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McCormick KG, Scorletti E, Bhatia L, Calder PC, Griffin MJ, Clough GF, Byrne CD. Impact of high dose n-3 polyunsaturated fatty acid treatment on measures of microvascular function and vibration perception in non-alcoholic fatty liver disease: results from the randomised WELCOME trial. Diabetologia 2015; 58:1916-25. [PMID: 26021488 DOI: 10.1007/s00125-015-3628-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 04/29/2015] [Indexed: 12/20/2022]
Abstract
AIMS/HYPOTHESIS The effect of n-3 fatty acid treatment on vibration perception thresholds (VPTs) and cutaneous microvascular reactivity is not known. We tested whether: (1) a 15-18 month treatment with high dose (4 g/day) docosahexaenoic (DHA) plus eicosapentaenoic (EPA) acid improved VPT and microvascular reactivity in patients with non-alcoholic fatty liver disease; and (2) there are associations between VPT, microvascular reactivity and metabolic variables. METHODS In the completed single centre, randomised, parallel group, placebo controlled Wessex Evaluation of fatty Liver and Cardiovascular markers in non-alcoholic fatty liver disease with OMacor thErapy (WELCOME) trial, we tested the effect of DHA+EPA on VPT at 125 Hz (big toe) and the cutaneous hyperaemic response (forearm) to arterial occlusion (ratio of maximum to resting blood flux [MF/RF]). Allocation and dispensing was carried out by an independent research pharmacist; all participants and research team members were blinded to group assignment. RESULTS In all, 51 and 49 patients were randomised to placebo and DHA+EPA, respectively (mean age 51.4 years). Of these, 32 had type 2 diabetes. Forty-six (placebo) and 47 (DHA+EPA) patients completed the study; there were no important adverse (or unexpected) effects or side effects. In multivariable-adjusted regression models (intention-to-treat analyses), DHA+EPA treatment was associated with an increase in VPT (β coefficient 1.49 [95% CI 0.04, 2.94], p = 0.04). For VPT, the adjusted mean differences (95% CIs) in the placebo and DHA+EPA treatment groups were -0.725 (-1.71, 0.25) and 0.767 (-0.21, 1.75) m/s(2), respectively. With DHA+EPA treatment, there was no change in MF/RF (β coefficient 0.07 [95% CI -0.56, 0.70], p = 0.84), the adjusted mean differences (95% CIs) in the placebo and DHA+EPA treatment groups were -0.549 (-1.03, -0.07) and -0.295 (-0.77, 0.18) respectively. VPT was independently associated with age (β coefficient 0.019 [95% CI 0.010, 0.029], p < 0.0001) and MF/RF (β coefficient -0.074 [95% CI -0.132, -0.016], p = 0.013), but not with diabetes (p = 0.38). CONCLUSIONS/INTERPRETATION High dose n-3 fatty acid treatment did not improve measures of microvascular function or vibration perception. Ageing and microvascular reactivity are associated with a measure of peripheral nerve function. TRIAL REGISTRATION ClinicalTrials.gov NCT00760513. FUNDING The study was funded by the National Institute for Health Research UK and Diabetes UK.
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Pontes IEA, Afra KF, Silva JR, Borges PSN, Clough GF, Alves JGB. Microvascular reactivity in women with gestational diabetes mellitus studied during pregnancy. Diabetol Metab Syndr 2015; 7:27. [PMID: 26056535 PMCID: PMC4459465 DOI: 10.1186/s13098-015-0017-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Accepted: 03/03/2015] [Indexed: 01/11/2023] Open
Abstract
AIM To compare microvascular reactivity assessed in the skin using laser Doppler fluximetry (LDF) in women with gestational diabetes mellitus (GDM) and gestational age-matched control during pregnancy. METHODS 110 pregnant women at ~33 weeks gestation participated in the study. Skin microvascular reactivity was evaluated by LDF, at rest, during the response to brief arterial occlusion (post occlusive hyperaemic response) and during sympathetically mediated vasoconstrictor response to deep inspiratory breath hold. RESULTS No statistically significant differences were found in the microvascular variables studied (resting and maximum rate flux, post-ischaemic reactive hyperaemia and deep inspiratory breath holds) between +GDM and -GDM groups women. In women with GDM there was a negative correlation between resting flux and the response to the oral glucose tolerance test (OGTT), r = -0.282 (p = 0.037). There was also a negative correlation between the response to the OGTT and the sympathetically mediated constrictor response to inspiratory breath holds (r = -.298, p = .030) but not in women with GDM (r = .102, r = .468). CONCLUSION Attenuated microvascular reactivity as an early marker of endothelial dysfunction is not present in women with GDM when assessed during pregnancy.
