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Bone & Joint Research
Vol. 11, Issue 5 | Pages 260 - 269
3 May 2022
Intermittent parathyroid hormone increases stability and improves osseointegration of initially unstable implants
Staats K Sosa BR Kuyl E Niu Y Suhardi V Turajane K Windhager R Greenblatt MB Ivashkiv L Bostrom MPG Yang X
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Aims

To develop an early implant instability murine model and explore the use of intermittent parathyroid hormone (iPTH) treatment for initially unstable implants.

Methods

3D-printed titanium implants were inserted into an oversized drill-hole in the tibiae of C57Bl/6 mice (n = 54). After implantation, the mice were randomly divided into three treatment groups (phosphate buffered saline (PBS)-control, iPTH, and delayed iPTH). Radiological analysis, micro-CT (µCT), and biomechanical pull-out testing were performed to assess implant loosening, bone formation, and osseointegration. Peri-implant tissue formation and cellular composition were evaluated by histology.

The Bone & Joint Journal
Vol. 103-B, Issue 7 Supple B | Pages 135 - 144
1 Jul 2021
Inhibition of PAD4 mediated neutrophil extracellular traps prevents fibrotic osseointegration failure in a tibial implant murine model
Kuyl E Shu F Sosa BR Lopez JD Qin D Pannellini T Ivashkiv LB Greenblatt MB Bostrom MPG Yang X
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Aims

Aseptic loosening is a leading cause of uncemented arthroplasty failure, often accompanied by fibrotic tissue at the bone-implant interface. A biological target, neutrophil extracellular traps (NETs), was investigated as a crucial connection between the innate immune system’s response to injury, fibrotic tissue development, and proper bone healing. Prevalence of NETs in peri-implant fibrotic tissue from aseptic loosening patients was assessed. A murine model of osseointegration failure was used to test the hypothesis that inhibition (through Pad4-/- mice that display defects in peptidyl arginine deiminase 4 (PAD4), an essential protein required for NETs) or resolution (via DNase 1 treatment, an enzyme that degrades the cytotoxic DNA matrix) of NETs can prevent osseointegration failure and formation of peri-implant fibrotic tissue.

Methods

Patient peri-implant fibrotic tissue was analyzed for NETs biomarkers. To enhance osseointegration in loose implant conditions, an innate immune system pathway (NETs) was either inhibited (Pad4-/- mice) or resolved with a pharmacological agent (DNase 1) in a murine model of osseointegration failure.

The Bone & Joint Journal
Vol. 102-B, Issue 7 Supple B | Pages 3 - 10
1 Jul 2020
2020 John Charnley Award: The antimicrobial potential of bacteriophage-derived lysin in a murine debridement, antibiotics, and implant retention model of prosthetic joint infection
Sosa BR Niu Y Turajane K Staats K Suhardi V Carli A Fischetti V Bostrom M Yang X
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Aims

Current treatments of prosthetic joint infection (PJI) are minimally effective against Staphylococcus aureus biofilm. A murine PJI model of debridement, antibiotics, and implant retention (DAIR) was used to test the hypothesis that PlySs2, a bacteriophage-derived lysin, can target S. aureus biofilm and address the unique challenges presented in this periprosthetic environment.

Methods

The ability of PlySs2 and vancomycin to kill biofilm and colony-forming units (CFUs) on orthopaedic implants were compared using in vitro models. An in vivo murine PJI model of DAIR was used to assess the efficacy of a combination of PlySs2 and vancomycin on periprosthetic bacterial load.