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Kaya M, Balasubramanian V, Li JKJ. Inadequacy of Augmentation Index for Monitoring Arterial Stiffness: Comparison with Arterial Compliance and Other Hemodynamic Variables. Cardiovasc Eng Technol 2022; 13:590-602. [PMID: 35102522 DOI: 10.1007/s13239-021-00605-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 12/14/2021] [Indexed: 01/09/2023]
Abstract
PURPOSE Augmentation Index (AIx) is used clinically for monitoring both wave reflections and arterial stiffness, which when increased is a risk factor of cardiovascular mortality and morbidity. We hypothesize that AIx is not solely related to vascular stiffness as described by arterial compliance and other hemodynamic parameters since AIx underestimates wave reflections. METHODS Aortic pressure and flow datasets (n = 42) from mongrel dogs were obtained from our experiments and Mendeley Data under various conditions. Arterial compliances based on the Windkessel model (Ct), the stroke volume (SV) to pulse pressure (PP) ratio (Cv = SV/PP), and at inflection pressure point (CPi) were computed. Other relevant hemodynamic factors are also computed. RESULTS AIx was poorly associated with arterial stiffness calculated from Ct (r = 0.299, p = 0.058) or CPi (r = 0.203, p = 0.203), even when adjusted for heart rates. Ct and Cv were monotonically associated. Alterations in inflection pressure (Pi) did not follow the changes in pulse pressure (PP) (r = 0.475, p = 0.002), and Pi was quantitatively similar to systolic pressure (r = 0.940, p < 0.001). CONCLUSION AIx is neither linearly correlated with arterial stiffness, nor with arterial compliance and several cardiac and arterial parameters have to be considered when AIx is calculated.
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Affiliation(s)
- Mehmet Kaya
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, 150 W University Blvd, Melbourne, FL, 32901, USA.
| | - Vignesh Balasubramanian
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, 150 W University Blvd, Melbourne, FL, 32901, USA
| | - John K-J Li
- Department of Biomedical Engineering and Robert Wood Johnson Medical School, Rutgers University, 599 Taylor Road, Piscataway, NJ, 08854, USA
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Okamoto T, Hashimoto Y, Ogawa M. Central Haemodynamics Are Associated With Pulmonary Function in Postmenopausal Women. Heart Lung Circ 2021; 30:1778-1784. [PMID: 34456129 DOI: 10.1016/j.hlc.2021.08.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 07/29/2021] [Accepted: 08/05/2021] [Indexed: 10/20/2022]
Abstract
PURPOSE Increased arterial stiffness predicts cardiovascular disease, which is associated with deteriorated pulmonary function and worsened chronic obstructive pulmonary disease. The present study examined whether arterial function was associated with pulmonary function in postmenopausal women. METHODS This study evaluated 41 postmenopausal women (age range: 59-85 years). Arterial function was measured as central systolic blood pressure (cSBP), central pulse pressure (cPP), brachial systolic BP (bSBP), brachial diastolic BP (bDBP), brachial PP (bPP), brachial mean arterial pressure (bMAP) and the augmentation index (AIx). AIx was adjusted for a heart rate of 75 beats per minute (bpm) (AIx@75) and served as the index of arterial stiffness determined by the reflected wave at the central artery. Pulmonary function was measured as forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1) and the FEV1/FVC ratio. RESULTS Univariate regression analysis demonstrated that cPP, bDBP and bPP were correlated with FVC and FEV1 (p<0.05, respectively), while AI@75 was correlated with FVC, FEV1 and FEV1/FVC ratio (p<0.01, respectively). A stepwise multivariate regression analysis revealed that bDBP was independently associated with FVC (p=0.032), while AI@75 was independently associated with FVC, FEV1 and FEV1/FVC ratio (p=0.001, p=0.003 and p=0.017, respectively). The FVC, FEV1 and FEV1/FVC ratio were lower in participants with a high AIx versus with a low AIx (p=0.0001, p=0.001 and p=0.044, respectively). CONCLUSION These results suggest that increased AIx is associated with lower pulmonary function in postmenopausal women.
