Imperial College London

Dr Amanda Sathyapala

Faculty of MedicineNational Heart & Lung Institute

Clinical Senior Lecturer
 
 
 
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a.sathyapala

 
 
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305Guy Scadding BuildingRoyal Brompton Campus

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Summary

 

Publications

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Kasetti P, Husain NF, Skinner TC, Asimakopoulou K, Steier J, Sathyapala SAet al., 2024, Personality traits and pre-treatment beliefs and cognitions predicting patient adherence to continuous positive airway pressure: A systematic review., Sleep Med Rev, Vol: 74

Adherence to Continuous Positive Airway Pressure (CPAP) for obstructive sleep apnoea (OSA) can be improved by behavioural interventions which modify patients' beliefs and cognitions about OSA, CPAP, and themselves. We have conducted the first systematic review of the literature on beliefs and cognitions held before starting treatment, and personality (which influences the former) that predict the decision to purchase or start CPAP, or CPAP adherence one month or more after CPAP initiation. A systematic search and screen of articles identified 21 eligible publications from an initial 1317. Quality assessment performed using an adapted Newcastle-Ottawa Scale demonstrated that 13 (62%) studies were poor quality and only seven (33%) were high quality. Eighteen factors, such as self-efficacy (confidence) in using CPAP and value placed on health predicted CPAP adherence; however, for only six (33%), utility as an intervention target is known, from calculation of individual predictive power. Studies did not use new behavioural frameworks effective at explaining adherence behaviours, nor did they interview patients to collect in-depth data on barriers and facilitators of CPAP use. Future studies cannot have these limitations if high quality evidence is to be generated for intervention development, which is currently sparse as highlighted by this review.

Journal article

Kasetti P, Husain NF, Jesuraj N, Skinner T, Asimakopoulou K, Steier J, Sathyapala SAet al., 2022, Development of a pre-treatment questionnaire for obstructive sleep apnoea patients predicting use of early continuous positive airway pressure therapy and risk of long-term non-adherence, European Sleep Research Society, Publisher: WILEY, ISSN: 0962-1105

Conference paper

Dielesen J, Ledwaba-Chapman LJ, Husain NF, Skinner TC, Kasetti P, Pengo MF, Whiteman T, Asimakopoulou K, Merritt S, Jones D, Dickel P, Pulakal S, Ward N, Pepperell J, Steier J, Sathyapala Aet al., 2022, A novel classification of obstructive sleep apnoea enabling precision medicine to improve adherence to continuous positive airway pressure: a growth mixture modelling analysis, Publisher: WILEY, ISSN: 0962-1105

Conference paper

Sathyapala SA, Rochester A, Kemp PR, Brightling C, Steiner M, Polkey MIet al., 2019, P126 Female COPD patients have a greater prevalence of a low muscle mass and weaker quadriceps muscles than male patients, Winter Meeting of the British-Thoracic-Society, Publisher: BMJ Publishing Group, Pages: A159-A159, ISSN: 0040-6376

Conference paper

Ciano M, Mantellato G, Connolly M, Paul-Clark M, Mitchell J, Wilson-Owen S, Cookson W, Moffatt M, Hughes S, Polkey M, Kemp P, Natanek Set al., 2019, EGF receptor (EGFR) inhibition promotes a slow-twitch oxidative, over a fast-twitch, muscle phenotype, Scientific Reports, Vol: 9, ISSN: 2045-2322

