THE USE OF ENDOTHELIAL PROGENITOR CELLS (EPCS) AND LOCAL ANTIBIOTICS FOR THE TREATMENT OF INFECTED NONUNIONS IN A SMALL ANIMAL MODEL
Bibliographic record
Abstract
The purpose of this study was to assess the efficacy of Endothelial Progenitor Cell-based therapy (EPC) in the presence and absence of local antibiotics (ABX) in the treatment of infected nonunions in a small animal model. We hypothesized that EPC therapy would promote bone healing and eradicate infection, and that the addition of local antibiotics would further facilitate these outcomes. A 5-mm segmental defect was created and stabilized with mini-plate fixation in the right femur of Fischer 344 rats. A control solution (Experiment 1: non-contaminated arm) or an inoculum of Staphylococcus epidermidis (Experiment 2: contaminated arm) was delivered at the defect site on a gelatin scaffold. Fourteen days later, a second surgery was performed and one of the following treatments was applied in both the non-contaminated and contaminated arms, creating a total of seven groups: 1) control (no treatment), 2) EPC, 3) EPC + ABX (local vancomycin and rifampin), and 4) ABX (only in the contaminated arm). Biweekly radiographs were obtained to monitor bone healing and infection. All animals were euthanized 10 weeks after the second surgery. Soft tissue and fixation material samples were collected and processed for microbiological analysis. The radiographs were scored and assessed blindly for union status, defect filling, and infection. Bone healing was also assessed with micro-CT and biomechanics following specimen harvest. Our primary outcome for Experiment 2 was the rate of non-infected union. Experiment 1: Non-contaminated: All animals in the EPC and EPC+ABX groups demonstrated significantly improved healing relative to controls with regards to union rates. Similarly radiographic scores, micro-CT (bone volume (BV) and bone volume fraction (BV/TV)), and biomechanics (torque and stiffness) all demonstrated significantly improved outcomes in the EPC and EPC+ABX compared to the control group. There were no significant differences between the EPC and EPC+ABX groups (Table 1). Experiment 2: Contaminated: Animals that received EPC+ABX or ABX alone demonstrated high rates of infection eradication compared to the EPC only and control groups (Table 2). The EPC groups (EPC only and EPC+ABX) demonstrated improved bone healing outcomes relative to control and ABX alone groups. A post-hoc analysis test comparing rates of non-infected union showed that the EPC+ABX group had a significantly higher rate of non-infected union compared to ABX alone and control group (p=0.003). These results demonstrate several important findings. First, the use of local ABX (vancomycin and rifampin) alone or in combination with EPCs is highly effective at eradicating infection in a small animal model of infected nonunion. Second, combining local ABX with EPCs does not negatively impact the fracture-healing efficacy of EPCs. Finally, the combined treatment of infected nonunions with EPCs and local ABX significantly improved both infection and healing rates. These results support the continued investigation of EPCs and local ABX as a potential single-stage treatment for infected nonunions. For any figures or tables, please contact the authors directly.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".