Effects of intra-articular D-amino acids combined with systemic vancomycin on an experimental Staphylococcus aureus-induced periprosthetic joint infection.

BACKGROUND: The D-isoforms of amino acids (D-AAs) exhibit anti-biofilm potential against a diverse range of bacterial species in vitro, while its role in vivo remains unclear. The aim of this study was to investigate the effects of a combination of D-AAs and vancomycin on a PJI rat model. METHODS: Eight-week-old male SD rats were randomized to the control group, sham group, vancomycin group, D-AAs-vancomycin group. After treatment for 6 weeks, we analysed the levels of inflammatory factors in serum, behavioural change, imaging manifestations. The anti-biofilm ability of D-AAs was detected by crystal violet staining and scanning electron microscope observation, and its ability to assist antibiotics in killing bacteria was assessed by culture of bacteria. Additionally, micro-CT and histological analysis were used to evaluate the impact of D-AAs combined with vancomycin on the bone remodelling around the prosthesis. RESULTS: The group treated with a D-AAs-vancomycin combination sustained normal weight gain and exhibited reduced the serum levels of α2M, IL-1ß, IL-6, IL-10, TNF-α and PGE2. Moreover, treated with D-AAs in combination with vancomycin improved the weight-bearing activity performance, increased the sizes and widths of distal femurs, and improved Rissing scale scoring. In particular, treatment using D-AAs enhanced the ability of vancomycin to eradicate Staphylococcus aureus, as demonstrated by the dispersion of existing biofilms and the inhibition of biofilm formation that occurred in a concentration-dependent manner. This treatment combination also resulted in a reduction in bacterial burden with in the soft tissues, bones, and implants. Furthermore, D-AAs-vancomycin combination treatment attenuated abnormal bone remodelling around the implant, as evidenced by an observed increase in BMD, BV/TV, and Tb.Th and the presence of reduced Trap+ osteoclasts and elevated osterix+ osteo-progenitors. CONCLUSIONS: Combining D-AAs with vancomycin provides an effective therapeutic strategy for the treatment of PJI by promoting biofilm dispersion to enhance antimicrobial activity.

Artesunate alleviates interleukin­1ß­induced inflammatory response and apoptosis by inhibiting the NF­κB signaling pathway in chondrocyte­like ATDC5 cells, and delays the progression of osteoarthritis in a mouse model.

Osteoarthritis (OA) is a progressive and degenerative joint disorder that is highly prevalent worldwide and for which there is currently no effective medical therapy. Artesunate (ART), a natural compound used to treat malaria, possesses diverse biological properties, including the regulation of inflammation and apoptosis in various cells; however, its role in OA remains unclear. The aim of the present study was to investigate the effects of ART on interleukin (IL)­1ß­induced chondrocyte­like ATDC5 cells and in an OA mouse model. The results revealed that ART dose­dependently relieved the inhibitory effect of IL­1ß on cell viability. Moreover, ART significantly reduced the overexpression of matrix metalloproteinase (MMP)­3, MMP­13, a disintegrin and metalloproteinase with thrombospondin motifs­5 and cyclooxygenase­2 at both the gene and protein levels in chondrocyte­like ATDC5 cells stimulated by IL­1ß. Furthermore, ART decreased the expression of pro­apoptotic Bax, cleaved caspase­3 and cleaved caspase­7 in a dose­dependent manner, and increased the expression of the anti­apoptotic factor Bcl­2. These changes were mediated by the inhibitory effect of ART on the nuclear factor­κB signaling pathway, defined as repression of the phosphorylation of IκBα and p65, and improved redistribution of p65. Additionally, ART blocked the advancement of the calcified cartilage zone and the loss of proteoglycan, and lowered histological scoring of OA in a mouse model. Taken together, these results indicate that ART may be of value as a therapeutic agent for OA.

Artesunate, an Anti-Malaria Agent, Attenuates Experimental Osteoarthritis by Inhibiting Bone Resorption and CD31hiEmcnhi Vessel Formation in Subchondral Bone.