A low quadriceps slow-twitch (ST), oxidative (relative to fast-twitch) fiber proportion is prevalent in chronic diseases such Chronic Obstructive Pulmonary Disease (COPD) and is associated with exercise limitation and poor outcomes. Benefits of an increased ST fiber proportion are demonstrated in genetically modified animals. Pathway analysis of published data of differentially expressed genes in mouse ST and FT fibers, mining of our microarray data and a qPCR analysis of quadriceps specimens from COPD patients and controls were performed. ST markers were quantified in C2C12 myotubes with EGF-neutralizing antibody, EGFR inhibitor or an EGFR-silencing RNA added. A zebrafish egfra mutant was generated by genome editing and ST fibers counted. EGF signaling was (negatively) associated with the ST muscle phenotype in mice and humans, and muscle EGF transcript levels were raised in COPD. In C2C12 myotubes, EGFR inhibition/silencing increased ST, including mitochondrial, markers. In zebrafish, egfra depletion increased ST fibers and mitochondrial content. EGF is negatively associated with ST muscle phenotype in mice, healthy humans and COPD patients. EGFR blockade promotes the ST phenotype in myotubes and zebrafish embryos. EGF signaling suppresses the ST phenotype, therefore EGFR inhibitors may be potential treatments for COPD-related muscle ST fiber loss.

Journal article

Farre-Garros R, Lee J, Natanek S, Connolly M, Sayer A, Patel H, Cooper C, Polkey M, Kemp Pet al., 2019, Quadriceps miR-542-3p and 5p are elevated in COPD and reduce function by inhibiting ribosomal and protein synthesis, Journal of Applied Physiology, Vol: 126, Pages: 1514-1524, ISSN: 8750-7587

Reduced physical performance reduces quality of life in patients with COPD. Impaired physical performance is, in part, a consequence of reduced muscle mass and function, which is accompanied by mitochondrial dysfunction. We recently showed that miR-542-3p and miR-542-5p were elevated in a small cohort of COPD patients and more markedly in critical care patients. In mice these miRNAs promoted mitochondrial dysfunction suggesting that they would affect physical performance in patients with COPD but we did not explore the association of these miRNAs with disease severity or physical performance further. We therefore quantified miR-542-3p/5p and mitochondrial rRNA expression in RNA extracted from quadriceps muscle of patients with COPD and determined their association with physical performance. As miR-542-3p inhibits ribosomal protein synthesis its ability to inhibit protein synthesis was also determined in vitro.Both miR-542-3p and -5p expression were elevated in patients with COPD (5-fold p<0.001) and the degree of elevation associated with impaired lung function (TLCO% and FEV1%) and physical performance (6-minute walk distance %). In COPD patients, the ratio of 12S rRNA to 16S rRNA was suppressed suggesting mitochondrial ribosomal stress and mitochondrial dysfunction and miR-542-3p/5p expression was inversely associated with mitochondrial gene expression and positively associated with p53 activity. miR-542-3p suppressed RPS23 expression and maximal protein synthesis in vitro. Our data show that miR-542-3p and -5p expression is elevated in COPD patients and may suppress physical performance at least in part by inhibiting mitochondrial and cytoplasmic ribosome synthesis and suppressing protein synthesis.

Journal article

Sharanya A, Ciano M, Withana S, Polkey M, Kemp P, Natanek Set al., 2019, Sex differences in COPD-related quadriceps muscle dysfunction and fibre abnormalities, Chronic Respiratory Disease, Vol: 16, Pages: 1-13, ISSN: 1479-9723

Background: In COPD, lower limb dysfunction is associated with reduced exercise capacity, increased hospitalisations and mortality. We investigated sex differences in the prevalence of quadriceps dysfunction and fibre abnormalities in a large COPD cohort, controlling for the normal sex differences in health. Methods: We compared existing data from 76 male and 38 female COPD patients where each variable was expressed as a function of gender-specific normal values (obtained from 16 male and 14 female controls). Results: Female COPD patients had lower quadriceps muscle strength and peak workload on a maximal incremental cycle ergometry protocol compared to male patients. Female patients had a smaller type II fibre cross-sectional area (CSA) compared to male patients, suggesting a greater female preponderance to fibre atrophy, although this result was largely driven by a few male patients with increased type II fibre CSA. Female patients had significantly higher concentrations of a number of plasma pro-inflammatory cytokines including tumor necrosis factor alpha (TNFα) and interleukin 8 (IL8), but not lower levels of physical activity or arterial oxygenation, compared to males. Conclusions: Our data confirms results from a previous small study and suggests that female COPD patients have a greater prevalence of muscle wasting and weakness. Larger studies investigating sex differences in COPD-related muscle atrophy and weakness are needed, as the results will have implications for monitoring in clinical practice and for design of clinical trials evaluating novel muscle anabolic agents.

