Project description:Background: The aim of this study is to improve our understanding of the mechanisms underlying the sparing of masticatory muscles relative to limb muscles in ICU patients with acute quadriplegic myopathy (AQM) by using a unique porcine ICU model, i.e., 5-day longitudinal experiments where animals are sedated, mechanically ventilated and exposed to factors triggering AQM, such as muscle unloading, endotoxin-induced sepsis, and systemic exposure to CS and NMBA. Results: An altered expression was notably observed in heat-shock proteins genes, sarcomeric proteins and myostatin genes were noticed. Hence, modifications in heat-shock proteins, sarcomeric proteins and myostatin genes are in sharp contrast to alterations in the limb muscles and it is postulated that elevated heat-shock proteins and decreased sarcomeric protein and myostatin genes play a protective role in the masticatory muscle relative to limb muscle in ICU patients with AQM. Conclusions: This intervention had no significant effect on masseter muscle fiber size or force-generation capacity. This is in sharp contrast to the dramatic decrease observed in specific force in limb muscle fibers from the same animals. However, significant differences were observed between the craniofacial and the limb muscle with a masseter muscle specific regulation of i) transcriptional and growth factors like RUNX1, FOXO1A, TBX1, PGC1-β and myostatin, ii) several heat shock protein genes like HSP 90, HSP 105/110 and αB-crystallin, iii) a matrix metalloproteinase inhibitor (TIMP2) and iv) oxidative stress responsive elements such as SRXN1 and SOD2. These muscle-type specific differences, the alterations in heat shock protein, sarcomeric protein and myostatin genes are forwarded as important factors underlying the sparing of masticatory muscles compared with limb muscles in critically ill ICU patients with Acute Quadriplegic Myopathy. Keywords: Treatment, immobilization, muscle function.
Project description:We recently generated a novel genetically engineered pig model displaying the fundamental biochemical, clinical and pathological hallmarks of human DMD. To get insight into the hierarchy of molecular derangements during progression of muscular dystrophy, we performed a label free proteome analysis of biceps femoris muscle samples from 2-day-old and 3-month-old DMD and WT pigs.
Project description:We used phosphoproteomic profiling of slow-twitch (soleus, SOL) and fast-twitch (biceps femoris, BF) muscle to identify differences between these muscle types.
Project description:Background: The aim of this study is to improve our understanding of the mechanisms underlying the sparing of masticatory muscles in ICU patients with acute quadriplegic myopathy (AQM) by using a unique porcine ICU model, i.e., 5-day longitudinal experiments where animals are sedated, mechanically ventilated and exposed to factors triggering AQM, such as muscle unloading, endotoxin-induced sepsis, and systemic exposure to CS and NMBA. Results: An increased expression was notably observed in atrogin-1, cathepsins, FoxO1a, runx1 and heat-shock proteins genes. A decreased expression in some sarcomeric proteins and myostatin genes was also noticed. Hence, modifications in heat-shock proteins and myostatin genes are in sharp contrast to alterations in the limb muscles and it is postulated that elevated heat-shock proteins and decreased myostatin genes play a protective role in the masticatory muscle in ICU patients with AQM. Conclusions: We have observed a general down-regulation of muscle proteins and myostatin. Genes involved in the UPS system, cathepsins, RUNX1, TBX1, TIMP2 and transcripts of heat-shock proteins were up-regulated. However, we have neither observed a decrease in fiber CSA or force generation, suggesting that the expected atrophic changes have been countered by a protective mechanism and myostatin downregulation. Five female domestic piglets were treated with non-depolarizing neuromuscular blocking agents (NMBA), corticosteroids(CS) and sepsis. Five female piglets were untreated.
Project description:Three male 8-week-old Wistar rats were used. The peroneal nerve of the animals was transected and sutured to the biceps femoris muscle. Four weeks later, the proximal stump was sutured to the distal stump. The animals survived for 8 weeks. All experiments were performed under Ketanest (ketamine hydrochloride, Essex Pharma GmbH, Munich, Germany; 100 mg/kg) and Rompun (xylazine hydrochloride, Bayer, Leverkusen, Germany; 10 mg/kg) anesthesia. Both substances were injected intraperitoneally. RNA was extracted from the ipsilateral and contralateral tibialis anterior muscles of each animal. The gene array analysis compared the ipsilateral muscle with the contralateral muscle of each animal. Keywords: parallel sample
Project description:Three male 8-week-old Wistar rats were used. The peroneal nerve of the animals was transected and sutured to the biceps femoris muscle. Four weeks later, the proximal stump was sutured to the distal stump. The animals survived for 8 weeks. All experiments were performed under Ketanest (ketamine hydrochloride, Essex Pharma GmbH, Munich, Germany; 100 mg/kg) and Rompun (xylazine hydrochloride, Bayer, Leverkusen, Germany; 10 mg/kg) anesthesia. Both substances were injected intraperitoneally. RNA was extracted from the ipsilateral and contralateral tibialis anterior muscles of each animal. The gene array analysis compared the ipsilateral muscle with the contralateral muscle of each animal.
Project description:Iberian ham production includes both purebred (IB) and Duroc-crossbred (IBxDU) Iberian pigs, which show important differences in meat quality and production traits, such as muscle growth and fatness. This experiment was conducted to investigate gene expression differences, transcriptional regulation and genetic polymorphisms that could be associated with the observed phenotypic differences between IB and IBxDU pigs. Nine IB and 10 IBxDU pigs were slaughtered at birth. Morphometric measures and blood samples were obtained and samples from Biceps femoris muscle were employed for compositional and transcriptome analysis by RNA-Seq technology. Phenotypic differences were evident at this early age, including greater body size and weight in IBxDU and greater Biceps femoris intramuscular fat and plasma cholesterol content in IB newborns. We detected 150 differentially expressed genes between IB and IBxDU neonates (p < 0.01 and Fold-Change > 1. 5). Several were related to adipose and muscle tissues development (DLK1, FGF21 or UBC). The functional interpretation of the transcriptomic differences revealed enrichment of functions and pathways related to lipid metabolism in IB and to cellular and muscle growth in IBxDU. Protein catabolism, cholesterol biosynthesis and immune system were functions enriched in both genotypes. We identified transcription factors potentially affecting the observed gene expression differences. Some of them have known functions on adipogenesis (CEBPA, EGRs), lipid metabolism (PPARGC1B) and myogenesis (FOXOs, MEF2D, MYOD1), which suggest a key role in the meat quality differences existing between IB and IBxDU hams. We also identified several polymorphisms showing differential segregation between IB and IBxDU pigs. Among them, non-synonymous variants were detected in several transcription factors as PPARGC1B gene, which could be associated to altered gene function. Taken together, these results provide information about candidate genes, metabolic pathways and genetic polymorphisms potentially involved in phenotypic differences between IB and IBxDU associated to meat quality and production traits.