Circulating Endothelial Progenitor Cells (EPCs): Variability between Normal Individuals as Measured by a New Standardized, Functional 5-Day In Vitro Colony Assay.
Notice bibliographique
Résumé
Abstract Endothelial cells derived from pre-existing blood vessels are believed to be responsible for minor repairs to the peripheral vasculature; however, a more primitive circulating EPC is thought to contribute to the maintenance and repair of heart tissue and may be useful in treating more significant vascular injuries as well as myocardial infarcts. While numerous attempts to identify the antigen expression of endothelial precursors have been made, to date no conclusive in vitro functional assays have correlated with the proposed phenotypes. Although the exact phenotype of the precursor cell remains elusive, a recently described colony assay for EPCs showed an inverse correlation between the number of circulating colony-forming cells (CFCs) and the risk of cardiovascular disease (Hill et al., NEJM 348(7):2003). This suggests that the precursor cells that read out in this colony assay may play a role in cardiac tissue maintenance and repair. For this assay to be useful in research and clinical studies, the variability in the frequency of circulating EPCs in the general population needs to be determined. We evaluated the EPC number in peripheral blood (PB) of volunteer male (n = 18) and female (n = 13) donors from the general population (age range 23–54, median age 34 years). PB white blood cell counts (WBC) were determined and mononuclear cell fractions were obtained by Ficoll® gradient density centrifugation. Following cell washing, 5 x 106 cells per well were plated in EndoCult™ medium in a 6-well fibronectin coated (FN) plate and incubated for 48 hours. Non-adherent cells were then harvested and replicate cultures were initiated with 1 x 106 cells per well in a 24-well FN plate. EPC derived colonies, consisting of a central core of round cells and more elongated cells at the periphery, were enumerated following an additional 3 days in culture. The frequency of EPCs in PB varied between individuals with a range of 0 to 99 and a mean ± SD of 25 ± 23 per ml of blood. The frequency of EPCs did not correlate with either WBC (r = 0.199) or age (r = −0.083) for either gender. In a subset of individuals studied (n = 5), fluctuations in the frequency of EPCs were determined at multiple time points over an 8-month period. Two of 5 donors consistently had less than 10 EPCs per ml of blood, whereas the other 3 donors never had less than 20 EPCs per ml of blood. These results show that, while there is a relatively large variation in the frequency of EPCs between individuals in the general population, an individual’s colony content is quite consistent over time. In conclusion, the lack of temporal variability in the frequency of circulating EPCs within an individual supports the use of this standardized 5-day EPC assay for the measurement of differences in endothelial progenitor content between individual patients. As these endothelial progenitors may have a clinical association with cardiovascular health, this standardized functional assay could be useful for further comparative clinical trials across multiple centers.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,002 | 0,002 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».