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Affiliation(s)
- Takanobu Okamoto
- Department of Exercise Physiology, Nippon Sport Science University, Tokyo, Japan; Research Institute for Sport Science, Nippon Sport Science University, Tokyo, Japan.
| | - Yuto Hashimoto
- Department of Exercise Physiology, Nippon Sport Science University, Tokyo, Japan
| | - Madoka Ogawa
- Department of Sports Sociology and Health Sciences, Kyoto Sangyo University, Kyoto, Japan; Research Institute for Sport Science, Nippon Sport Science University, Tokyo, Japan
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Augmentation index in the assessment of wave reflections and systolic loading. Comput Biol Med 2019; 113:103418. [PMID: 31493580 DOI: 10.1016/j.compbiomed.2019.103418] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Revised: 08/26/2019] [Accepted: 08/26/2019] [Indexed: 01/17/2023]
Abstract
BACKGROUND Augmentation index (AIx) is used to quantify the augmented systolic aortic pressure that impedes ventricular ejection. Its use as an index of wave reflections is questionable. We hypothesize that AIx is quantitatively different from the reflection coefficient under varied physiological conditions. METHODS 42 datasets of aortic pressure and flow waveforms were obtained during induced hypertension (methoxamine infusion) and vasodilation (nitroprusside infusion) in our mongrel dog experiments (n = 5) and from Mendeley data during various interventions (vasoconstrictors, vasodilators, pacing, stimulation, hemorrhage and hemodilution). Wave reflections and principal components of reflection coefficients were computed for comparison to AIx and heart rate normalized AIx. RESULTS: Principal reflection coefficient, Γ1, increased in hypertension and decreased in vasodilation, hemorrhage and hemodilution. AIx followed the trend in many cases but was consistently lower than Γ1 in almost all the subjects. The Bland-Altman analysis also showed that both AIx and normalized AIx underestimated Γ1. The relationship between augmentation index and reflection coefficient was explained by a linear regression model (r2 = 0.23, p < 0.01) in which AIx followed directional changes in Γ1 and the normalization of AIx resulted in a linear model that explained less variation in the relationship between AIx and Γ1. CONCLUSION AIx is a reasonable clinical trend indicator, albeit not an accurate surrogate measure of the amount of wave reflections.
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Climie RE, Schultz MG, Fell JW, Romero L, Otahal P, Sharman JE. Central-to-brachial blood pressure amplification in type 2 diabetes: a systematic review and meta-analysis. J Hum Hypertens 2018; 33:94-105. [DOI: 10.1038/s41371-018-0124-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 08/24/2018] [Accepted: 09/10/2018] [Indexed: 11/09/2022]
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Climie RED, Picone DS, Sharman JE. Longitudinal Changes in Excess Pressure Independently Predict Declining Renal Function Among Healthy Individuals-A Pilot Study. Am J Hypertens 2017; 30:772-775. [PMID: 28575172 DOI: 10.1093/ajh/hpx091] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Accepted: 05/10/2017] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Aortic reservoir function independently predicts end-organ damage in cross-sectional analyses. However, longitudinal associations are more important regarding causation, but this has never been examined at rest or in response to light-moderate intensity exercise. The aim of this study was to determine the association between the change in aortic reservoir characteristics, in particular excess pressure integral (Pexcess) at rest and in response to exercise and the change in kidney function among healthy individuals followed over time. METHODS Aortic reservoir function (Pexcess and reservoir pressure), aortic stiffness, brachial and central blood pressure (BP), and renal function (estimated glomerular filtration rate [eGFR]) were recorded among 33 healthy individuals (57 ± 9 years; 55% male) at baseline and after an average 3.0 ± 0.3 years. RESULTS Over the follow up period, there was a significant increase in resting brachial BP, central BP, Pexcess, and aortic stiffness (P < 0.05 all). The change over time in resting Pexcess (but not aortic stiffness) was significantly related to the change in eGFR (r = -0.38, P = 0.038) and remained independent of age at follow up, change in 24-hour ambulatory systolic BP and body mass index (β = -0.0300, P = 0.043). There was no association between the change in aortic pulse wave velocity and the change eGFR (P = 0.46) nor were there any associations with exercising hemodynamics. CONCLUSIONS Pexcess is independently associated with a decline in renal function among healthy people followed over 3 years. These novel findings indicate the need to determine the underlying physiological determinants of aortic reservoir function.
