Intermittent PTH(1–84) is osteoanabolic but not osteoangiogenic and relocates bone marrow blood vessels closer to bone-forming sites
Bibliographic record
Abstract
Intermittent parathyroid hormone (PTH) is anabolic for bone. Our aims were to determine (1) whether PTH stimulates bone angiogenesis and (2) whether vascular endothelial growth factor (VEGF A) mediates PTH-induced bone accrual. Male Wistar rats were given PTH(1-84) daily, and trabecular bone mass increased 150% and 92% after 30 and 15 days, respectively. The vascular system was contrasted to image and quantify bone vessels with synchrotron radiation microtomography and histology. Surprisingly, bone vessel number was reduced by approximately 25% and approximately 40% on days 30 and 15, respectively. PTH redistributed the smaller vessels closer to bone-formation sites. VEGF A mRNA expression in bone was increased 2 and 6 hours after a single dose of PTH and returned to baseline by 24 hours. Moreover, anti-VEGF antibody administration (1) blunted the PTH-induced increase in bone mass and remodeling parameters, (2) prevented the relocation of bone vessels closer to bone-forming sites, and (3) inhibited the PTH-induced increase in mRNA of neuropilin 1 and 2, two VEGF coreceptors associated with vascular development and function. In conclusion, PTH(1-84) is osteoanabolic through VEGF-related mechanism(s). Further, PTH spatially relocates blood vessels closer to sites of new bone formation, which may provide a microenvironment favorable for growth.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 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 | 0.001 |
| 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".