Abstract 13838: Smooth Muscle Cells Are the Origin of the Majority of Foam Cells in Atherosclerotic Lesions of Apolipoprotein E-deficient Mice
Bibliographic record
Abstract
Background: Apolipoprotein E-deficient (ApoE -/- ) mice are the most frequently used model of human atherosclerosis. Foam cells in mouse lesions have been believed to be primarily macrophage-derived using traditional staining with macrophage markers. Recent studies indicated that smooth muscle cells (SMCs) comprise at least 50% of foam cells in human coronary atherosclerosis, and express reduced levels of ATP-binding cassette transporter A1 (ABCA1) when compared to intimal leucocytes. Identification of SMC-derived foam cells is challenging due to the absence of classic SMC markers and expression of macrophage markers by a high percentage of intimal SMCs in mouse and human lesions. Hypothesis: Unlike human atherosclerosis, foam cells in ApoE -/- mice are primarily macrophage- rather than SMC-derived. Methods: 8-week-old male and female ApoE -/- mice were fed a Western diet for 6 weeks to promote lesion development. Flow cytometry was used to estimate the proportion of leukocyte- and SMC-derived foam cells in cell suspensions from digested ascending aortas. Foam cells were identified by the neutral lipid dye BODIPY, and leukocyte-derived were distinguished from SMC-derived foam cells by expression of CD45 (a pan-leukocyte marker), and I-A/I-E (antigen presenting cell markers), which have not been reported to be expressed by SMCs. SMC origin was confirmed using a SMC-specific epigenetic lineage marker. ABCA1 level was also measured in the two foam cell populations. Results: 69.47±3.20 % (male) and 73.33±2.35 % (female) (mean ± SEM, n=9 each) of foam cells in ApoE -/- mouse lesions were CD45 and I-A/I-E negative, and were confirmed by SMC lineage marker to be predominantly SMC-derived. SMC-derived foam cells were thus significantly greater than leukocyte-derived foam cells in ApoE -/- mice ( P <0.01), and exhibited three times lower ABCA1 protein than leukocyte-derived foam cells in both sexes. Conclusions: Contrary to our hypothesis, SMCs contribute the majority of foam cells in ApoE -/- mouse atherosclerosis. Impaired ABCA1 expression in SMC foam cells, as seen in human intimal SMC foam cells, suggests a likely mechanism for preferential SMC foam cell development in both species, and a potential target for atherosclerosis treatment and prevention.
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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) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.032 | 0.012 |
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".