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Affiliation(s)
- Rachel E D Climie
- Baker Heart and Diabetes Institute, Melbourne, Australia
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia
| | - Dean S Picone
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia
| | - James E Sharman
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia
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Peñaherrera CA, Peñaherrera R, Duarte MC, Peñaherrera E. Assessment of arterial stiffness in patients with metabolic syndrome in Ecuador: A cross-sectional study. Diabetes Metab Syndr 2017; 11:199-202. [PMID: 27612397 DOI: 10.1016/j.dsx.2016.09.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 09/03/2016] [Indexed: 12/20/2022]
Abstract
BACKGROUND Metabolic syndrome increases cardiovascular risk, and causes damage to the vascular wall. Through this mechanism, it might increase arterial rigidity, leading to further complications and heart strain. The use of a device that measures arterial rigidity can help determine if metabolic syndrome is related to a higher vascular stiffness and changes in estimated arterial age. METHODOLOGY Cross-sectional study at Luis Vernaza hospital of Guayaquil, Ecuador. Inpatients and outpatients from the Department of Cardiology with a full blood panel and echocardiogram were included. We used the IDF criteria to diagnose metabolic syndrome and measured arterial rigidity parameters in all of them, including augmentation indexes, central blood pressure, pulse wave velocity and arterial age. RESULTS 95 patients were included for analysis, 44.2% were females and 55.8% were males. Mean age was 61.7 years (±13.1). Metabolic syndrome was diagnosed in 49.5% of our patients and it was significantly more prevalent in women. We found significant differences in PWV, augmentation indexes, and peripheral and central blood pressure between metabolic and non-metabolic syndrome patients. There was a non-significant relationship between estimated arterial age and metabolic syndrome (p=0.32). CONCLUSION Patients with metabolic syndrome have an increased arterial rigidity. This, added to the high prevalence of the disease we found in our sample, shows the high cardiovascular risk these patients are at. A multidisciplinary approach to management is needed, along with patient collaboration. The introduction of these devices to measure arterial stiffness in developing countries can improve diagnosis and therapy of patients with cardio-metabolic conditions.
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Affiliation(s)
| | | | - Maria C Duarte
- Department of Cardiology, Luis Vernaza Hospital, Guayaquil, Ecuador
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Dalan R, Liew H, Assam PN, Chan ES, Siddiqui FJ, Tan AW, Chew DE, Boehm BO, Leow MK. A randomised controlled trial evaluating the impact of targeted vitamin D supplementation on endothelial function in type 2 diabetes mellitus: The DIMENSION trial. Diab Vasc Dis Res 2016; 13:192-200. [PMID: 26818228 PMCID: PMC4834510 DOI: 10.1177/1479164115621667] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
We sought to determine if vitamin D supplementation, to target 25(OH)D concentrations of 30-40 ng/mL, improves endothelial function in Singapore's multi-ethnic type 2 diabetes mellitus population. We randomised 64 type 2 diabetes mellitus patients with hypovitaminosis D to cholecalciferol 4000 International Unit/matching placebo [baseline 25(OH)D < 20 ng/mL] or cholecalciferol 2000 International Unit/matching placebo [baseline 25(OH)D: 20-30 ng/mL] daily for 16 weeks with a down titration at 8 weeks if 25(OH)D > 30 ng/mL. Endothelial function was assessed by peripheral tonometry (reactive hyperaemia index-endothelial peripheral arterial tonometry) and vascular biomarkers: E-selectin, von-Willebrand factor and high-sensitivity C-reactive protein. We compared the change from baseline parameters in the two groups using Student's t-test or Kruskal-Wallis test. A log-normal multivariate regression analysis was used to adjust for relevant baseline variables. The median reactive hyperaemia index in the vitamin D group increased from 0.65 (interquartile range: 0.42) to 0.73 (interquartile range: 0.36), whereas it decreased from 0.73 (interquartile range: 0.65) to 0.65 (interquartile range: 0.38) (p = 0.02) in the placebo group. After adjustment for baseline variables, the change was not statistically significant for reactive hyperaemia index (p = 0.07) and for other vascular biomarkers (p > 0.05). Targeted vitamin D supplementation for 16 weeks resulted in a small but non-significant improvement in endothelial function in a type 2 diabetes mellitus cohort.
