demonstrated the immune potency of the formulated VLP vaccine. Results Transiently transfected HEK293 cells reproducibly generated vesicular VLPs that were similar in size to and expressing all four structural proteins of SARS‐CoV‐2. Alum adsorbed, K3‐CpG ODN‐adjuvanted VLPs elicited high titer anti‐S, anti‐RBD, anti‐N IgG, triggered multifunctional Th1‐biased T‐cell responses, reduced virus load, and prevented lung pathology upon live virus challenge in vaccinated animals. Conclusion These data suggest that VLPs expressing all four structural protein antigens of SARS‐CoV‐2 are immunogenic and can protect animals from developing COVID‐19 infection following vaccination.

No abstract