Ex Vivo Gene Therapy for Hemophilia A That Enhances Safe Delivery and Sustained In Vivo Factor VIII Expression from Lentivirally Engineered Endothelial Progenitors
Why this work is in the frame
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Bibliographic record
Abstract
Novel therapeutic strategies for hemophilia must be at least as effective as current treatments and demonstrate long-term safety. To date, several small clinical trials of hemophilia gene transfer have failed to show the promise of preclinical evaluations. Therefore, we wanted to develop and evaluate the feasibility of a novel ex vivo gene transfer strategy whereby cells derived from progenitor cells are engineered to express factor VIII (FVIII) and then implanted subcutaneously to act as a depot for FVIII expression. Circulating blood outgrowth endothelial cells (BOECs) were isolated from canine and murine blood and transduced with a lentiviral vector encoding the canine FVIII transgene. To enhance safety, these cells were implanted subcutaneously in a Matrigel scaffold, and the efficacy of this strategy was compared with i.v. delivery of engineered BOECs in nonhemophilic nonobese diabetic/severe combined immunodeficiency mice. Therapeutic levels of FVIII persisted for 15 weeks, and these levels of stable expression were extended to 20 weeks when the cytomegalovirus promoter was replaced with the thrombomodulin regulatory element. Subsequent studies in immunocompetent hemophilic mice, pretreated with tolerizing doses of FVIII or with transient immunosuppression, showed therapeutic FVIII expression for 27 weeks before the eventual return to baseline levels. This loss of transgene expression appears to be due to the disappearance of the implanted cells. The animals treated with either of the two tolerizing regimens did not develop anti-FVIII antibodies. Biodistribution analysis demonstrated that BOECs were retained inside the subcutaneous implants. These results indicate, for the first time, that genetically modified endothelial progenitor cells implanted in a subcutaneous scaffold can provide sustained therapeutic levels of FVIII and are a promising and safe treatment modality for hemophilia A. Disclosure of potential conflicts of interest is found at the end of this article.
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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 it