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Affiliation(s)
- Rinkoo Dalan
- Department of Endocrinology, Tan Tock Seng Hospital, Singapore Yong Loo Lin School of Medicine, National University of Singapore, Singapore DUKE-NUS Medical School, National University of Singapore, Singapore Metabolic Medicine Research Program, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Huiling Liew
- Department of Endocrinology, Tan Tock Seng Hospital, Singapore
| | - Pryseley Nkouibert Assam
- Department of Biostatistics, Singapore Clinical Research Institute, Singapore Centre for Quantitative Medicine, Duke-NUS Graduate Medical School, National University of Singapore, Singapore
| | - Edwin Sy Chan
- Department of Biostatistics, Singapore Clinical Research Institute, Singapore Centre for Quantitative Medicine, Duke-NUS Graduate Medical School, National University of Singapore, Singapore
| | - Fahad Javaid Siddiqui
- Department of Biostatistics, Singapore Clinical Research Institute, Singapore Centre for Quantitative Medicine, Duke-NUS Graduate Medical School, National University of Singapore, Singapore
| | - Alvin Wk Tan
- Department of Endocrinology, Tan Tock Seng Hospital, Singapore
| | - Daniel Ek Chew
- Department of Endocrinology, Tan Tock Seng Hospital, Singapore
| | - Bernhard O Boehm
- Department of Endocrinology, Tan Tock Seng Hospital, Singapore Metabolic Medicine Research Program, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore Imperial College London, London, UK
| | - Melvin Ks Leow
- Department of Endocrinology, Tan Tock Seng Hospital, Singapore Singapore Institute for Clinical Sciences, A*STAR, Singapore National Healthcare Group, Singapore
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Yeboah K, Antwi DA, Gyan B. Arterial Stiffness in Nonhypertensive Type 2 Diabetes Patients in Ghana. Int J Endocrinol 2016; 2016:6107572. [PMID: 27774104 PMCID: PMC5059649 DOI: 10.1155/2016/6107572] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 05/31/2016] [Accepted: 06/26/2016] [Indexed: 12/03/2022] Open
Abstract
Background. Increased arterial stiffness is an independent cardiovascular risk factor in diabetes patients and general population. However, the contribution of diabetes to arterial stiffness is often masked by coexistent obesity and hypertension. In this study, we assessed arterial stiffness in nonhypertensive, nonobese type 2 diabetes (T2DM) patients in Ghana. Methods. In case-control design, 166 nonhypertensive, nonobese participants, comprising 96 T2DM patients and 70 nondiabetes controls, were recruited. Peripheral and central blood pressure (BP) indices were measured, and arterial stiffness was assessed as aortic pulse wave velocity (PWVao), augmentation index (AIx), cardioankle vascular index (CAVI), and heart-ankle pulse wave velocity (haPWV). Results. With similar peripheral and central BP indices, T2DM patients had higher PWVao (8.3 ± 1 versus 7.8 ± 1.3, p = 0.044) and CAVI (7.9 ± 1.2 versus 6.9 ± 0.7, p = 0.021) than nondiabetic control. AIx and haPWV were similar between T2DM and nondiabetic controls. Multiple regression models showed that, in the entire study participants, the major determinants of PWVao were diabetes status, age, gender, systolic BP, and previous smoking status (β = 0.22, 0.36, 0.48, 0.21, and 0.25, resp.; all p < 0.05); the determinants of CAVI were diabetes status, age, BMI, heart rate, HbA1c, total cholesterol, HDL cholesterol, and previous smoking status (β = 0.21, 0.38, 0.2, 0.18, 0.24. 0.2, -0.19, and 0.2, resp.; all p < 0.05). Conclusion. Our findings suggest that nonhypertensive, nonobese T2DM patients have increased arterial stiffness without appreciable increase in peripheral and central pressure indices.
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Affiliation(s)
- Kwame Yeboah
- Department of Physiology, School of Allied & Biomedical Sciences, University of Ghana, Accra, Ghana
- *Kwame Yeboah:
| | - Daniel A. Antwi
- Department of Physiology, School of Allied & Biomedical Sciences, University of Ghana, Accra, Ghana
| | - Ben Gyan
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
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Brachial-to-radial systolic blood pressure amplification in patients with type 2 diabetes mellitus. J Hum Hypertens 2015; 30:404-9. [DOI: 10.1038/jhh.2015.101] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2015] [Revised: 07/31/2015] [Accepted: 09/01/2015] [Indexed: 11/08/2022]
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Schultz MG, Hughes AD, Davies JE, Sharman JE. Associations and clinical relevance of aortic-brachial artery stiffness mismatch, aortic reservoir function, and central pressure augmentation. Am J Physiol Heart Circ Physiol 2015; 309:H1225-33. [PMID: 26276816 DOI: 10.1152/ajpheart.00317.2015] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 08/12/2015] [Indexed: 01/09/2023]
Abstract
