Age‐related dysfunction in the satellite cell niche
Notice bibliographique
Résumé
Skeletal muscle satellite cells (SC) are important for maintenance and repair of myofibers. SC function and responsiveness is regulated, at least in part, through interactions with niche components in which they reside. Recent evidence suggests that structural changes occur in the SC niche as a function of aging. In the present study, we aimed to investigate whether age has an impact on the properties of the SC niche. Muscle biopsies were obtained from the vastus lateralis of previously untrained but otherwise healthy young men (YM: 21±0.4 yrs; n=10) and old men (OM: 66±0.9 yrs; n=11) at rest. In addition, OM (n =10) performed a single bout of resistance exercise and additional muscle biopsies were taken 24 h and 48 h post‐exercise. Skeletal muscle SC niche measurements were assessed using high resolution immunofluorescent and confocal microscopy. We report changes in the muscle SC niche with aging and that many of these differences are primarily associated with type II fibres. Type II SC niche laminin thickness was significantly greater in OM (1.86 ± 0.06 μm) as compared to YM (1.55 ± 0.09 μm, p<0.05). Mean intensity of collagen IV was significantly lower in OM (92 ± 10 a.u) as compared to YM (512 ± 17 a.u, p<0.05). In OM, the fibrotic index as measured by Masson's trichrome staining was greater (3.6 ± 0.5 %) at baseline, as compared to YM (2.0 ± 0.5 %; p<0.05). We also observed the presence of SC fully incarcerated by the basal lamina. At baseline, 100% of OM possessed SC that were incarcerated, as compared to ~40% of YM. The percentage of SC in mixed muscle that were incarcerated by laminin was greater in OM (19.0 ± 1.6%) as compared to YM (7.2 ± 2.1; p<0.05). Although this phenomenon was present in both Type I and Type II fibres, it appeared exaggerated in Type I fibres (OM: 28.4 ± 8.2%, YM: 3.6 ± 2.1%; p<0.05). In all cases the greatest proportion of active SC were found in the non‐incarcerated population, whereas incarcerated cells were less likely to activate (24 h post exercise – Non‐incarcerated:32 ± 6% active, Incarcerated: 8 ± 2% active, p<0.05). Consistent with this, at 24 h, there was a significantly lower number of quiescent SC in the non‐incarcerated condition (62 ± 7 %) as compared to the incarcerated condition (92 ± 4%, p<0.05). Additional evidence of age‐related dysfunction includes larger myonuclear CSA, increased expression of C OL4 α 1 mRNA and Laminin subunits α2 and β1 was significantly greater in OM as compared to YM. Together this data suggests there are age‐related changes in the niche that are potentially detrimental to SC function and skeletal muscle health. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .
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 | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| 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 ».