Journal article

Willis-Owen SAG, Thompson AR, Kemp P, Moffatt MF, Polkey M, Cookson W, Natanek Set al., 2018, COPD is accompanied by co-ordinated transcriptional perturbation in the quadriceps affecting the mitochondria and extracellular matrix, Scientific Reports, Vol: 8, ISSN: 2045-2322

Skeletal muscle dysfunction is a frequent extra-pulmonary manifestation of Chronic Obstructive Pulmonary Disease (COPD) with implications for both quality of life and survival. The underlying biology nevertheless remains poorly understood. We measured global gene transcription in the quadriceps using Affymetrix HuGene1.1ST arrays in an unselected cohort of 79 stable COPD patients in secondary care and 16 healthy age- and gender-matched controls. We detected 1,826 transcripts showing COPD-related variation. Eighteen exhibited ≥2fold changes (SLC22A3, FAM184B, CDKN1A, FST, LINC01405, MUSK, PANX1, ANKRD1, C12orf75, MYH1, POSTN, FRZB, TNC, ACTC1, LINC00310, MYH3, MYBPH and AREG). Thirty-one transcripts possessed previous reported evidence of involvement in COPD through genome-wide association, including FAM13A. Network analysis revealed a substructure comprising 6 modules of co-expressed genes. We identified modules with mitochondrial and extracellular matrix features, of which IDH2, a central component of the mitochondrial antioxidant pathway, and ABI3BP, a proposed switch between proliferation and differentiation, represent hubs respectively. COPD is accompanied by coordinated patterns of transcription in the quadriceps involving the mitochondria and extracellular matrix and including genes previously implicated in primary disease processes.

Journal article

Kemp P, Connolly, Paul R, Farre Garros R, Natanek, Bloch, Lee J, lorenzo, Patel H, Cooper C, Sayer A, Wort, Griffiths, Polkeyet al., 2017, miR-424-5p reduces ribosomal RNA and protein synthesis in muscle wasting, Journal of Cachexia, Sarcopenia and Muscle, Vol: 9, Pages: 400-416, ISSN: 2190-6009

Background: A loss of muscle mass occurs as a consequence of a range of chronic and acute diseases as well as in older age. This wasting results from an imbalance of protein synthesis and degradation with a reduction in synthesis and resistance to anabolic stimulation often reported features. Ribosomes are required for protein synthesis so changes in the control of ribosome synthesis is a potential contributor to muscle wasting. MicroRNAs (miRNAs) are known regulators of muscle phenotype and have been shown to modulate components of the protein synthetic pathway. One miRNA that is predicted to target a number of components of protein synthetic pathway is miR-424-5p, which is elevated in the quadriceps of patients with chronic obstructive pulmonary disease (COPD).Methods: Targets of miR-424-5p were identified by Ago2 pull-down and the effects of the miRNA on RNA and protein expression were determined by qPCR and western blotting in muscle cells in vitro. Protein synthesis was determined by puromycin incorporation in vitro. The miRNA was over-expressed in the tibialis anterior muscle of mice by electroporation and the effects quantified. Finally, quadriceps expression of the miRNA was determined by qPCR in patients with COPD, intensive care unit acquired weakness (ICUAW), and in patients undergoing aortic surgery as well as in individuals from the Hertfordshire Sarcopenia Study.Results: Pull-down assays showed that miR-424-5p bound to mRNAs encoding proteins associated with muscle protein synthesis. The most highly enriched mRNAs encoded proteins required for the Pol I RNA pre-initiation complex (PIC) required for rRNA transcription, (PolR1A and Upstream binding transcription factor, UBTF). In vitro, miR-424-5p reduced expression of these RNAs, reduced rRNA levels and inhibited protein synthesis. In mice, over-expression of miR-322 (rodent miR-424 orthologue) caused fibre atrophy and reduced UBTF expression and rRNA levels. In humans elevated miR-424-5p as