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Scorletti E, Bhatia L, McCormick KG, Clough GF, Nash K, Hodson L, Moyses HE, Calder PC, Byrne CD. Effects of purified eicosapentaenoic and docosahexaenoic acids in nonalcoholic fatty liver disease: results from the Welcome* study. Hepatology 2014; 60:1211-21. [PMID: 25043514 DOI: 10.1002/hep.27289] [Citation(s) in RCA: 231] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 06/05/2014] [Accepted: 06/21/2014] [Indexed: 02/06/2023]
Abstract
There is no licensed treatment for non-alcoholic fatty liver disease (NAFLD), a condition that increases risk of chronic liver disease, type 2 diabetes and cardiovascular disease. We tested whether 15-18 months treatment with docosahexaenoic acid (DHA) plus eicosapentaenoic acid (EPA) (Omacor/Lovaza) (4 g/day) decreased liver fat and improved two histologically-validated liver fibrosis biomarker scores (primary outcomes). Patients with NAFLD were randomised in a double blind placebo-controlled trial [DHA+EPA(n=51), placebo(n=52)]. We quantified liver fat percentage (%) by magnetic resonance spectroscopy in three liver zones. We measured liver fibrosis using two validated scores. We tested adherence to the intervention (Omacor group) and contamination (with DHA and EPA) (placebo group) by measuring erythrocyte percentage DHA and EPA enrichment (gas chromatography). We undertook multivariable linear regression to test effects of: a) DHA+EPA treatment (ITT analyses) and b) erythrocyte DHA and EPA enrichment (secondary analysis). Median (IQR) baseline and end of study liver fat% were 21.7 (19.3) and 19.7 (18.0) (placebo), and 23.0 (36.2) and 16.3 (22.0), (DHA+EPA). In the fully adjusted regression model there was a trend towards improvement in liver fat% with DHA+EPA treatment (β=-3.64 (95%CI -8.0,0.8); p=0.1) but there was evidence of contamination in the placebo group and variable adherence to the intervention in the Omacor group. Further regression analysis showed that DHA enrichment was independently associated with a decrease in liver fat% (for each 1% enrichment, β=-1.70 (95%CI -2.9,-0.5); p=0.007). No improvement in the fibrosis scores occurred. Conclusion. Erythrocyte DHA enrichment with DHA+EPA treatment is linearly associated with decreased liver fat%. Substantial decreases in liver fat% can be achieved with high percentage erythrocyte DHA enrichment in NAFLD. (Hepatology 2014;).
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Kuliga KZ, McDonald EF, Gush R, Michel C, Chipperfield AJ, Clough GF. Dynamics of Microvascular Blood Flow and Oxygenation Measured Simultaneously in Human Skin. Microcirculation 2014; 21:562-73. [DOI: 10.1111/micc.12136] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 03/27/2014] [Indexed: 12/24/2022]
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Valletta JJ, Chipperfield AJ, Clough GF, Byrne CD. Daily energy expenditure, cardiorespiratory fitness and glycaemic control in people with type 1 diabetes. PLoS One 2014; 9:e97534. [PMID: 24826899 PMCID: PMC4020853 DOI: 10.1371/journal.pone.0097534] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 04/21/2014] [Indexed: 12/20/2022] Open
Abstract
Objective Encouraging daily physical activity improves cardiorespiratory fitness and many cardiovascular risk factors. However, increasing physical activity often creates a challenge for people with type 1 diabetes, because of difficulties maintaining euglycemia in the face of altered food intake and adjustments to insulin doses. Our aim was to examine the triangular relationship between glucose control measured by continuous glucose monitoring system (CGMS), objective measures of total daily energy expenditure (TEE) recorded by a multi-sensory monitoring device, and cardiorespiratory fitness (CRF), in free-living subjects with type 1 diabetes. Research Design and Methods Twenty-three individuals (12 women) with type 1 diabetes who were free from micro- and macrovascular complications were recruited. TEE and glucose control were monitored simultaneously for up to 12 days, using a multi-sensory device and CGMS respectively. CRF was recorded as V02 max from a maximal treadmill test with the Bruce protocol. Results Subjects (mean±SD) were aged 37±11 years, with BMI = 26.5±5.1 kg.m−2, HbA1c = 7.7±1.3% (61±14 mmol/mol) and V02 max (ml.min−1.kg−1) = 39.9±8.4 (range 22.4 – 58.6). TEE (36.3±5.5 kcal.kg−1.day−1) was strongly associated with CRF(39.9±8.4 ml.min−1.kg−1) independently of sex (r = 0.63, p<0.01). However, neither TEE (r = −0.20, p = 0.36) nor CRF (r = −0.20, p = 0.39; adjusted for sex), were significantly associated with mean glycaemia measured by CGMS. Conclusion Higher levels of energy expenditure (due to a more active lifestyle) are associated with increased cardiorespiratory fitness, but not necessarily better glycaemic control. Since increased levels of energy expenditure and good glycaemic control are both needed to protect against diabetes-related complications our data suggest they need to be achieved independently.
