Effects of enhanced external counterpulsation on skeletal muscle gene expression in patients with severe heart failure
ABSTRACT: Male patients (n=6, mean age 62 years) with NYHA III-IV and an left ventricular ejection fraction of <35% despite pharmacological therapy received 35 hours of enhanced external counterpulsation (EECP) over a period of 7 weeks. Before and after treatment, lateral vastus muscle biopsies were obtained and skeletal muscle gene expression was evaluated using the Affymetrix HuGene 1.0 platform. Skeletal muscle gene expression before and after treatment with enhanced external counterpulsation for 7 weeks in 6 male patients with severe heart failure
Project description:Septic patients treated in the intensive care unit (ICU) often develop multiple organ failure including persistent skeletal muscle dysfunction which results in the patient’s protracted recovery process. We have demonstrated that muscle mitochondrial enzyme activities are impaired in septic ICU patients resulting in decreased cellular energy which will interfere with muscle function and metabolism. Here we use detailed phenotyping and genomics to elucidate mechanisms leading to these impairments. Methodology/Principle Findings Utilising biopsy material from seventeen patients and ten age-matched controls we demonstrate that neither mitochondrial in vivo protein synthesis nor expression of mitochondrial genes are compromised. Indeed, there was partial activation of the mitochondrial biogenesis pathway involving NRF2?/GABP and its target genes TFAM, TFB1M and TFB2M yet clearly this failed to maintain mitochondrial function. We therefore utilised transcript profiling and pathway analysis of ICU patient skeletal muscle to generate insight into the molecular defects driving loss of muscle function and metabolic homeostasis. Gene ontology analysis of Affymetrix analysis demonstrated substantial loss of muscle specific genes, a global oxidative stress response related to most probably cytokine signalling, altered insulin related signalling and a substantial overlap between patients and muscle wasting/inflammatory animal models. MicroRNA 21 processing appeared defective suggesting that post-transcriptional protein synthesis regulation is altered by disruption of tissue microRNA expression. Finally, we were able to demonstrate that the phenotype of skeletal muscle in ICU patients is not merely one of inactivity, it appears to be an actively remodelling tissue, influenced by several mediators, all of which may be open to manipulation with the aim to improve clinical outcome. Conclusions/Significance This first combined protein and transcriptome based analysis of human skeletal muscle obtained from septic patients demonstrated that losses of mitochondria and muscle mass are accompanied by sustained protein synthesis (anabolic process) while dysregulation of transcription programmes appears to fail to compensate for increased damage and proteolysis. Our analysis identified both validated and novel clinically tractable targets to manipulate these failing processes and pursuit of these could lead to new potential treatments. Experiment Overall Design: 13 septic samples, 8 controls
Project description:The few investigations on exercise-induced global gene expression responses in human skeletal muscle haves typically focused at one specific mode of exercise and few such studies have implemented control measures. However, interpretation on distinct phenotype regulation necessitate comparison between essentially different modes of exercise and the ability to identify true exercise effects, necessitate implementation of independent non-exercise control subjects. Furthermore, muscle transkriptometranscriptome data made available through previous exercise studies can be difficult to extract and interpret by individuals that are inexperienced with bioinformatic procedures. In a comparative study, we; (1) investigated the human skeletal muscle transcriptome response to differentiated exercise and non-exercise control intervention, and; (2) aimed to develop a straightforward search tool to allow for easy extraction and interpretation of our data. We provide a simple spreadsheet containing transcriptome data allowing other investigators to see how mRNA of their interest behave in skeletal muscle following exercise, both endurance, strength and non-exercise. Our approach, allow investigators easy access to information on genuine transcriptome effects of differentiated exercise, to better aid hyporthesis-driven question in this particular field of research. 18 subjects were divided into 3 groups, performing 12 weeks of Endurance or Strength training or no training. Biopsies for microarray were take before (Pre) and 2½ and 5 hours after the last training session. Isolated RNA from these biopsies were then measured with the Affymetrix Human Gene 1.0 ST arrays.
Project description:Background: Exercising is know to have an effect on exercising skeletal muscle, but unkown is the effect on non-exercising skeletal muscle. Gene expression changes in the non-exercising skeletal muscle would point to a signalling role of skeletal muscle 9 healthy middle-aged men performed 1 hour of one-legged exercise, before and afterwards muscle biopsies were taken from both legs. Skeletal muscle biopsies were analyzed by microarray.