Journal article

Kemp P, paul R, lee J, donaldson AV, connolly M, sharif M, natanek SA, rosendahl U, polkey M, griffiths Met al., 2017, miR-422a suppresses SMAD4 protein expression and promotes resistance to muscle loss, Journal of Cachexia Sarcopenia and Muscle, Vol: 9, Pages: 119-128, ISSN: 2190-5991

BackgroundLoss of muscle mass and strength are important sequelae of chronic disease, but the response of individuals is remarkably variable, suggesting important genetic and epigenetic modulators of muscle homeostasis. Such factors are likely to modify the activity of pathways that regulate wasting, but to date, few such factors have been identified.MethodsThe effect of miR-422a on SMAD4 expression and transforming growth factor (TGF)-β signalling were determined by western blotting and luciferase assay. miRNA expression was determined by qPCR in plasma and muscle biopsy samples from a cross-sectional study of patients with chronic obstructive pulmonary disease (COPD) and a longitudinal study of patients undergoing aortic surgery, who were subsequently admitted to the intensive care unit (ICU).ResultsmiR-422a was identified, by a screen, as a microRNA that was present in the plasma of patients with COPD and negatively associated with muscle strength as well as being readily detectable in the muscle of patients. In vitro, miR-422a suppressed SMAD4 expression and inhibited TGF-beta and bone morphogenetic protein-dependent luciferase activity in muscle cells. In male patients with COPD and those undergoing aortic surgery and on the ICU, a model of ICU-associated muscle weakness, quadriceps expression of miR-422a was positively associated with muscle strength (maximal voluntary contraction r = 0.59, P < 0.001 and r = 0.51, P = 0.004, for COPD and aortic surgery, respectively). Furthermore, pre-surgery levels of miR-422a were inversely associated with the amount of muscle that would be lost in the first post-operative week (r = −0.57, P < 0.001).ConclusionsThese data suggest that differences in miR-422a expression contribute to the susceptibility to muscle wasting associated with chronic and acute disease and that at least part of this activity may be mediated by reduced TGF-beta signalling in skeletal muscle.

Journal article

farre garros, paul R, connolly M, lewis A, natanek SA, garfield BE, BLoch S, Mouly V, griffiths M, polkey MI, Kemp Pet al., 2017, miR-542 promotes mitochondrial dysfunction and SMAD activity and is raised in ICU Acquired Weakness, American Journal of Respiratory and Critical Care Medicine, Vol: 196, Pages: 1-12, ISSN: 1073-449X

Rationale: Loss of skeletal muscle mass and function is a common consequence of critical illness and a range of chronic diseases but the mechanisms by which this occurs are unclear. Objectives: We aimed to identify miRNAs that were increased in the quadriceps of patients with muscle wasting and to determine the molecular pathways by which they contributed to muscle dysfunction. Methods: miR-542-3p/-5p were quantified in the quadriceps of patients with COPD and intensive care unit acquired weakness (ICUAW). The effect of miR-542-3p/5p was determined on mitochondrial function and TGF-β signaling in vitro and in vivo. Measurements and main results: miR-542-3p/5p were elevated in patients with COPD but more markedly in patients with ICUAW. In vitro, miR-542-3p suppressed the expression of the mitochondrial ribosomal protein MRPS10, and reduced 12S rRNA expression suggesting mitochondrial ribosomal stress. miR-542-5p increased nuclear phospho-SMAD2/3 and suppressed expression of SMAD7, SMURF1 and PPP2CA, proteins that inhibit or reduce SMAD2/3 phosphorylation suggesting that miR-542-5p increased TGF-β signaling. In mice, miR-542 over-expression caused muscle wasting, reduced mitochondrial function, 12S rRNA expression and SMAD7 expression, consistent with the effects of the miRNAs in vitro. Similarly, in patients with ICUAW, the expression of 12S rRNA and of the inhibitors of SMAD2/3 phosphorylation were reduced, indicative of mitochondrial ribosomal stress and increased TGF-β signaling. In patients undergoing aortic surgery, pre-operative levels of miR-542-3p/5p were positively correlated with muscle loss following surgery. Conclusion; Elevated miR-542-3p/5p may cause muscle atrophy in ICU patients through the promotion of mitochondrial dysfunction and activation of SMAD2/3 phosphorylation.