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Scorletti E, Bhatia L, McCormick KG, Clough GF, Nash K, Calder PC, Byrne CD. Design and rationale of the WELCOME trial: A randomised, placebo controlled study to test the efficacy of purified long chainomega-3 fatty acid treatment in non-alcoholic fatty liver disease [corrected]. Contemp Clin Trials 2014; 37:301-11. [PMID: 24556343 DOI: 10.1016/j.cct.2014.02.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 01/28/2014] [Accepted: 02/05/2014] [Indexed: 02/06/2023]
Abstract
BACKGROUND Non-alcoholic fatty liver disease (NAFLD) represents a range of liver conditions from simple fatty liver to progressive end stage liver disease requiring liver transplantation. NAFLD is common in the population and in certain sub groups (e.g. type 2 diabetes) up to 70% of patients may be affected. NAFLD is not only a cause of end stage liver disease and hepatocellular carcinoma, but is also an independent risk factor for type 2 diabetes and cardiovascular disease. Consequently, effective treatments for NAFLD are urgently needed. OBJECTIVES The WELCOME study is testing the hypothesis that treatment with high dose purified long chain omega-3 fatty acids will have a beneficial effect on a) liver fat percentage and b) two histologically validated algorithmically-derived biomarker scores for liver fibrosis. DESIGN In a randomised double blind placebo controlled trial, 103 participants with NAFLD were randomised to 15-18months treatment with either 4g/day purified long chain omega-3 fatty acids (Omacor) or 4g/day olive oil as placebo. Erythrocyte percentage DHA and EPA enrichment (a validated proxy for hepatic enrichment) was determined by gas chromatography. Liver fat percentage was measured in three discrete liver zones by magnetic resonance spectroscopy (MRS). We also measured body fat distribution, physical activity and a range of cardiometabolic risk factors. METHODS Recruitment started in January 2010 and ended in June 2011. We identified 178 potential participants, and randomised 103 participants who met the inclusion criteria. The WELCOME study was approved by the local ethics committee (REC: 08/H0502/165; www.clinicalTrials.gov registration number NCT00760513).
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He D, Nguyen HC, Hayes-Gill BR, Zhu Y, Crowe JA, Gill C, Clough GF, Morgan SP. Laser doppler blood flow imaging using a CMOS imaging sensor with on-chip signal processing. SENSORS 2013; 13:12632-47. [PMID: 24051525 PMCID: PMC3821350 DOI: 10.3390/s130912632] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 09/06/2013] [Accepted: 09/09/2013] [Indexed: 11/16/2022]
Abstract
The first fully integrated 2D CMOS imaging sensor with on-chip signal processing for applications in laser Doppler blood flow (LDBF) imaging has been designed and tested. To obtain a space efficient design over 64 × 64 pixels means that standard processing electronics used off-chip cannot be implemented. Therefore the analog signal processing at each pixel is a tailored design for LDBF signals with balanced optimization for signal-to-noise ratio and silicon area. This custom made sensor offers key advantages over conventional sensors, viz. the analog signal processing at the pixel level carries out signal normalization; the AC amplification in combination with an anti-aliasing filter allows analog-to-digital conversion with a low number of bits; low resource implementation of the digital processor enables on-chip processing and the data bottleneck that exists between the detector and processing electronics has been overcome. The sensor demonstrates good agreement with simulation at each design stage. The measured optical performance of the sensor is demonstrated using modulated light signals and in vivo blood flow experiments. Images showing blood flow changes with arterial occlusion and an inflammatory response to a histamine skin-prick demonstrate that the sensor array is capable of detecting blood flow signals from tissue.
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Clough GF, Stenken JA, Church MK. High Molecular Weight Targets and Treatments Using Microdialysis. MICRODIALYSIS IN DRUG DEVELOPMENT 2013. [DOI: 10.1007/978-1-4614-4815-0_13] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Winter CD, Clough GF, Pringle AK, Church MK. Outcome following severe traumatic brain injury TBI correlates with serum S100B but not brain extracellular fluid S100B: An intracerebral microdialysis study. ACTA ACUST UNITED AC 2013. [DOI: 10.4236/wjns.2013.32013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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He D, Nguyen HC, Hayes-Gill BR, Zhu Y, Crowe JA, Clough GF, Gill CA, Morgan SP. 64×64 pixel smart sensor array for laser Doppler blood flow imaging. OPTICS LETTERS 2012; 37:3060-3062. [PMID: 22859085 DOI: 10.1364/ol.37.003060] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
What is believed to be the first fully integrated two-dimensional complementary metal oxide semiconductor (CMOS) imaging array for laser Doppler blood flow imaging is demonstrated. The sensor has 64×64 pixels and includes both analog and digital on-chip processing electronics. This offers several potential advantages over commercial sensors as the processing is tailored to the signals of interest and the data bottleneck that exists between the sensor and processing electronics is overcome. To obtain a space efficient design over 64×64 pixels means that standard processing electronics used off-chip cannot be implemented. Images of both simulated blood flow responses and a blood flow occlusion test demonstrate the capability.