Project description:Dietary fat quality may influence skeletal muscle lipid handling and fat accumulation, thereby modulating insulin sensitivity. Objective: To examine acute effects of meals with various fatty acid (FA) compositions on skeletal muscle FA handling and postprandial insulin sensitivity in obese insulin resistant men. Design: In a single-blinded randomized crossover study, 10 insulin resistant men consumed three high-fat mixed-meals (2.6MJ). Meals were high in saturated FA (SFA), in monounsaturated FA (MUFA) or in polyunsaturated FA (PUFA). Fasting and postprandial skeletal muscle FA handling were examined by measuring arterio-venous concentration differences across forearm muscle. [2H2]-palmitate was infused intravenously to label endogenous triacylglycerol (TAG) and FFA in the circulation and [U-13C]-palmitate was added to the meal to label chylomicron-TAG. Skeletal muscle biopsies were taken to assess intramuscular lipid metabolism and gene expression. Results: Insulin and glucose responses (AUC) after SFA meal were significantly higher compared with PUFA meal (p=0.003 and 0.028, respectively). Uptake of TAG-derived FA was significantly lower in the early postprandial phase after PUFA meal as compared with other meals (AUC60-120, p<0.001). The PUFA meal induced less transcriptional downregulation of oxidative pathways compared with other meals. The fractional synthetic rate was higher in DAG and PL fraction after MUFA and PUFA meal. Conclusion: Intake of a PUFA meal reduced TAG-derived skeletal muscle FA uptake, which was accompanied by higher postprandial insulin sensitivity and a tendency towards a higher muscle lipid turnover. These data suggest that the effects of replacement of SFA by PUFA may contribute to less muscle lipid uptake and may be therefore protective against the development of insulin resistance. Keywords: expression profiling by array randomized crossover dietary intervention study
Project description:Skeletal myocytes are metabolically active and susceptible to insulin resistance, thus implicated in type 2 diabetes (T2D). This complex disease involves systemic metabolic changes and their elucidation at the systems level requires genome-wide data and biological networks. Genome-scale metabolic models (GEMs) provide a network-context to integrate high-throughput data. We generated myocyte-specific RNA-seq data and investigated their correlation with proteome data. These data were then used to reconstruct a comprehensive myocyte GEM. Next, we performed a meta-analysis of six studies comparing muscle transcription in T2D versus healthy subjects. Transcriptional changes were mapped on the myocyte GEM, revealing extensive transcriptional regulation in T2D, particularly around pyruvate oxidation, branched-chain amino acid catabolism, and tetrahydrofolate metabolism, connected through the down-regulated dihydrolipoamide dehydrogenase. Strikingly, the gene signature underlying this metabolic regulation successfully classifies the disease state of individual samples, suggesting that regulation of these pathways is a ubiquitous feature of myocytes in response to T2D. Isolated skeletal muscle precursor cells from six normal glucose tolerant and non-obese males and females were differentiated in vitro. RNA from fully differentiated myotubes was sequenced using RNA-seq.
Project description:Background: Exercise has a positive effect on overall health. This study was performed to get an overview of the effects of mixed exercise training on skeletal muscl 18 middle-aged men performed 12 weeks of exercise training (2x endurance training and 1x resistance training), muscle biopsies were taken at baseline and 3 days after the last training session
Project description:Eccentric exercise (ECC) can result in ultra-structural and histological damage to skeletal muscle. The damage incurred following ECC is typically followed by a subsequent regenerative and adaptive response. The specific mechanisms that drive this response, particularly in human muscle, are not well understood. The objective of this study was to characterize the early molecular response in skeletal muscle following ECC in humans. We used an Agilent whole human genome microarray to assess global gene expression in male subjects (N=35) at 3 hours post-100 eccentric contractions of the knee extensors. ANCOVA (age and BMI covariates) was used to compare mRNA expression between the ECC and non-exercised (CON) legs of each subject. Novel transcripts from IPA identified networks were confirmed with quantitative real-time (qRT)-PCR. qRT-PCR analysis of 3 of these transcripts (IkBα, TNFRSF1A and ICAM-1) confirmed changes observed in the microarray analysis. 35 male subjects performed an eccentric exercise protocol consisting of 100 maximal eccentric contrations of the knee extensors. 3 hours after the completion of the exercise regimen, a muscle biopsy was taken from the vastus lateralis of both legs. The non-exercised leg served as the control. Gene expresssion was analyzed using an ANCOVA, with covariates for age and BMI.
Project description:Myotonic Dystrophy Type-2 (DM2) is an autosomal dominant disease caused by the expansion of a CCTG tetraplet repeat. It is a multisystemic disorder, affecting skeletal muscles, the heart, the eye, the central nervous system and the endocrine system. Whole mRNAs expression was measured in the muscle of DM2 patients and compared it to controls.We identified distinct genes modulated in DM2 patients compared to controls. Our study included 10 DM2 and 10 control (CTR) muscle biopsies from biceps brachii. DM2 and CTR were age- and sex- matched. Most DM2 patients had myotonia and cataract, two disease hallmarks, while differences in other clinical parameters (muscle strenght, diabetes, CPK, FT3, FT4, TSH, ejection fraction) were not significant. Genes expression was assessed by Affymetrix Gene Chip Human Exon 1.0 ST Array.
Project description:The skeletal muscle development in swine begins at embryogenesis. Simultaneously, 24,123 probe-sets were screened, analysed for differential expression between different breeds (german landrace and pietrain) at different stages of development (35, 63, 91 dpc and adult stage). RNAs of skeletal muscle from german landrace and pietrain at 35, 63, 91 dpc and adult stages were hybridized to Affymetrix GeneChip Porcine Genome Array.
Project description:Tfr1 is important for iron uptake in red blood cells. We deleted Tfr1 in skeletal muscle to determine the role of Tfr1 in iron uptake in skeletal muscle. We used microarrays to identify global gene changes associated with deletion of Tfr1 in skeletal muscle We used skeletal muscle and liver from wild type and Tfr1 skeletal muscle KO mice at postnatal day 5 and postnatal day 9. mRNA was extracted from the tissues, labaled and hibridized to Affymetrics microarrays.