Journal article

To M, Swallow EB, Akashi K, Haruki K, Natanek SA, Polkey MI, Ito K, Barnes PJet al., 2017, Reduced HDAC2 in skeletal muscle of COPD patients, Respiratory Research, Vol: 18, ISSN: 1465-993X

BACKGROUND: Skeletal muscle weakness in chronic obstructive pulmonary disease (COPD) is an important predictor of poor prognosis, but the molecular mechanisms of muscle weakness in COPD have not been fully elucidated. The aim of this study was to investigate the role of histone deacetylases(HDAC) in skeletal muscle weakness in COPD. METHODS AND RESULTS: Twelve COPD patients, 8 smokers without COPD (SM) and 4 healthy non-smokers (NS) were recruited to the study. HDAC2 protein expression in quadriceps muscle biopsies of COPD patients (HDAC2/β-actin: 0.59 ± 0.34) was significantly lower than that in SM (1.9 ± 1.1, p = 0.0007) and NS (1.2 ± 0.7, p = 0.029). HDAC2 protein in skeletal muscle was significantly correlated with forced expiratory volume in 1 s % predicted (FEV1 % pred) (rs = 0.53, p = 0.008) and quadriceps maximum voluntary contraction force (MVC) (rs = 0.42, p = 0.029). HDAC5 protein in muscle biopsies of COPD patients (HDAC5/β-actin: 0.44 ± 0.26) was also significantly lower than that in SM (1.29 ± 0.39, p = 0.0001) and NS (0.98 ± 0.43, p = 0.020). HDAC5 protein in muscle was significantly correlated with FEV1 % pred (rs = 0.64, p = 0.0007) but not with MVC (rs = 0.30, p = 0.180). Nuclear factor-kappa B (NF-κB) DNA binding activity in muscle biopsies of COPD patients (10.1 ± 7.4) was significantly higher than that in SM (3.9 ± 7.3, p = 0.020) and NS (1.0 ± 1.2, p = 0.004and significantly correlated with HDAC2 decrease (rs = -0.59, p = 0.003) and HDAC5 (rs = 0.050, p = 0.012). HDAC2 knockdown by RNA interfe

Journal article

Lee J, Donaldson AV, Lewis A, Natanek A, Polkey, Kemp Pet al., 2017, Circulating miRNAs from imprinted genomic regions are associated with peripheral muscle strength in COPD patients, European Respiratory Journal, Vol: 49, Pages: 1-4, ISSN: 1399-3003

Journal article

Kemp P, Natanek A, 2017, Epigenetics and susceptibility to muscle wasting in COPD, Archivos de Bronconeumología, Vol: 53, Pages: 364-365, ISSN: 0300-2896

Journal article

Patel MS, Donaldson AV, Lewis A, Natanek SA, Lee JY, Andersson YM, Haji G, Jackson SG, Bolognese BJ, Foley JP, Podolin PL, Bruijnzeel PLB, Hart N, Hopkinson NS, Man WD-C, Kemp PR, Polkey MIet al., 2016, Klotho and smoking – An interplay influencing the skeletal muscle function deficits that occur in COPD, Respiratory Medicine, Vol: 113, Pages: 50-56, ISSN: 0954-6111