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Siow RCM, Clough GF. Spotlight issue: MicroRNAs in the microcirculation--from cellular mechanisms to clinical markers. Microcirculation 2012; 19:193-5. [PMID: 22284132 DOI: 10.1111/j.1549-8719.2012.00166.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
This spotlight issue of Microcirculation contains four state-of-the-art review articles on the role of microRNAs (miRNAs), a class of endogenous, highly conserved, small, non-coding RNAs that regulate gene expression at the post transcriptional level, and can act as key regulators of cellular mechanisms within the microcirculation. The expert reviews address issues, such as the role of miRNAs in determining endothelial cell differentiation and lineage commitment, the physiological role of miRNAs as critical modulators of endothelial cell proliferation, apoptosis and in angiogenesis, and their aberrant expression in different vascular disorders. The reviews also explore the prognostic value of miRNAs in cardiovascular disease and how they may serve both as a therapeutic target and clinical biomarker in the future. This cutting edge edition of the journal Microcirculation highlights the progress that has been made in this new and challenging research area.
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L'Esperance VS, Cox SE, Simpson D, Gill C, Makani J, Soka D, Mgaya J, Kirkham FJ, Clough GF. Peripheral vascular response to inspiratory breath hold in paediatric homozygous sickle cell disease. Exp Physiol 2012; 98:49-56. [PMID: 22660812 PMCID: PMC4463767 DOI: 10.1113/expphysiol.2011.064055] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
New Findings • What is the central question of this study? Autonomic nervous dysfunction is implicated in complications of sickle cell anaemia (SCA). In healthy adults, a deep inspiratory breath hold (IBH) elicits rapid transient SNS- mediated vasoconstriction detectable using Laser Doppler Flux (LDF) assessment of the finger-tip cutaneous micovasculature. • What is the main finding and its importance? We demonstrate significantly increased resting peripheral blood flow and sympathetic activity in African children with SCA compared to sibling controls and increased sympathetic stimulation in response to vasoprovocation with DIG. This study is the first to observe an inverse association between resting peripheral blood flow and haemoglobin oxygen saturation (SpO2). These phenomena may be an adaptive response to the hypoxic exposure in SCA. There is increasing evidence that autonomic dysfunction in adults with homozygous sickle cell (haemoglobin SS) disease is associated with enhanced autonomic nervous system-mediated control of microvascular perfusion. However, it is unclear whether such differences are detectable in children with SS disease. We studied 65 children with SS disease [38 boys; median age 7.2 (interquartile range 5.1–10.6) years] and 20 control children without symptoms of SS disease [8 boys; 8.7 (5.5–10.8) years] and recorded mean arterial blood pressure (ABP) and daytime haemoglobin oxygen saturation (). Cutaneous blood flux at rest (RBF) and during the sympathetically activated vasoconstrictor response to inspiratory breath hold (IBH) were measured in the finger pulp of the non-dominant hand using laser Doppler fluximetry. Local factors mediating flow motion were assessed by power spectral density analysis of the oscillatory components of the laser Doppler signal. The RBF measured across the two study groups was negatively associated with age (r=−0.25, P < 0.0001), ABP (r=−0.27, P= 0.02) and daytime (r=−0.30, P= 0.005). Children with SS disease had a higher RBF (P= 0.005) and enhanced vasoconstrictor response to IBH (P= 0.002) compared with control children. In children with SS disease, higher RBF was associated with an increase in the sympathetic interval (r=−0.28, P= 0.022). The SS disease status, daytime and age explained 22% of the variance in vasoconstrictor response to IBH (P < 0.0001). Our findings suggest that blood flow and blood flow responses in the skin of young African children with SS disease differ from those of healthy control children, with increased resting peripheral blood flow and increased sympathetic stimulation from a young age in SS disease. They further suggest that the laser Doppler flowmetry technique with inspiratory breath hold manoeuvre appears to be robust for use in young children with SS disease, to explore interactions between , ABP and autonomic function with clinical complications, e.g. skin ulceration.