Osteoarthritis (OA) is a common and debilitating joint disease worldwide without interventions available to reverse its progression. Artesunate (ART), an anti-malaria agent, possesses diverse biological activities, including the inhibition of osteoclastogenesis and angiogenesis in various cells, but its role in subchondral bone during OA progression is not known. Here, we explored the curative effects of ART on the pathogenesis of OA in anterior cruciate ligament transection (ACLT) mice models. We found that ART attenuated articular cartilage degeneration, defined by lowered histologic scoring of OA and retarded calcification of the cartilage zone. Moreover, ART improved the expression of lubricin and aggrecan and reduced the expression of collagen X (Col X) and matrix metalloproteinase-13 (MMP-13). In parallel, ART normalized abnormal subchondral bone remodeling by maintaining bone volume fraction (BV/TV) and subchondral bone plate thickness (SBP Th) and reducing trabecular pattern factor (Tb.pf) compared to the vehicle-treated mice. Our results indicated that ART suppressed osteoclastic bone resorption through regulating RANKL-OPG system, restored coupled bone remodeling by indirectly inhibiting TGF-ß/Smad2/3 signaling. Additionally, ART abrogated CD31hiEmcnhi vessel formation via downregulating the expression of vascular endothelial growth factor (VEGF) and angiogenin-1 in subchondral bone. In conclusion, ART attenuates ACLT-induced OA by blocking bone resorption and CD31hiEmcnhi vessel formation in subchondral bone, indicating that this may be a new therapeutic alternative for OA.

Halofuginone Attenuates Osteoarthritis by Rescuing Bone Remodeling in Subchondral Bone Through Oral Gavage.

Osteoarthritis (OA) is a common debilitating joint disorder worldwide without effective medical therapy. Articular cartilage and subchondral bone act in concert as a functional unit with the onset of OA. Halofuginone is an analog of the alkaloid febrifugine extracted from the plant Dichroa febrifuga, which has been demonstrated to exert inhibition of SMAD 2/3 phosphorylation downstream of the TGF-ß signaling pathway and osteoclastogenesis. To investigate whether halofuginone (HF) alleviates OA after administration by oral gavage, 3-month-old male mice were allocated to the Sham group, vehicle-treated anterior cruciate ligament transection (ACLT) group, and HF-treated ACLT group. The immunostaining analysis indicated that HF reduced the number of matrix metalloproteinase 13 (MMP-13) and collagen X (Col X) positive cells in the articular cartilage. Moreover, HF lowered histologic OA score and prevented articular cartilage degeneration. The micro-computed tomography (µCT) scan showed that HF maintained the subchondral bone microarchitecture, demonstrated by the restoration of bone volume fraction (BV/TV), subchondral bone plate thickness (SBP.Th.), and trabecular pattern factor (Tb.Pf) to a level comparable to that of the Sham group. Immunostaining for CD31 and µCT based angiography showed that the number and volume of vessels in subchondral bone was restored by HF. HF administered by oral gavage recoupled bone remodeling and inhibited aberrant angiogenesis in the subchondral bone, further slowed the progression of OA. Therefore, HF administered by oral gavage could be a potential therapy for OA.

Isoliquiritigenin blunts osteoarthritis by inhibition of bone resorption and angiogenesis in subchondral bone.

Isoliquiritigenin (ISL), a natural flavonoid extracted from licorice, has been demonstrated to exert attenuation of osteoclastogenesis and anti-angiogenesis activity in a wide variety of cells. Here, we first evaluated the effects of ISL on pathogenesis of osteoarthritis in a mouse model of OA. The data showed that ISL blunted progression of OA and lowered the Osteoarthritis Research Society International (OARSI)-Modified Making Score and protected the articular cartilage. The thickness of calcified cartilage zone was significantly decreased in ISL-treated ACLT mice compared with vehicle group. ISL increased expression level of lubricin and decreased collagen X (Col X), matrix metalloproteinase-13 (MMP-13). Moreover, ISL reduced aberrant active subchondral bone remodelling, including lowered trabecular pattern factor (Tb.pf) and increased bone volume/tissue volume (BV/TV, %) and thickness of subchondral bone plate (SBP) compared with vehicle-treated group. The results of immunostaining further revealed that ISL directly reduced RANKL-RANK-TRAF6 singling pathway induced osteoclastogenesis, prevented abnormal bone formation through indirect inhibition of TGF-ß release. Additionally, ISL exerts anti-angiogenesis effects in subchondral bone through direct suppression of MMP-2. These results indicated that ISL attenuates progression of OA by inhibition of bone resorption and angiogenesis in subchondral bone, indicating that this may be a potential preventive therapy for OA.

