Publications by authors named "Joanne E Mallinson"

7 Publications

  • Page 1 of 1

Longitudinal hypertrophic and transcriptional responses to high-load eccentric-concentric vs concentric training in males.

Scand J Med Sci Sports 2020 Nov 26;30(11):2101-2115. Epub 2020 Aug 26.

School of Life Sciences, University of Nottingham, Nottingham, UK.

High-load eccentric training reputedly produces greater muscle hypertrophy than concentric training, possibly due to greater loading and/or inflammation. We quantified the temporal impact of combined maximal concentric-eccentric training vs maximal concentric training on muscle cross-sectional area (CSA), volume, and targeted mRNA expression (93 transcripts). Eight recreationally active males (24 ± 5 years, BMI 23.5 ± 2.5 kg/m ) performed 3 x 30 maximal eccentric isokinetic knee extensions and 2 x 30 maximal concentric knee extensions in dominant limb (ECC + CON) and 5 x 30 maximal concentric contractions (CON) in the non-dominant limb for 12 weeks (all 90°/s, 3x/wk). Quadriceps muscle CSA and volume were measured at baseline, 28 days (d), and 84 d in both limbs (3T MRI). Resting vastus lateralis biopsies were obtained from both limbs at baseline, 24 hours (h), 7, 28, and 84 d for mRNA abundance measurements (RT-PCR microfluidic cards). Work output was greater throughout training in ECC + CON vs CON (20.8 ± 9.7%, P < .001). Muscle CSA increased from baseline in both limbs at 28 d (CON 4.3 ± 2.6%, ECC + CON 4.0 ± 1.9%, both P < .001) and 84d (CON 3.9 ± 2.3%, ECC + CON 4.0 ± 3.1%, both P < .001), and muscle volume and isometric strength at 84 d (CON 44.8 ± 40.0%, P < .001; ECC + CON 36.9 ± 40.0%, P < .01), but no between-limb differences existed in any parameter. Ingenuity Pathway Analysis identified several cellular functions associated with regulation of muscle mass and metabolism as altered by both modalities at 24 h and 7 d, but particularly with ECC + CON. However, mRNA responses waned thereafter, regardless of modality. Initial muscle mRNA responses to training did not reflect chronic training-induced hypertrophy. Moreover, ECC + CON did not produce greater hypertrophy than CON, despite greater loading throughout and a differential mRNA response during the initial training week.
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http://dx.doi.org/10.1111/sms.13791DOI Listing
November 2020

Obesity Appears to Be Associated With Altered Muscle Protein Synthetic and Breakdown Responses to Increased Nutrient Delivery in Older Men, but Not Reduced Muscle Mass or Contractile Function.

Diabetes 2015 Sep 26;64(9):3160-71. Epub 2015 May 26.

MRC Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, U.K.

Obesity is increasing, yet despite the necessity of maintaining muscle mass and function with age, the effect of obesity on muscle protein turnover in older adults remains unknown. Eleven obese (BMI 31.9 ± 1.1 kg · m(-2)) and 15 healthy-weight (BMI 23.4 ± 0.3 kg · m(-2)) older men (55-75 years old) participated in a study that determined muscle protein synthesis (MPS) and leg protein breakdown (LPB) under postabsorptive (hypoinsulinemic-euglycemic clamp) and postprandial (hyperinsulinemic hyperaminoacidemic-euglycemic clamp) conditions. Obesity was associated with systemic inflammation, greater leg fat mass, and patterns of mRNA expression consistent with muscle deconditioning, whereas leg lean mass, strength, and work done during maximal exercise were no different. Under postabsorptive conditions, MPS and LPB were equivalent between groups, whereas insulin and amino acid administration increased MPS in only healthy-weight subjects and was associated with lower leg glucose disposal (LGD) (63%) in obese men. Blunting of MPS in the obese men was offset by an apparent decline in LPB, which was absent in healthy-weight subjects. Lower postprandial LGD in obese subjects and blunting of MPS responses to amino acids suggest that obesity in older adults is associated with diminished muscle metabolic quality. This does not, however, appear to be associated with lower leg lean mass or strength.
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http://dx.doi.org/10.2337/db15-0021DOI Listing
September 2015

Statin myalgia is not associated with reduced muscle strength, mass or protein turnover in older male volunteers, but is allied with a slowing of time to peak power output, insulin resistance and differential muscle mRNA expression.

J Physiol 2015 Mar 26;593(5):1239-57. Epub 2015 Jan 26.

MRC/Arthritis Research UK Centre for Musculoskeletal Ageing Research, University of Nottingham, Nottingham, NG7 2UH, UK.