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Valletta JJ, Chipperfield AJ, Clough GF, Byrne CD. Metabolic regulation during constant moderate physical exertion in extreme conditions in Type 1 diabetes. Diabet Med 2012; 29:822-6. [PMID: 21916974 DOI: 10.1111/j.1464-5491.2011.03453.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Constant moderate intensity physical exertion in humid environments at altitude poses a considerable challenge to maintaining euglycaemia with Type 1 diabetes. Blood glucose concentrations and energy expenditure were continuously recorded in a person trekking at altitude in a tropical climate to quantify changes in glucose concentrations in relation to energy expenditure. CASE REPORT Blood glucose concentrations and energy expenditure were continuously monitored with a Guardian® real-time continuous glucose monitoring system (CGMS) and a SenseWear® Pro3 armband (BodyMedia Inc., USA), in a 27-year-old woman with Type 1 diabetes, during her climb up Mount Kinabalu in Borneo (c. 4095 m). Comparative control data from the same person was collected in the UK (temperate climate at sea level) and Singapore (tropical climate at sea level). Maximum physical effort during the climb was < 60% VO(2MAX) (maximal oxygen consumption). Mean daily calorific intakes were 2300 kcal (UK), 2370 kcal (Singapore) and 2274 kcal (Mount Kinabalu), and mean daily insulin doses were 54 U (UK), 40 U (Singapore) and 47 U (Mount Kinabalu). Despite markedly increased energy expenditure during the climb [4202 kcal (Mount Kinabalu) vs. 2948 kcal (UK) and 2662 kcal (Singapore)], mean blood glucose was considerably higher during the trek up Mount Kinabalu [13.2 ± 5.9 mmol/l, vs. 7.9 ± 3.8 mmol/l (UK) and 8.6 ± 4.0 mmol/l (Singapore)]. CONCLUSION Marked unexpected hyperglycaemia occurred while trekking on Mount Kinabalu, despite similar calorie consumption and insulin doses to control conditions. Because of the risk of unexpected hyperglycaemia in these conditions, we recommend that patients embarking on similar activity holidays undertake frequent blood glucose monitoring.
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Kelsall CJ, Hoile SP, Irvine NA, Masoodi M, Torrens C, Lillycrop KA, Calder PC, Clough GF, Hanson MA, Burdge GC. Vascular dysfunction induced in offspring by maternal dietary fat involves altered arterial polyunsaturated fatty acid biosynthesis. PLoS One 2012; 7:e34492. [PMID: 22509311 PMCID: PMC3317992 DOI: 10.1371/journal.pone.0034492] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Accepted: 03/01/2012] [Indexed: 12/26/2022] Open
Abstract
Nutrition during development affects risk of future cardiovascular disease. Relatively little is known about whether the amount and type of fat in the maternal diet affect vascular function in the offspring. To investigate this, pregnant and lactating rats were fed either 7%(w/w) or 21%(w/w) fat enriched in either 18:2n-6, trans fatty acids, saturated fatty acids, or fish oil. Their offspring were fed 4%(w/w) soybean oil from weaning until day 77. Type and amount of maternal dietary fat altered acetylcholine (ACh)-mediated vaso-relaxation in offspring aortae and mesenteric arteries, contingent on sex. Amount, but not type, of maternal dietary fat altered phenylephrine (Pe)-induced vasoconstriction in these arteries. Maternal 21% fat diet decreased 20:4n-6 concentration in offspring aortae. We investigated the role of Δ6 and Δ5 desaturases, showing that their inhibition in aortae and mesenteric arteries reduced vasoconstriction, but not vaso-relaxation, and the synthesis of specific pro-constriction eicosanoids. Removal of the aortic endothelium did not alter the effect of inhibition of Δ6 and Δ5 desaturases on Pe-mediated vasoconstriction. Thus arterial smooth muscle 20:4n-6 biosynthesis de novo appears to be important for Pe-mediated vasoconstriction. Next we studied genes encoding these desaturases, finding that maternal 21% fat reduced Fads2 mRNA expression and increased Fads1 in offspring aortae, indicating dysregulation of 20:4n-6 biosynthesis. Methylation at CpG -394 bp 5' to the Fads2 transcription start site predicted its expression. This locus was hypermethylated in offspring of dams fed 21% fat. Pe treatment of aortae for 10 minutes increased Fads2, but not Fads1, mRNA expression (76%; P<0.05). This suggests that Fads2 may be an immediate early gene in the response of aortae to Pe. Thus both amount and type of maternal dietary fat induce altered regulation of vascular tone in offspring though differential effects on vaso-relaxation, and persistent changes in vasoconstriction via epigenetic processes controlling arterial polyunsaturated fatty acid biosynthesis.
