Shock wave assisted intracellular delivery of antibiotics against bone infection with Staphylococcus aureus via P2X7 receptors.

Background: Treatment of chronic osteomyelitis (bone infection) remains a clinical challenge; in particular, it requires enhanced delivery of antibiotic drugs for the treatment of intracellular Staphylococcus aureus (S. aureus), which prevents infection recurrence and resistance. Previous studies have found that noninvasive shock waves used to treat musculoskeletal diseases can alter cell permeability, however, it is unclear whether shock waves alter cell membrane permeability in chronic osteomyelitis. Furthermore, it remains unknown whether such changes in permeability promote the entry of antibiotics into osteoblasts to exert antibacterial effects. Methods: In our study, trypan blue staining was used to determine the shock wave parameters that had no obvious damage to the osteoblast model; the effect of shocks waves on the cell membrane permeability of osteoblast model was detected by BODIPY®FL vancomycin; high performance liquid chromatography-mass spectrometry (HLPC-MS) was used to detect the effect of shock wave on the entry of antibiotics into the osteoblast model; plate colony counting method was used to detect the clearance effect of shock wave assisted antibiotics on S. aureus in the osteoblast model. To explore the mechanism, the effect of different pulses of shock waves on S. aureus was examined by plate colony counting method, besides, P2X7 receptor in osteoblast was detected by immunofluorescence and the extracellular ATP levels was detected. Furthermore, the effect of P2X7 receptor antagonists KN-62 or A740003 on the intracellular antibacterial activity of shock-assisted antibiotics was observed. Then, we used S. aureus to establish a rat model of chronic tibial osteomyelitis and investigated the efficacy and safety of shock-wave assisted antibiotics in the treatment of chronic osteomyelitis in rats. Results: The viability of the osteoblast models of intracellular S. aureus infection was not significantly affected by the application of up to 400 shock wave pulses at 0.21 mJ/mm2. Surprisingly, the delivery of BODIPY®FL vancomycin to osteoblast model cells was markedly enhanced by this shock wave treatment. Furthermore, the shock wave therapy increased the delivery of hydrophilic antibiotics (vancomycin and cefuroxime sodium), but not lipophilic antibiotics (rifampicin and levofloxacin), which improved the intracellular antibacterial effect. Afterwards, we discovered that shock wave treatment increased the extracellular concentration of ATP (the P2X7 receptor activator)， while KN-62 or A740003, a P2X7 receptor inhibitor, decreased intracellular antibacterial activity. We then found that 0.1 mL of 1 × 1011 CFU/mL ATCC25923 S. aureus was suitable for modeling chronic osteomyelitis in rats. Besides, the shock wave-assisted vancomycin treatment with the strongest antibacterial and osteogenic effects among the tested treatments was confirmed in vivo by imaging examination, microbiological cultures, and histopathology, with favorable safety. Conclusions: Our results suggest that shock waves can promote the entry of antibiotics into osteoblasts for antibacteria by changing the cell membrane permeability in a P2X7 receptor-dependent manner. Besides, considering antibacterial and osteogenic efficiency and a high degree of safety in rat osteomyelitis model, shock wave-assisted vancomycin treatment may thus represent a possible adjuvant therapy for chronic osteomyelitis.

Risk of osteoporosis in patients treated with direct oral anticoagulants vs. warfarin: an analysis of observational studies.

Aims: Evidence on the association between the risk of new-onset osteoporosis and oral anticoagulants remains controversial. We aimed to compare the risk of osteoporosis associated with the use of direct oral anticoagulants (DOACs) with that associated with warfarin use. Methods: Studies published up to 15 March 2023 that investigated the association between the use of DOACs and warfarin and the incidence of osteoporosis were identified by online searches in PubMed, Embase, the Cochrane Library, and Web of Science conducted by two independent investigators. Random-effects or fixed-effect models were employed to synthesize hazard ratios (HRs)/relative ratios (RRs) with 95% confidence intervals (CIs) for estimating the risk of osteoporosis correlated with DOAC and warfarin prescriptions (PROSPERO No. CRD42023401199). Results: Our meta-analysis ultimately included four studies involving 74,338 patients. The results suggested that DOAC use was associated with a significantly lower incidence of new-onset osteoporosis than warfarin use (pooled HR: 0.71, 95% CI: 0.57 to 0.88, p < 0.001, I 2: 85.1%). Subanalyses revealed that rivaroxaban was associated with a lower risk of osteoporosis than both warfarin and dabigatran. In addition, DOACs were associated with a lower risk of developing osteoporosis than warfarin in both male and female patients, in patients with atrial fibrillation (AF), and in patients who underwent therapy for > 365 days. Conclusion: DOAC users experienced a lower incidence of osteoporosis than warfarin users. This study may give us insight into safe anticoagulation strategies for patients who are at high risk of developing osteoporosis. Systematic review registration: https://www.crd.york.ac.uk/PROSPERO, identifier CRD42023401199.

Effects of Bisphosphonates Treatments in Osteopenic Older Women: A Systematic Review and Meta-Analysis.

Aims: To review the effects of bisphosphonates on bone density, fractures, and bone markers in osteopenic older women. Methods: Relevant articles published before February 2022 were searched in PubMed, EMBASE, and the Cochrane Library. All randomized controlled trials that reported incident fractures, bone mineral density (BMD), bone markers, or adverse events with bisphosphonates in osteopenic older women were included. The quality of included studies was assessed using the Cochrane Risk of Bias tool. The risk ratios (RRs) for fractures, net percent change in bone mineral density and differences in bone markers were calculated using a meta-analysis. Results: A total of 11 studies were included in our meta-analysis. Bisphosphonates significantly increased the percent changes in the lumbar spine BMD (WMD, 5.60; 95% CI, 4.16-7.03; I 2 = 93.6%), hip BMD (WMD, 4.80; 95% CI, 2.93 to 6.66; I 2 = 97.1%), total body BMD (WMD, 3.24; 95% CI, 2.12-4.35; I 2 = 90.9%), femoral neck BMD (WMD, 4.02; 95% CI, 1.70-6.35; I 2 = 91.8%) and trochanter BMD (WMD, 5.22; 95% CI, 3.51-6.93; I 2 = 83.6%) when compared to placebo. Zoledronate was associated with a great treatment effect on fragility fracture (RR, 0.63; 95% CI, 0.50-0.79), clinical vertebral fracture (RR, 0.41; 95% CI, 0.22-0.76), and radiographic vertebral fracture (RR, 0.60; 95% CI, 0.27-1.35) compared to placebo. Meanwhile, alendronate was also associated with beneficial effects on fragility fracture (RR, 0.40; 95% CI, 0.15-1.07), clinical vertebral fracture (RR, 0.46; 95% CI, 0.17-1.24), and radiographic vertebral fracture (RR, 0.64; 95% CI, 0.38-1.09). In addition, the use of bisphosphonates reduced the concentration of procollagen type I N-terminal propeptide (PINP) and C-terminal telopeptide of type I collagen (CTX) over placebo by 15.79 (95% CI, -18.92 to -12.66; I 2 = 28.4%), -0.23 (95% CI, -0.35 to -0.10; I 2 = 91.3%), respectively. Although there was insufficient evidence to determine their safety, these bisphosphonates may have an effect on cancer, cardiac events, and mortality in osteopenic older women. Conclusion: All bisphosphonates examined were associated with beneficial effects on fractures, BMD, and bone markers in women with osteopenia. Further randomized controlled trials are necessary to clarify the safety of bisphosphonates in women with osteopenia.