Isoliquiritigenin suppresses IL-1ß induced apoptosis and inflammation in chondrocyte-like ATDC5 cells by inhibiting NF-κB and exerts chondroprotective effects on a mouse model of anterior cruciate ligament transection.

Isoliquiritigenin (ISL), a natural flavonoid extracted from licorice, has been demonstrated to exert attenuation of the nuclear factor-κB (NF-κB) signaling pathway and anti-inflammatory activity in a wide variety of cells. In the present study, the authors first evaluated the effects of ISL on cartilage degeneration in interleukin-1ß (IL-1ß)-stimulated chondrocyte-like ATDC5 cells and in a mouse model of osteoarthritis (OA). The data of a cell counting kit-8 and flow cytometry assay indicated that ISL suppressed the inhibitory effect of IL-1ß on cell viability. The mRNA and protein expression levels of cyclooxygenase-2 and matrix metalloproteinase-13 were significantly decreased, while the expression of collagen II was increased, as indicated by RT-qPCR and western blot analysis following the chondrocyte-like ATDC5 cells were co-intervened with IL-1ß and ISL for 48 h. Also, ISL attenuated protein expressions level of pro-apoptotic Bax, cleaved-caspase-3 and cleaved-caspase-9 and promoted expression of anti-apoptotic Bcl-2. Moreover, ISL inhibited NF-κB p65 phosphorylation induced by IL-1ß. In addition, ISL also increased improved the thickness of hyaline cartilage and the production of proteoglycans in the cartilage matrix in a mouse OA model. These results indicated that ISL exerted anti-inflammatory and anti-apoptotic effects on IL-1ß-stimulated chondrocyte-like ATDC5 cells, which may be associated with the downregulation of the NF-κB signaling pathway. In this way, the data supported the conclusion that ISL may be a novel potential preventive agent suitable for use in OA therapy.

Halofuginone attenuates articular cartilage degeneration by inhibition of elevated TGF­ß1 signaling in articular cartilage in a rodent osteoarthritis model.

Osteoarthritis (OA) is the most common degenerative condition of the weight­bearing joints worldwide without effective medical therapy. In order to investigate whether administration of halofuginone (HF) may attenuate OA, the present study allocated 3­month­old male mice into Sham group, vehicle­treated anterior cruciate ligament transection (ACLT) group and HF­treated ACLT group. The present study determined that HF treatment reduced the expression of matrix metallopeptidase­13 and collagen X in articular cartilage. Additionally, it lowered the Osteoarthritis Research Society International­Modified Mankin score and prevented the loss of articular cartilage from Safranin O and Fast Green staining. HF reduced the progression of osteoarthritis by downregulating abnormally elevated TGF­ß1 activity in articular cartilage. Administration of HF may be a potential preventive therapy for OA.

Treatment of the femoral shaft nonunion with double plate fixation and bone grafting: A case series of 14 patients.

INTRODUCTION: The management of femoral shaft nonunion still remains a challenge in orthopaedic surgery. It represents a serious postoperative problem for the patient, associated with plate breakage and loosening, bone defect, shortening deformity and infection. A double plate fixation combined with bone grafting may become a promising therapeutic strategy for the treatment of patients with femoral shaft nonunion. In this study, our goal was to evaluate the clinical outcome of a novel approach for 14 consecutive patients with femoral shaft nonunion using double plate fixation with bone grafting. METHODS: Retrospective data from June 2010 to August 2012 were obtained from records for 14 consecutive femoral shaft aseptic nonunion patients treated with double plate fixation combined with bone grafting. Nine patients were men and five patients were woman and average age of the patients was 26 years (range from 22 to 32 years). The mean time since injury was 26.2 months. The nonunion had resulted from repeated internal fixation failure (including plate or intramedullary nail fixation) in nine cases and primary internal fixation in five cases. RESULTS: All the 14 patients were followed up for an average of 14.8 (10-25) months. All cases achieved bony union without wound infection or fixation failure and the mean time to union was 5.2 months (range 4-7 months). CONCLUSION: Double plate fixation and bone grafting are a promising method for femoral shaft nonunion. In addition, this strategy is useful for such a nonunion caused by a repeated plate or intramedullary nail fixation failure with bone defect due to its strong stability with three-dimensional fixation and fully bone graft availability.