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MESH Headings
- Acetylcholine/pharmacology
- Adrenergic alpha-1 Receptor Agonists/pharmacology
- Animals
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/metabolism
- Aorta, Thoracic/physiopathology
- Arteries/drug effects
- Arteries/metabolism
- Arteries/physiopathology
- Delta-5 Fatty Acid Desaturase
- Dietary Fats/adverse effects
- Fatty Acids, Unsaturated/biosynthesis
- Fatty Acids, Unsaturated/blood
- Female
- Gene Expression Regulation, Enzymologic/drug effects
- Male
- Mesenteric Arteries/drug effects
- Mesenteric Arteries/metabolism
- Mesenteric Arteries/physiopathology
- Mothers
- Muscarinic Agonists/pharmacology
- Phenylephrine/pharmacology
- Pregnancy
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rats
- Rats, Wistar
- Receptors, Adrenergic, alpha-1/metabolism
- Receptors, Muscarinic/metabolism
- Stearoyl-CoA Desaturase/genetics
- Vasoconstriction/drug effects
- Vasodilation/drug effects
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Gill C, Parkinson E, Church MK, Skipp P, Scott D, White AJ, O'Connor CD, Clough GF. A qualitative and quantitative proteomic study of human microdialysate and the cutaneous response to injury. AAPS JOURNAL 2011; 13:309-17. [PMID: 21494910 DOI: 10.1208/s12248-011-9269-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Accepted: 03/07/2011] [Indexed: 01/16/2023]
Abstract
The extracellular fluid space is the site of intercellular communication and represents an important source of mediators that can shed light on the parenchymal environment. Sampling of this compartment using continuous microdialysis allows assessment of the temporal changes in extracellular mediators involved in tissue homeostasis and disease processes. However, novel biomarker identification is limited by the current need to utilize specific, targeted molecular assays. The aim of our study was to explore the use of qualitative and quantitative proteomic approaches to define the protein content of dermal dialysate. Timed dermal dialysate samples were collected from healthy human volunteers for 5 h following probe insertion, using a 3,000-kDa MWCO membrane perfused at a rate of 3 μl/min. Dialysate proteins were identified using GeLC-MS/MS and iTRAQ approaches and functions assigned according to the Gene Ontology classification system. More than 80 proteins (size range 11-516 kDa) originating from both extracellular and intracellular fluid space were identified using the qualitative approach of GeLC-MS/MS. Quantitative iTRAQ data were obtained for 27 proteins with relative change ratios between consecutive timed samples showing changes of >1.5-fold. Interstitial proteins can be identified and measured using shotgun proteomic techniques and changes detected during the acute inflammatory response. Our findings provide a platform from which to explore novel protein biomarkers and their modulation in health and disease.
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Clough GF, L'Esperance V, Turzyniecka M, Walter L, Chipperfield AJ, Gamble J, Krentz AJ, Byrne CD. Functional dilator capacity is independently associated with insulin sensitivity and age in central obesity and is not improved by high dose statin treatment. Microcirculation 2011; 18:74-84. [PMID: 21166928 DOI: 10.1111/j.1549-8719.2010.00070.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To test the hypothesis that: (i) functional microvascular dilator capacity is independently associated with insulin sensitivity and age in individuals with central adiposity at risk of cardiovascular disease (CVD); and (ii) functional microvascular dilator capacity is improved by high dose statin treatment. METHODS Functional dilator capacity (measured as change in laser Doppler blood flux from baseline during post occlusive reactive hyperemia [peak flux%resting flux; PF%RF] and flowmotion (power spectral density [PSD] analysis)) were assessed in 40 people with central adiposity and one or more other CVD risk factors. Measurements were made at rest and during acute hyperinsulinaemia before and six months after high dose atorvastatin (40 mg daily) or placebo. RESULTS Insulin-induced change in PF%RF was independently associated with insulin sensitivity (M/I) (r = 0.46 p = 0.02) and age (r = -0.46 p = 0.02), which together explained almost half of the variance in PF%RF (adjusted r² = 0.37, p = 0.008). Whilst atorvastatin decreased LDL cholesterol by 51% (p < 0.001), PF%RF and flowmotion remained unchanged. CONCLUSIONS Insulin sensitivity and age are independently associated with an insulin-induced change in functional microvascular dilator capacity in individuals with central adiposity at risk of CVD. Dilator capacity is not improved by six months high dose statin treatment.