Statins are associated with muscle myalgia and myopathy, which probably reduce habitual physical activity. This is particularly relevant to older people who are less active, sarcopaenic and at increased risk of statin myalgia. We hypothesised that statin myalgia would be allied to impaired strength and work capacity in older people, and determined whether differences aligned with divergences in lean mass, protein turnover, insulin sensitivity and the molecular regulation of these processes. Knee extensor strength and work output during 30 maximal isokinetic contractions were assessed in healthy male volunteers, nine with no statin use (control 70.4 ± 0.7 years) and nine with statin myalgia (71.5 ± 0.9 years). Whole body and leg glucose disposal, muscle myofibrillar protein synthesis (MPS) and leg protein breakdown (LPB) were measured during fasting (≈5 mU l(-1) insulin) and fed (≈40 mU l(-1) insulin + hyperaminoacidaemia) euglyceamic clamps. Muscle biopsies were taken before and after each clamp. Lean mass, MPS, LPB and strength were not different but work output during the initial three isokinetic contractions was 19% lower (P < 0.05) in statin myalgic subjects due to a delay in time to reach peak power output. Statin myalgic subjects had reduced whole body (P = 0.05) and leg (P < 0.01) glucose disposal, greater abdominal adiposity (P < 0.05) and differential expression of 33 muscle mRNAs (5% false discovery rate (FDR)), six of which, linked to mitochondrial dysfunction and apoptosis, increased at 1% FDR. Statin myalgia was associated with impaired muscle function, increased abdominal adiposity, whole body and leg insulin resistance, and evidence of mitochondrial dysfunction and apoptosis.
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http://dx.doi.org/10.1113/jphysiol.2014.285577DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4358682PMC
March 2015

Pharmacological activation of the pyruvate dehydrogenase complex reduces statin-mediated upregulation of FOXO gene targets and protects against statin myopathy in rodents.

J Physiol 2012 Dec 8;590(24):6389-402. Epub 2012 Oct 8.

MRC/Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Biomedical Sciences, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK.

We previously reported that statin myopathy is associated with impaired carbohydrate (CHO) oxidation in fast-twitch rodent skeletal muscle, which we hypothesised occurred as a result of forkhead box protein O1 (FOXO1) mediated upregulation of pyruvate dehydrogenase kinase-4 (PDK4) gene transcription. Upregulation of FOXO gene targets known to regulate proteasomal and lysosomal muscle protein breakdown was also evident. We hypothesised that increasing CHO oxidation in vivo, using the pyruvate dehydrogenase complex (PDC) activator, dichloroacetate (DCA), would blunt activation of FOXO gene targets and reduce statin myopathy. Female Wistar Hanover rats were dosed daily for 12 days (oral gavage) with either vehicle (control, 0.5% w/v hydroxypropyl-methylcellulose 0.1% w/v polysorbate-80; n = 9), 88 mg( )kg(-1) day(-1) simvastatin (n = 8), 88 mg( )kg(-1) day(-1) simvastatin + 30 mg kg(-1) day(-1) DCA (n = 9) or 88 mg kg(-1) day(-1) simvastatin + 40 mg kg(-1) day(-1) DCA (n = 9). Compared with control, simvastatin reduced body mass gain and food intake, increased muscle fibre necrosis, plasma creatine kinase levels, muscle PDK4, muscle atrophy F-box (MAFbx) and cathepsin-L mRNA expression, increased PDK4 protein expression, and proteasome and cathepsin-L activity, and reduced muscle PDC activity. Simvastatin with DCA maintained body mass gain and food intake, abrogated the myopathy, decreased muscle PDK4 mRNA and protein, MAFbx and cathepsin-L mRNA, increased activity of PDC and reduced proteasome activity compared with simvastatin. PDC activation abolished statin myopathy in rodent skeletal muscle, which occurred at least in part via inhibition of FOXO-mediated transcription of genes regulating muscle CHO utilisation and protein breakdown.
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http://dx.doi.org/10.1113/jphysiol.2012.238022DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3533200PMC
December 2012

Mechanisms responsible for disuse muscle atrophy: potential role of protein provision and exercise as countermeasures.

Nutrition 2013 Jan 28;29(1):22-8. Epub 2012 Aug 28.

Metabolic Physiology, The School of Biomedical Sciences, The University of Nottingham Medical School, Queen's Medical Centre, Nottingham, United Kingdom.

