FP460VASCULAR CALCIFICATION, BUT NOT KIDNEY DYSFUNCTION, IN EXPERIMENTAL CKD LEADS TO SIGNIFICANT ALTERATION TO PHOSPHATE CIRCADIAN VARIATION
Bibliographic record
Abstract
INTRODUCTION: Despite being integral to homeostasis, the circadian rhythms of calcium, phosphate, and their hormonal regulators (PTH, FGF-23) are not well characterized. Chronic kidney disease (CKD) disrupts mineral homeostasis and causes pathologies like vascular calcification (VC). This study sought to examine the effects of CKD and VC on mineral/hormonal circadian rhythm. METHODS: High-adenine diet (0.25%) was used to induce CKD in adult male Sprague-Dawley rats (n=13). After 5weeks animals were switched to control diet (0.5%-phosphate) for 1week, then switched to high-phosphate (1.0%-phosphate) for 1week. A parallel control group (n=7) was fed 0.5% phosphate for 6weeks then switched to high-phosphate for 1week. 3days later, animals were anesthetized, infused with radiolabeled phosphate, had blood samples collected over 30minutes, and were euthanized. Prior to CKD induction, all animals had 24hour assessment with blood sampling every 3hours. Similar assessments were conducted after 1week 0.5%-phosphate diet and 1week 1.0%-phosphate diet. RESULTS: Distinct circadian patterning was observed in phosphate (p<0.0001), FGF-23 and PTH (p<0.05) at baseline; calcium did not show circadian variation. CKD did not alter the patterns observed at baseline. 1week of 1.0%phosphate diet in CKD led to loss of circadian rhythmicity in phosphate and FGF-23; as well as VC in 62% of CKD animals. CKD and VC led to a predisposition for radiolabeled phosphate to influx into vasculature and bone, where in controls it influxes into kidneys. Adjusting for VC, CKD rats without VC displayed phosphate circadian variation (p<0.01) whereas CKD rats with VC did not. CONCLUSIONS: To our knowledge this is the first experimental examination of circadian variation in CKD. This study found (i) CKD does not impact circadian variation in phosphate, PTH, or FGF23, (ii) that VC in CKD removes phosphate circadian rhythmicity, and (iii) that hyperphosphatemia in CKD removes FGF-23 circadian rhythm.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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 source (direct Gemma or distilled Codex), 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".