BackgroundKlotho is an ‘anti-ageing’ hormone and transmembrane protein; Klotho deficient mice develop a similar ageing phenotype to smokers including emphysema and muscle wasting. The objective of this study was to evaluate skeletal muscle and circulating Klotho protein in smokers and COPD patients and to relate Klotho levels to relevant skeletal muscle parameters. We sought to validate our findings by undertaking complimentary murine studies.MethodsFat free mass, quadriceps strength and spirometry were measured in 87 participants (61 COPD, 13 ‘healthy smokers’ and 13 never smoking controls) in whom serum and quadriceps Klotho protein levels were also measured. Immunohistochemistry was performed to demonstrate the location of Klotho protein in human skeletal muscle and in mouse skeletal muscle in which regeneration was occurring following injury induced by electroporation. In a separate study, gastrocnemius Klotho protein was measured in mice exposed to 77 weeks of smoke or sham air.ResultsQuadriceps Klotho levels were lower in those currently smoking (p = 0.01), irrespective of spirometry, but were not lower in patients with COPD. A regression analysis identified current smoking status as the only independent variable associated with human quadriceps Klotho levels, an observation supported by the finding that smoke exposed mice had lower gastrocnemius Klotho levels than sham exposed mice (p = 0.005). Quadriceps Klotho levels related to local oxidative stress but were paradoxically higher in patients with established muscle wasting or weakness; the unexpected relationship with low fat free mass was the only independent association. Within locomotor muscle, Klotho localized to the plasma membrane and to centralized nuclei in humans and in mice with induced muscle damage. Serum Klotho had an independent association with quadriceps strength but did not relate to quadriceps Klotho levels or to spirometric parameters.ConclusionsKlotho is expressed

Journal article

Lewis A, Donaldson AV, Natanek SA, Vaidyanathan S, Man WDC, Hopkinson NS, Sayer AA, Patel HP, Cooper C, Syddall H, Polkey MI, Kemp PRet al., 2016, Increased expression of H19/miR-675 is associated with a low fat free mass index in patients with COPD, Journal of Cachexia, Sarcopenia and Muscle, Vol: 7, Pages: 330-344, ISSN: 2190-6009

BackgroundLoss of muscle mass and strength is a significant comorbidity in patients with chronic obstructive pulmonary disease (COPD) that limits their quality of life and has prognostic implications but does not affect everyone equally. To identify mechanisms that may contribute to the susceptibility to a low muscle mass, we investigated microRNA (miRNA) expression, methylation status, and regeneration in quadriceps muscle from COPD patients and the effect of miRNAs on myoblast proliferation in vitro. The relationships of miRNA expression with muscle mass and strength was also determined in a group of healthy older men.MethodsWe identified miRNAs associated with a low fat-free mass (FFM) phenotype in a small group of patients with COPD using a PCR screen of 750 miRNAs. The expression of two differentially expressed miRNAs (miR-675 and miR-519a) was determined in an expanded group of COPD patients and their associations with FFM and strength identified. The association of these miRNAs with FFM and strength was also explored in a group of healthy community-dwelling older men. As the expression of the miRNAs associated with FFM could be regulated by methylation, the relative methylation of the H19 ICR was determined. Furthermore, the proportion of myofibres with centralized nuclei, as a marker of muscle regeneration, in the muscle of COPD patients was identified by immunofluorescence.ResultsImprinted miRNAs (miR-675 and from a cluster, C19MC which includes miR-519a) were differentially expressed in the quadriceps of patients with a low fat-free mass index (FFMI) compared to those with a normal FFMI. In larger cohorts, miR-675 and its host gene (H19) were higher in patients with a low FFMI and strength. The association of miR-519a expression with FFMI was present in male patients with severe COPD. Similar associations of miR expression with lean mass and strength were not observed in healthy community dwelling older men participating in the Hertfordshire Sarcopenia Stu

Journal article

Patel MS, Lee J, Baz M, Wells CE, Bloch S, Lewis A, Donaldson AV, Garfield B, Hopkinson NS, Natanek SA, Man W, Wells D, Baker EH, Polkey MI, Kemp Pet al., 2015, Growth differentiation factor-15 is associated with muscle mass in chronic obstructive pulmonary disease and promotes muscle wasting in vivo, Journal of Cachexia, Sarcopenia and Muscle, Vol: 7, Pages: 436-448, ISSN: 2190-6009