Muscle disuse is often observed after injury or during periods of illness, resulting in the loss of muscle mass and strength, with sometimes debilitating consequences. Although substantial advancements have been made in determining the mechanisms responsible for the etiology of muscle disuse atrophy in rodents, only in recent years have studies of any significant number focused on reaffirming these findings in humans. In this review, we discuss the processes responsible for disuse atrophy as based on current evidence and highlight where gaps in our knowledge persist. Furthermore, given the emphasis placed on resistance exercise and nutrition as potential therapeutic countermeasures, we consider recent advancements in the study of resistance exercise and nutrition in the stimulation of muscle protein synthesis and the associated implications when devising effective treatment strategies.
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http://dx.doi.org/10.1016/j.nut.2012.04.012DOI Listing
January 2013

Blunted Akt/FOXO signalling and activation of genes controlling atrophy and fuel use in statin myopathy.

J Physiol 2009 Jan 10;587(1):219-30. Epub 2008 Nov 10.

Centre for Integrated Systems Biology and Medicine, School of Biomedical Sciences, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK.

Statins are used clinically for cholesterol reduction, but statin therapy is associated with myopathic changes through a poorly defined mechanism. We used an in vivo model of statin myopathy to determine whether statins up-regulate genes associated with proteasomal- and lysosomal-mediated proteolysis and whether PDK gene expression is simultaneously up-regulated leading to the impairment of muscle carbohydrate oxidation. Animals were dosed daily with 80 mg kg(-1) day(-1) simvastatin for 4 (n = 6) and 12 days (n = 5), 88 mg kg(-1) day(-1) simvastatin for 12 days (n = 4), or vehicle (0.5% w/v hydroxypropyl-methylcellulose and 0.1% w/v polysorbate 80; Control, n = 6) for 12 days by oral gavage. We found, in biceps femoris muscle, decreased Akt(Ser473), FOXO1(Ser253) and FOXO3a(Ser253) phosphorylation in the cytosol (P < 0.05, P < 0.05, P < 0.001, respectively) and decreased phosphorylation of FOXO1 in the nucleus after 12 days simvastatin when compared to Control (P < 0.05). This was paralleled by a marked increase in the transcription of downstream targets of FOXO, i.e. MAFbx (P < 0.001), MuRF-1 (P < 0.001), cathepsin-L (P < 0.05), PDK2 (P < 0.05) and PDK4 (P < 0.05). These changes were accompanied by increased PPARalpha (P < 0.05), TNFalpha (P < 0.01), IL6 (P < 0.01), Mt1A (P < 0.01) mRNA and increased muscle glycogen (P < 0.05) compared to Control. RhoA activity decreased after 4 days simvastatin (P < 0.05); however, activity was no different from Control after 12 days. Simvastatin down-regulated PI3k/Akt signalling, independently of RhoA, and up-regulated FOXO transcription factors and downstream gene targets known to be implicated in proteasomal- and lysosomal-mediated muscle proteolysis, carbohydrate oxidation, oxidative stress and inflammation in an in vivo model of statin-induced myopathy. These changes occurred in the main before evidence of extensive myopathy or a decline in the muscle protein to DNA ratio.
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http://dx.doi.org/10.1113/jphysiol.2008.164699DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2670035PMC
January 2009

Fetal exposure to a maternal low-protein diet during mid-gestation results in muscle-specific effects on fibre type composition in young rats.

Br J Nutr 2007 Aug 29;98(2):292-9. Epub 2007 Mar 29.

Division of Nutritional Sciences, School of Biosciences, University of Nottingham, Sutton Bonington, Loughborough, LE12 5RD, UK.

This study assessed the impact of reduced dietary protein during specific periods of fetal life upon muscle fibre development in young rats. Pregnant rats were fed a control or low-protein (LP) diet at early (days 0-7 gestation, LPEarly), mid (days 8-14, LPMid), late (days 15-22, LPLate) or throughout gestation (days 0-22, LPAll). The muscle fibre number and composition in soleus and gastrocnemius muscles of the offspring were studied at 4 weeks of age. In the soleus muscle, both the total number and density of fast fibres were reduced in LPMid females (P = 0.004 for both, Diet x Sex x Fibre type interactions), while both the total number and density of glycolytic (non-oxidative) fibres were reduced in LPEarly, LPMid and LPLate (but not LPAll) offspring compared with controls (P < 0.001 for both, Diet x Fibre type interaction). In the gastrocnemius muscle, only the density of oxidative fibres was reduced in LPMid compared with control offspring (P = 0.019, Diet x Fibre type interaction), with the density of slow fibres being increased in LPAll males compared with control (P = 0.024, Diet x Sex x Fibre type interaction). There were little or no effects of maternal diet on fibre type diameters in the two muscles. In conclusion, a maternal low-protein diet mainly during mid-pregnancy reduced muscle fibre number and density in 4-week-old rats, but there were muscle-specific differences in the fibre types affected.
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http://dx.doi.org/10.1017/S0007114507701678DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3861786PMC
August 2007
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