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Bruce KD, Cagampang FR, Argenton M, Zhang J, Ethirajan PL, Burdge GC, Bateman AC, Clough GF, Poston L, Hanson MA, McConnell JM, Byrne CD. Maternal high-fat feeding primes steatohepatitis in adult mice offspring, involving mitochondrial dysfunction and altered lipogenesis gene expression. Hepatology 2009; 50:1796-808. [PMID: 19816994 DOI: 10.1002/hep.23205] [Citation(s) in RCA: 326] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
UNLABELLED Nonalcoholic fatty liver disease (NAFLD) describes an increasingly prevalent spectrum of liver disorders associated with obesity and metabolic syndrome. It is uncertain why steatosis occurs in some individuals, whereas nonalcoholic steatohepatitis (NASH) occurs in others. We have generated a novel mouse model to test our hypothesis: that maternal fat intake contributes to the development of NAFLD in adult offspring. Female mice were fed either a high-fat (HF) or control chow (C) diet before and during gestation and lactation. Resulting offspring were fed either a C or a HF diet after weaning, to generate four offspring groups; HF/HF, HF/C, C/HF, C/C. At 15 weeks of age, liver histology was normal in both the C/C and HF/C offspring. Kleiner scoring showed that although the C/HF offspring developed nonalcoholic fatty liver, the HF/HF offspring developed NASH. At 30 weeks, histological analysis and Kleiner scoring showed that both the HF/C and C/HF groups had NAFLD, whereas the HF/HF had a more severe form of NASH. Therefore, exposure to a HF diet in utero and during lactation contributes toward NAFLD progression. We investigated the mechanisms by which this developmental priming is mediated. At 15 weeks of age, hepatic mitochondrial electron transport chain (ETC) enzyme complex activity (I, II/III, and IV) was reduced in both groups of offspring from HF-fed mothers (HF/C and HF/HF). In addition, measurement of hepatic gene expression indicated that lipogenesis, oxidative stress, and inflammatory pathways were up-regulated in the 15-week-old HF/C and HF/HF offspring. CONCLUSION Maternal fat intake contributes toward the NAFLD progression in adult offspring, which is mediated through impaired hepatic mitochondrial metabolism and up-regulated hepatic lipogenesis.
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Stenken JA, Church MK, Gill CA, Clough GF. How minimally invasive is microdialysis sampling? A cautionary note for cytokine collection in human skin and other clinical studies. AAPS JOURNAL 2009; 12:73-8. [PMID: 19950008 DOI: 10.1208/s12248-009-9163-7] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2009] [Accepted: 11/16/2009] [Indexed: 01/05/2023]
Abstract
It is common to refer to microdialysis as a minimally invasive procedure, likening it to insertion of an artificial capillary. While a comparison of this type allows the process to be easily visualized by those outside the field, it tends to provide a false impression of the localized perturbation of the tissue space that is caused by catheter insertion. With the increased acceptance of microdialysis sampling as a viable in vivo sampling method, many researchers have begun to use the technique to explore inflammatory and immune-mediated diseases in the skin and other organs. Unfortunately, many of the molecules of interest, particularly chemokines and cytokines, are known to be generated during the inflammatory response to wounding and the subsequent cellular events leading to wound repair. With more than 11,000 reports citing the use of microdialysis sampling, only a few researchers have sought to assess the tissue damage that is incurred by probe insertion. For this reason, caution is warranted when collecting these molecules and inferring a role for them in clinical disease states. This commentary seeks to remind the research community of the confounding effects that signaling molecules related to the wounding response will have on clinical studies. Proper controls must be incorporated into all studies in order to assess whether or not particular molecules are truly related to the disease state under investigation or have been generated as part of the tissue response to the wound incurred by microdialysis catheter implantation.
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Avery MR, Voegeli D, Byrne CD, Simpson DM, Clough GF. Age and Cigarette Smoking are Independently Associated with the Cutaneous Vascular Response to Local Warming. Microcirculation 2009; 16:725-34. [DOI: 10.3109/10739680903199194] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Turzyniecka M, Wild SH, Krentz AJ, Chipperfield AJ, Gamble J, Clough GF, Byrne CD. Skeletal muscle microvascular exchange capacity is associated with hyperglycaemia in subjects with central obesity. Diabet Med 2009; 26:1112-9. [PMID: 19929989 DOI: 10.1111/j.1464-5491.2009.02822.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
AIMS Poor glycaemic control is associated with increased risk of microvascular disease in various organs including the eye and kidney, but the relationship between glycated haemoglobin (HbA(1c)) and microvascular function in skeletal muscle has not been described. We tested the association between HbA(1c) and a measure of microvascular exchange capacity (K(f)) in skeletal muscle in people with central obesity at risk of developing Type 2 diabetes. METHODS Microvascular function was measured in 28 women and 19 men [mean (+/- sd) age 51 +/- 9 years] with central obesity who did not have diabetes. We estimated insulin sensitivity by hyperinsulinaemic-euglycaemic clamp, visceral and total fatness by magnetic resonance imaging, fitness (VO(2) max by treadmill testing), physical activity energy expenditure [metabolic equivalents of tasks (METS) by use of the SenseWear Pro armband] and skeletal muscle microvascular exchange capacity (K(f)) by venous occlusion plethysmography. RESULTS In regression modelling, age, sex and fasting plasma glucose accounted for 30.5% of the variance in HbA(1c) (r(2) = 0.31, P = 0.001). Adding K(f) to this model explained an additional 26.5% of the variance in HbA(1c) (r(2) = 0.57, P = 0.0001 and K(f) was strongly and independently associated with HbA(1c) (standardized B coefficient -0.45 (95% confidence interval -0.19, -0.06), P = 0.001). CONCLUSIONS We found a strong negative independent association between a measure of skeletal muscle microvascular exchange capacity (K(f)) and HbA(1c). K(f) was associated with almost as much of the variance in HbA(1c) as fasting plasma glucose.