BackgroundLoss of muscle mass is a co-morbidity common to a range of chronic diseases including chronic obstructive pulmonary disease (COPD). Several systemic features of COPD including increased inflammatory signalling, oxidative stress, and hypoxia are known to increase the expression of growth differentiation factor-15 (GDF-15), a protein associated with muscle wasting in other diseases. We therefore hypothesized that GDF-15 may contribute to muscle wasting in COPD.MethodsWe determined the expression of GDF-15 in the serum and muscle of patients with COPD and analysed the association of GDF-15 expression with muscle mass and exercise performance. To determine whether GDF-15 had a direct effect on muscle, we also determined the effect of increased GDF-15 expression on the tibialis anterior of mice by electroporation.ResultsGrowth differentiation factor-15 was increased in the circulation and muscle of COPD patients compared with controls. Circulating GDF-15 was inversely correlated with rectus femoris cross-sectional area (P < 0.001) and exercise capacity (P < 0.001) in two separate cohorts of patients but was not associated with body mass index. GDF-15 levels were associated with 8-oxo-dG in the circulation of patients consistent with a role for oxidative stress in the production of this protein. Local over-expression of GDF-15 in mice caused wasting of the tibialis anterior muscle that expressed it but not in the contralateral muscle suggesting a direct effect of GDF-15 on muscle mass (P < 0.001).ConclusionsTogether, the data suggest that GDF-15 contributes to the loss of muscle mass in COPD.

Journal article

Maddocks M, Shrikrishna D, Vitoriano S, Natanek SA, Tanner RJ, Hart N, Kemp PR, Moxham J, Polkey MI, Hopkinson NSet al., 2014, Skeletal muscle adiposity is associated with physical activity, exercise capacity and fibre shift in COPD, European Respiratory Journal, Vol: 44, Pages: 1188-1198, ISSN: 1399-3003

Quadriceps muscle phenotype varies widely between patients with chronic obstructive pulmonary disease (COPD) and cannot be determined without muscle biopsy. We hypothesised that measures of skeletal muscle adiposity could provide noninvasive biomarkers of muscle quality in this population.In 101 patients and 10 age-matched healthy controls, mid-thigh cross-sectional area, percentage intramuscular fat and skeletal muscle attenuation were calculated using computed tomography images and standard tissue attenuation ranges: fat -190– -30 HU; skeletal muscle -29–150 HU.Mean±sd percentage intramuscular fat was higher in the patient group (6.7±3.5% versus 4.3±1.2%, p = 0.03). Both percentage intramuscular fat and skeletal muscle attenuation were associated with physical activity level, exercise capacity and type I fibre proportion, independent of age, mid-thigh cross-sectional area and quadriceps strength. Combined with transfer factor of the lung for carbon monoxide, these variables could identify >80% of patients with fibre type shift with >65% specificity (area under the curve 0.83, 95% CI 0.72–0.95).Skeletal muscle adiposity assessed by computed tomography reflects multiple aspects of COPD related muscle dysfunction and may help to identify patients for trials of interventions targeted at specific muscle phenotypes.

Journal article

Carrington DJ, Nolan CM, Dickel P, Kon SSC, Canavan JL, Jones SE, Bone EW, Clark AL, Natanek SA, Man WD-Cet al., 2014, Obstructive sleep apnoea: A new indication for pulmonary rehabilitation?, 22nd Annual Congress of the European-Respiratory-Society, Publisher: EUROPEAN RESPIRATORY SOC JOURNALS LTD, ISSN: 0903-1936

Conference paper

Patel MS, Natanek SA, Stratakos G, Pascual S, Martinez-Llorens J, Disano L, Terzis G, Hopkinson NS, Gea J, Vogiatzis I, Maltais F, Polkey MIet al., 2014, Vastus lateralis fiber shift is an independent predictor of mortality in chronic obstructive pulmonary disease, American Journal of Respiratory and Critical Care Medicine, Vol: 190, Pages: 350-352, ISSN: 1073-449X

