Kevin Ashton

Kevin Ashton


Research Focus & Metrics

Academic Career Length

29Years (1998-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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28 May 2011 in Journal of Translational Medicine
Verified
Journal Article
Open access
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EBEkua W Brenu
Ekua W Brenu
MDMieke L van Driel
Mieke L van Driel
DSDon R Staines
Don R Staines
KAKevin Ashton
Kevin Ashton
SRSandra B Ramos
Sandra B Ramos
SMSonya M Marshall-Gradisnik
Sonya M Marshall-Gradisnik
Background: Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME) is characterised by severe prolonged fatigue, and decreases in cognition and other physiological functions, resulting in severe loss of quality of life, difficult clinical management and high costs to the health care system. To date there is no proven pathomechanism to satisfactorily explain this disorder. Studies have identified abnormalities in immune function but these data are inconsistent. We investigated the profile of markers of immune function (including novel markers) in CFS/ME patients.Methods: We included 95 CFS/ME patients and 50 healthy controls. All participants were assessed on natural killer (NK) and CD8+T cell cytotoxic activities, Th1 and Th2 cytokine profile of CD4+T cells, expression of vasoactive intestinal peptide receptor 2 (VPACR2), levels of NK phenotypes (CD56brightand CD56dim) and regulatory T cells expressing FoxP3 transcription factor.Results: Compared to healthy individuals, CFS/ME patients displayed significant increases in IL-10, IFN-γ, TNF-α, CD4+CD25+T cells, FoxP3 and VPACR2 expression. Cytotoxic activity of NK and CD8+T cells and NK phenotypes, in particular the CD56brightNK cells were significantly decreased in CFS/ME patients. Additionally granzyme A and granzyme K expression were reduced while expression levels of perforin were significantly increased in the CFS/ME population relative to the control population. These data suggest significant dysregulation of the immune system in CFS/ME patients.Conclusions: Our study found immunological abnormalities which may serve as biomarkers in CFS/ME patients with potential for an application as a diagnostic tool.

1 October 2013 in Pharmacology & Therapeutics
Verified
Journal Article
Closed access
JHJohn Headrick
John Headrick
KAKevin Ashton
Kevin Ashton
RRRoselyn B. Rose'MEyer
Roselyn B. Rose'MEyer
JPJason N. Peart
Jason N. Peart

1 January 2020 in NeuroImage: Clinical
Verified
Journal Article
Open access
KBKathryn M. Broadhouse
Kathryn M. Broadhouse
MSMaria Fiatarone Singh
Maria Fiatarone Singh
CSChao Suo
Chao Suo
NGNicola Gates
Nicola Gates
WWWei Wen
Wei Wen
MVMichael J. Valenzuela
Michael J. Valenzuela
Dementia affects 47 million individuals worldwide, and assuming the status quo is projected to rise to 150 million by 2050. Prevention of age-related cognitive impairment in older persons with lifestyle interventions continues to garner evidence but whether this can combat underlying neurodegeneration is unknown. The Study of Mental Activity and Resistance Training (SMART) trial has previously reported within-training findings; the aim of this study was to investigate the long-term neurostructural and cognitive impact of resistance exercise in Mild Cognitive Impairment (MCI). For the first time we show that hippocampal subareas particularly susceptible to volume loss in Alzheimer's disease (AD) are protected by resistance exercise for up to one year after training. One hundred MCI participants were randomised to one of four training groups: (1) Combined high intensity progressive resistance and computerised cognitive training (PRT+CCT), (2) PRT+Sham CCT, (3) CCT+Sham PRT, (4) Sham physical+sham cognitive training (SHAM+SHAM). Physical, neuropsychological and MRI assessments were carried out at baseline, 6 months (directly after training) and 18 months from baseline (12 months after intervention cessation). Here we report neuro-structural and functional changes over the 18-month trial period and the association with global cognitive and executive function measures. PRT but not CCT or PRT+CCT led to global long-term cognitive improvements above SHAM intervention at 18-month follow-up. Furthermore, hippocampal subfields susceptible to atrophy in AD were protected by PRT revealing an elimination of long-term atrophy in the left subiculum, and attenuation of atrophy in left CA1 and dentate gyrus when compared to SHAM+SHAM (p = 0.023, p = 0.020 and p = 0.027). These neuroprotective effects mediated a significant portion of long-term cognitive benefits. By contrast, within-training posterior cingulate plasticity decayed after training cessation and was unrelated to long term cognitive benefits. Neither general physical activity levels nor fitness change over the 18-month period mediated hippocampal trajectory, demonstrating that enduring hippocampal subfield plasticity is not a simple reflection of post-training changes in fitness or physical activity participation. Notably, resting-state fMRI analysis revealed that both the hippocampus and posterior cingulate participate in a functional network that continued to be upregulated following intervention cessation. Multiple structural mechanisms may contribute to the long-term global cognitive benefit of resistance exercise, developing along different time courses but functionally linked. For the first time we show that 6 months of high intensity resistance exercise is capable of not only promoting better cognition in those with MCI, but also protecting AD-vulnerable hippocampal subfields from degeneration for at least 12 months post-intervention. These findings emphasise the therapeutic potential of resistance exercise; however, future work will need to establish just how long-lived these outcomes are and whether they are sufficient to delay dementia.