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Clough GF, Egginton S. Vasomotion and insulin-mediated capillary recruitment--part of the explanation? J Physiol 2009; 587:3407-8. [PMID: 19602627 DOI: 10.1113/jphysiol.2009.174557] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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Clough GF, Turzyniecka M, Walter L, Krentz AJ, Wild SH, Chipperfield AJ, Gamble J, Byrne CD. Muscle microvascular dysfunction in central obesity is related to muscle insulin insensitivity but is not reversed by high-dose statin treatment. Diabetes 2009; 58:1185-91. [PMID: 19208914 PMCID: PMC2671046 DOI: 10.2337/db08-1688] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE To test the hypotheses that decreased insulin-mediated glucose disposal in muscle is associated with a reduced muscle microvascular exchange capacity (Kf) and that 6 months of high-dose statin therapy would improve microvascular function in people with central obesity. RESEARCH DESIGN AND METHODS We assessed skeletal muscle microvascular function, visceral fat mass, physical activity levels, fitness, and insulin sensitivity in skeletal muscle in 22 female and 17 male volunteers with central obesity whose age (mean +/- SD) was 51 +/- 9 years. We tested the effect of atorvastatin (40 mg daily) on muscle microvascular function in a randomized, double-blind, placebo-controlled trial lasting 6 months. RESULTS Kf was negatively associated with a measure of glycemia (A1C; r = -0.44, P = 0.006) and positively associated with insulin sensitivity (the ratio of insulin-stimulated glucose effectiveness, or M value, to the mean insulin concentration, or I value; r = 0.39, P = 0.02). In regression modeling, A1C, visceral fat mass, and M:I explained 38% of the variance in Kf (in a linear regression model with Kf as the outcome [R2 = 0.38, P = 0.005]). M:I was associated with Kf independently of visceral fat mass (B coefficient 3.13 [95% CI 0.22-6.02], P = 0.036). Although 6 months' treatment with atorvastatin decreased LDL cholesterol by 51% (P < 0.001) and plasma high-sensitivity C-reactive protein by 75% (P = 0.02), microvascular function was unchanged. CONCLUSIONS Decreased insulin-mediated glucose uptake in skeletal muscle is associated with impaired muscle microvascular exchange capacity (Kf), independently of visceral fat mass. Muscle microvascular function is not improved by 6 months of high-dose statin treatment, despite marked statin-mediated improvements in lipid metabolism and decreased inflammation.
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Wetherell JR, Armstrong SJ, Read RW, Clough GF. VX Penetration Following Percutaneous Poisoning: A Dermal Microdialysis Study in the Guinea Pig. Toxicol Mech Methods 2008; 18:313-21. [DOI: 10.1080/15376510701884944] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Rodford JL, Torrens C, Siow RCM, Mann GE, Hanson MA, Clough GF. Endothelial dysfunction and reduced antioxidant protection in an animal model of the developmental origins of cardiovascular disease. J Physiol 2008; 586:4709-20. [PMID: 18669533 DOI: 10.1113/jphysiol.2008.156976] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Endothelial dysfunction underlies cardiovascular disease (CVD) in humans and is reported in animal models of developmental origins of such disease. We have investigated whether impaired antioxidant defences and NO generation underlie the genesis of endothelial dysfunction and operate as part of the normal processes of developmental plasticity regulating the induction of phenotype in the offspring. Female Wistar rats were fed either a control (C, 18% protein) or protein-restricted (PR, 9% protein) diet throughout pregnancy. Dams and pups were returned to standard laboratory chow post partum. In male offspring, PR resulted in a reduced endothelial responsiveness to acetylcholine (P < 0.05) in resistance arteries, with vascular remodelling evident from a reduction in smooth muscle content. mRNA expression of endothelial NO synthase (eNOS) was increased (P < 0.05) but there was no change in mRNA levels of manganese superoxide dismutase (MnSOD) or glutamate cysteine ligase (GCL) expression. Interestingly, expression of the antioxidant enzyme haem oxygenase-1 (HO-1) was reduced in the liver (P < 0.05). Female PR offspring also showed a reduced endothelial responsiveness but exhibited no changes in expression of eNOS, iNOS, soluble guanylate cyclase (sGC) or antioxidant genes. Thus, in this model of the developmental origins of CVD, the structure and function of resistance arteries in offspring is altered in complex ways which cannot simply be explained by attenuation in vascular eNOS or in antioxidant protection afforded by GCL or MnSOD. The dysfunction in male offspring may partially be counteracted by an up-regulation of eNOS expression; however, PR does lead to reduced HO-1 expression in these offspring, which may affect both their growth and vascular function. Our findings have established that PR induces significant phenotypic changes in male offspring that may be indicative of an adaptive response during development.
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