Low-dose insulin-like growth factor binding proteins 1 and 2 and angiopoietin-like protein 3 coordinately stimulate ex vivo expansion of human umbilical cord blood hematopoietic stem cells as assayed in NOD/SCID gamma null mice
Bibliographic record
Abstract
INTRODUCTION: Insulin-like growth factors (IGFs), IGF binding proteins (IGFBPs) and angiopoietin-like proteins (ANGPTLs) can enhance the ex vivo expansion of hematopoietic stem cells (HSCs) when used with a standard cytokine cocktail of stem cell factor (SCF), thrombopoietin (TPO) and FLT3 ligand (FL). In order to determine the optimal dose and combination of IGFs, IGFBPs and ANGPTLs, serial dilution and full permutation of IGFBP1, IGFBP2, IGF2 and ANGPTL3 were applied on a cryopreserved umbilical cord blood mononuclear cell (UCB-MNC) ex vivo expansion system. METHODS: In this system, 4 × 105 cells/ml of UCB-MNCs were inoculated in serum-free Stemspan® medium (Stemcell technologies, vancouver, BC, Canada) supplied with standard basal cytokine combination of 100 ng/ml SCF, 50 ng/ml FL and 100 ng/ml TPO and supported by a bone marrow mesenchymal stromal cell layer. RESULTS: Paradoxically, experiment results showed that the highest expansion of CD34+CD38-CD90+ primitive progenitor was stimulated by cytokine combination of SCF + TPO + FL + IGFBP1 + IGFBP2 + ANGPTL3 at a low dose of 15 ng/ml IGFBP1 and 20 ng/ml IGFBP2 and ANGPTL3. This ex vivo expansion was further validated in 8-week-old to 10-week-old nonobese diabetic/severe combined immunodeficiency interleukin 2 gamma chain null (NOD/SCID-IL2Rγ-/-) mice. Limiting dilution assay showed excellent correlation between the HSC ex vivo surface marker of CD34+CD38-CD90+ and the in vivo competitive repopulating unit (CRU) functional assay. CONCLUSION: IGFBP1, IGFBP2, IGF2 and ANGPTL3 can stimulate the expansion of CD34+CD38-CD90+ primitive progenitor at low dose. The optimal combination comprises IGFBP1, IGFBP2 and ANGPTL3 together with the standard cytokine cocktail of SCF, FL and TPO. The CD34+CD38-CD90+ phenotype can serve as a surrogate ex vivo surface marker for HSCs due to consistency with the in vivo CRU functional assay.
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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 | 0.000 | 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) | 0.001 | 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".