17 February 2020 in Journal of Cachexia, Sarcopenia and Muscle
Verified
Journal Article
Open access
PDF file
SVSarah Voisin
Sarah Voisin
NHNicholas R. Harvey
Nicholas R. Harvey
Larisa M. HauptLarisa M. Haupt
Larisa M. Haupt
LGLyn Griffiths
Lyn Griffiths
KAKevin Ashton
Kevin Ashton
NENir Eynon
Nir Eynon
Background: Ageing is associated with DNA methylation changes in all human tissues, and epigenetic markers can estimate chronological age based on DNA methylation patterns across tissues. However, the construction of the original pan‐tissue epigenetic clock did not include skeletal muscle samples and hence exhibited a strong deviation between DNA methylation and chronological age in this tissue.Methods: To address this, we developed a more accurate, muscle‐specific epigenetic clock based on the genome‐wide DNA methylation data of 682 skeletal muscle samples from 12 independent datasets (18–89 years old, 22% women, 99% Caucasian), all generated with Illumina HumanMethylation (HM) arrays (HM27, HM450, or HMEPIC). We also took advantage of the large number of samples to conduct an epigenome‐wide association study of age‐associated DNA methylation patterns in skeletal muscle.Results: The newly developed clock uses 200 cytosine‐phosphate–guanine dinucleotides to estimate chronological age in skeletal muscle, 16 of which are in common with the 353 cytosine‐phosphate–guanine dinucleotides of the pan‐tissue clock. The muscle clock outperformed the pan‐tissue clock, with a median error of only 4.6 years across datasets (vs. 13.1 years for the pan‐tissue clock, P < 0.0001) and an average correlation of ρ = 0.62 between actual and predicted age across datasets (vs. ρ = 0.51 for the pan‐tissue clock). Lastly, we identified 180 differentially methylated regions with age in skeletal muscle at a false discovery rate < 0.005. However, gene set enrichment analysis did not reveal any enrichment for gene ontologies.Conclusions: We have developed a muscle‐specific epigenetic clock that predicts age with better accuracy than the pan‐tissue clock. We implemented the muscle clock in an r package called Muscle Epigenetic Age Test available on Bioconductor to estimate epigenetic age in skeletal muscle samples. This clock may prove valuable in assessing the impact of environmental factors, such as exercise and diet, on muscle‐specific biological ageing processes.

1 November 2003 in American Journal of Physiology-Heart and Circulatory Physiology
Verified
Journal Article
Closed access
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JHJohn Headrick
John Headrick
BHBen Hack
Ben Hack
KAKevin Ashton
Kevin Ashton
Cells of the cardiovascular system generate and release purine nucleoside adenosine in increasing quantities when constituent cells are “stressed” or subjected to injurious stimuli. This increased adenosine can interact with surface receptors in myocardial, vascular, fibroblast, and inflammatory cells to modulate cellular function and phenotype. Additionally, adenosine is rapidly reincorporated back into 5′-AMP to maintain the adenine nucleotide pool. Via these receptor-dependent and independent (metabolic) paths, adenosine can substantially modify the acute response to ischemic insult, in addition to generating a more sustained ischemia-tolerant phenotype (preconditioning). However, the molecular basis for acute adenosinergic cardioprotection remains incompletely understood and may well differ from more widely studied preconditioning. Here we review current knowledge and some controversies regarding acute cardioprotection via adenosine and adenosine receptor activation.

14 November 2017 in BMC Genomics
Verified
Journal Article
Open access
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CWCamilla J. Williams
Camilla J. Williams
MWMark G. Williams
Mark G. Williams
NENir Eynon
Nir Eynon
KAKevin Ashton
Kevin Ashton
JLJonathan Little
Jonathan Little
JCJeff S. Coombes
Jeff S. Coombes
Cardiorespiratory fitness (VO2max) is an excellent predictor of chronic disease morbidity and mortality risk. Guidelines recommend individuals undertake exercise training to improve VO2max for chronic disease reduction. However, there are large inter-individual differences between exercise training responses. This systematic review is aimed at identifying genetic variants that are associated with VO2max trainability. Peer-reviewed research papers published up until October 2016 from four databases were examined. Articles were included if they examined genetic variants, incorporated a supervised aerobic exercise intervention; and measured VO2max/VO2peak pre and post-intervention. Thirty-five articles describing 15 cohorts met the criteria for inclusion. The majority of studies used a cross-sectional retrospective design. Thirty-two studies researched candidate genes, two used Genome-Wide Association Studies (GWAS), and one examined mRNA gene expression data, in addition to a GWAS. Across these studies, 97 genes to predict VO2max trainability were identified. Studies found phenotype to be dependent on several of these genotypes/variants, with higher responders to exercise training having more positive response alleles than lower responders (greater gene predictor score). Only 13 genetic variants were reproduced by more than two authors. Several other limitations were noted throughout these studies, including the robustness of significance for identified variants, small sample sizes, limited cohorts focused primarily on Caucasian populations, and minimal baseline data. These factors, along with differences in exercise training programs, diet and other environmental gene expression mediators, likely influence the ideal traits for VO2max trainability. Ninety-seven genes have been identified as possible predictors of VO2max trainability. To verify the strength of these findings and to identify if there are more genetic variants and/or mediators, further tightly-controlled studies that measure a range of biomarkers across ethnicities are required.