Journal article

Patel MS, Mohan D, Andersson YM, Baz M, Kon SSC, Canavan JL, Jackson SG, Clark AL, Hopkinson NS, Natanek SA, Kemp PR, Bruijnzeel PLB, Man WD-C, Polkey MIet al., 2014, Phenotypic Characteristics Associated With Reduced Short Physical Performance Battery Score in COPD, CHEST, Vol: 145, Pages: 1016-1024, ISSN: 0012-3692

Journal article

Shrikrishna D, Tanner RJ, Lee JY, Natanek A, Lewis A, Murphy PB, Hart N, Moxham J, Montgomery HE, Kemp PR, Polkey MI, Hopkinson NSet al., 2014, A Randomized Controlled Trial of Angiotensin-Converting Enzyme Inhibition for Skeletal Muscle Dysfunction in COPD, Chest, Vol: 146, Pages: 932-940, ISSN: 1931-3543

Journal article

Mendoza L, Gogali A, Shrikrishna D, Cavada G, Kemp SV, Natanek SA, Jackson AS, Polkey MI, Wells AU, Hopkinson NSet al., 2014, Quadriceps strength and endurance in fibrotic idiopathic interstitial pneumonia, RESPIROLOGY, Vol: 19, Pages: 138-143, ISSN: 1323-7799

Journal article

Donaldson A, Natanek SA, Lewis A, Man WD-C, Hopkinson NS, Polkey MI, Kemp PRet al., 2013, Increased skeletal muscle-specific microRNA in the blood of patients with COPD, THORAX, Vol: 68, Pages: 1140-1149, ISSN: 0040-6376

Journal article

Patel MS, Donaldson AV, Natanek SA, Bruijnzeel PLB, Hopkinson NS, Man WD-C, Kemp PR, Polkey MIet al., 2013, KLOTHO IS ASSOCIATED WITH SKELETAL MUSCLE DYSFUNCTION AND OXIDATIVE STRESS IN COPD, Winter Meeting of the British-Thoracic-Society, Publisher: BMJ PUBLISHING GROUP, Pages: A28-A29, ISSN: 0040-6376

Conference paper

Natanek SA, Gosker HR, Slot IGM, Marsh GS, Hopkinson NS, Man WD-C, Tal-Singer R, Moxham J, Kemp PR, Schols AMWJ, Polkey MIet al., 2013, HETEROGENEITY OF QUADRICEPS MUSCLE PHENOTYPE IN CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD); IMPLICATIONS FOR STRATIFIED MEDICINE?, MUSCLE & NERVE, Vol: 48, Pages: 488-497, ISSN: 0148-639X

Journal article

Lazaar AL, Miller BE, Francombe G, Duvoix A, Natanek SA, Polkey MIet al., 2013, No TWEAK for COPD, EUROPEAN RESPIRATORY JOURNAL, Vol: 42, Pages: 1142-1144, ISSN: 0903-1936

Journal article

Patel MS, Lewis A, Natanek SA, Martolini D, Bruijnzeel P, Anikin V, McGonigle N, Jordan S, Hopkinson NS, Man WD-C, Kemp P, Polkey MIet al., 2013, Klotho expression is reduced in COPD, EUROPEAN RESPIRATORY JOURNAL, Vol: 42, ISSN: 0903-1936

Journal article

Natanek SA, Riddoch-Contreras J, Marsh GS, Hopkinson NS, Moxham J, Man WD-C, Kemp PR, Polkey MIet al., 2013, MuRF-1 and Atrogin-1 Protein Expression and Quadriceps Fiber Size and Muscle Mass in Stable Patients with COPD, Copd-Journal of Chronic Obstructive Pulmonary Disease, Vol: 10, Pages: 618-624, ISSN: 1541-2563

Journal article

Hopkinson NS, Shrikrishna D, Tanner RJ, Lee JY, Natanek SA, Lewis A, Murphy PB, Hart N, Moxham J, Montgomery H, Kemp P, Polkey MIet al., 2013, The Effect Of Angiotensin-Converting Enzyme Inhibition On Skeletal Muscle Dysfunction In Chronic Obstructive Pulmonary Disease: A Randomized Controlled Trial, AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE, Vol: 187, ISSN: 1073-449X

Journal article

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