ArticlePloS one2019
Skeletal muscles of hibernating black bears show minimal atrophy and phenotype shifting despite prolonged physical inactivity and starvation.
Article in PloS one, 2019. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 20 papers, 1 of them a synthesis that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
20 citing papers in PubMed, 1 synthesis or guideline pooled it, 39 citations in OpenAlex.
- Pooled it
- Type-specific and hibernation-associated skeletal muscle remodeling of the back muscle in Syrian hamsters.The journal of physiological sciences : JPS · 2026Article
- Molecular mediators of cold adaptation in mammalian cells.Communications biology · 2025Review
- A review on ecological and physiological studies in bears from a One Health perspective.The Journal of veterinary medical science · 2025Review
- Harnessing hibernation: Unlocking nature's secrets for advances in healthy aging, critical care, and space exploration.Annals of the New York Academy of Sciences · 2025Review
- Mitochondrial-derived gene expression in hibernation: tissue-specific responses in the thirteen-lined ground squirrel.Open biology · 2025Article
- The utility of animal models to inform the next generation of human space exploration.NPJ microgravity · 2025Review
- MicroRNA, Myostatin, and Metabolic Rate Depression: Skeletal Muscle Atrophy Resistance in HibernatingCells · 2024Article
- Molecular regulation of reversible cardiac remodeling: lessons from species with extreme physiological adaptations.The Journal of experimental biology · 2024Review
- Article
- Plasticity changes in iron homeostasis in hibernating Daurian ground squirrels (Spermophilus dauricus) may counteract chronically inactive skeletal muscle atrophy.Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology · 2024Article
- Proteomic Identification of Seasonally Expressed Proteins Contributing to Heart Function and the Avoidance of Skeletal Muscle Disuse Atrophy in a Hibernating Mammal.Journal of proteome research · 2024Article
- Article
- Regulation of protein and oxidative energy metabolism are down-regulated in the skeletal muscles of Asiatic black bears during hibernation.Scientific reports · 2022Article
- Article
- Maternal protein restriction changes structural and metabolic gene expression in the skeletal muscle of aging offspring rats.Histology and histopathology · 2021Article
- mTOR Signaling in Metabolic Stress Adaptation.Biomolecules · 2021Review
- Ascorbic Acid Supplementation Improves Skeletal Muscle Growth in Pacu (International journal of molecular sciences · 2021Article
- Changes in liver microRNA expression and their possible regulatory role in energy metabolism-related genes in hibernating black bears.Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology · 2021Article
- Body Protein Sparing in Hibernators: A Source for Biomedical Innovation.Frontiers in physiology · 2021Review
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
3 authors at 2 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Hibernating mammals experience prolonged periods of torpor and starvation during winter for up to 5-7 months. Though physical inactivity and malnutrition generally lead to profound loss of muscle mass and metabolic dysfunction in humans, hibernating bears show limited muscle atrophy and can successfully maintain locomotive function. These physiological features in bears allow us to hypothesize that hibernating bears uniquely alter the regulation of protein and energy metabolism in skeletal muscle which then contributes to "muscle atrophy resistance" against continued physical inactivity. In this study, alteration of signaling pathways governing protein and energy metabolisms was examined in skeletal muscle of the Japanese black bear (Ursus thibetanus japonicus). Sartorius muscle samples were collected from bear legs during late November (pre-hibernation) and early April (post-hibernation). Protein degradation pathways, through a ubiquitin-proteasome system (as assessed by increased expression of murf1 mRNA) and an autophagy-dependent system (as assessed by increased expression of atg7, beclin1, and map1lc3 mRNAs), were significantly activated in skeletal muscle following hibernation. In contrast, as indicated by a significant increase in S6K1 phosphorylation, an activation state of mTOR (mammalian/mechanistic target of rapamycin), which functions as a central regulator of protein synthesis, increased in post-hibernation samples. Gene expression of myostatin, a negative regulator of skeletal muscle mass, was significantly decreased post-hibernation. We also confirmed that the phenotype shifted toward slow-oxidative muscle and mitochondrial biogenesis. These observations suggest that protein and energy metabolism may be altered in skeletal muscle of hibernating bears, which then may contribute to limited loss of muscle mass and efficient energy utilization.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.