Central augmentation pressure (AP) and index (AIx) predict cardiovascular events and mortality, but underlying physiological mechanisms remain disputed. While traditionally believed to relate to wave reflections arising from proximal arterial impedance (and stiffness) mismatching, recent evidence suggests aortic reservoir function may be a more dominant contributor to AP and AIx. Our aim was therefore to determine relationships among aortic-brachial stiffness mismatching, AP, AIx, aortic reservoir function, and end-organ disease. Aortic (aPWV) and brachial (bPWV) pulse wave velocity were measured in 359 individuals (aged 61 ± 9, 49% male). Central AP, AIx, and aortic reservoir indexes were derived from radial tonometry. Participants were stratified by positive (bPWV > aPWV), negligible (bPWV ≈ aPWV), or negative stiffness mismatch (bPWV < aPWV). Left-ventricular mass index (LVMI) was measured by two-dimensional-echocardiography. Central AP and AIx were higher with negative stiffness mismatch vs. negligible or positive stiffness mismatch (11 ± 6 vs. 10 ± 6 vs. 8 ± 6 mmHg, P < 0.001 and 24 ± 10 vs. 24 ± 11 vs. 21 ± 13%, P = 0.042). Stiffness mismatch (bPWV-aPWV) was negatively associated with AP (r = -0.18, P = 0.001) but not AIx (r = -0.06, P = 0.27). Aortic reservoir pressure strongly correlated to AP (r = 0.81, P < 0.001) and AIx (r = 0.62, P < 0.001) independent of age, sex, heart rate, mean arterial pressure, and height (standardized β = 0.61 and 0.12, P ≤ 0.001). Aortic reservoir pressure independently predicted abnormal LVMI (β = 0.13, P = 0.024). Positive aortic-brachial stiffness mismatch does not result in higher AP or AIx. Aortic reservoir function, rather than discrete wave reflection from proximal arterial stiffness mismatching, provides a better model description of AP and AIx and also has clinical relevance as evidenced by an independent association of aortic reservoir pressure with LVMI.
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Affiliation(s)
- Martin G Schultz
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia
| | - Alun D Hughes
- Institute for Cardiovascular Science, University College London, London, United Kingdom; and
| | - Justin E Davies
- International Centre for Circulatory Health, Imperial College London, London, United Kingdom
| | - James E Sharman
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia;
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Karpievitch YV, Nikolic SB, Wilson R, Sharman JE, Edwards LM. Metabolomics data normalization with EigenMS. PLoS One 2014; 9:e116221. [PMID: 25549083 PMCID: PMC4280143 DOI: 10.1371/journal.pone.0116221] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 12/03/2014] [Indexed: 12/26/2022] Open
Abstract
Liquid chromatography mass spectrometry has become one of the analytical platforms of choice for metabolomics studies. However, LC-MS metabolomics data can suffer from the effects of various systematic biases. These include batch effects, day-to-day variations in instrument performance, signal intensity loss due to time-dependent effects of the LC column performance, accumulation of contaminants in the MS ion source and MS sensitivity among others. In this study we aimed to test a singular value decomposition-based method, called EigenMS, for normalization of metabolomics data. We analyzed a clinical human dataset where LC-MS serum metabolomics data and physiological measurements were collected from thirty nine healthy subjects and forty with type 2 diabetes and applied EigenMS to detect and correct for any systematic bias. EigenMS works in several stages. First, EigenMS preserves the treatment group differences in the metabolomics data by estimating treatment effects with an ANOVA model (multiple fixed effects can be estimated). Singular value decomposition of the residuals matrix is then used to determine bias trends in the data. The number of bias trends is then estimated via a permutation test and the effects of the bias trends are eliminated. EigenMS removed bias of unknown complexity from the LC-MS metabolomics data, allowing for increased sensitivity in differential analysis. Moreover, normalized samples better correlated with both other normalized samples and corresponding physiological data, such as blood glucose level, glycated haemoglobin, exercise central augmentation pressure normalized to heart rate of 75, and total cholesterol. We were able to report 2578 discriminatory metabolite peaks in the normalized data (p<0.05) as compared to only 1840 metabolite signals in the raw data. Our results support the use of singular value decomposition-based normalization for metabolomics data.
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Affiliation(s)
- Yuliya V. Karpievitch
- School of Mathematics and Physics, University of Tasmania, Hobart, TAS, Australia
- * E-mail:
| | - Sonja B. Nikolic
- Menzies Research Institute Tasmania, University of Tasmania, Hobart, TAS, Australia
| | - Richard Wilson
- Central Science Laboratory, University of Tasmania, Hobart, TAS, Australia
| | - James E. Sharman
- Central Science Laboratory, University of Tasmania, Hobart, TAS, Australia
| | - Lindsay M. Edwards
- Centre of Human & Aerospace Physiological Sciences, King’s College London, London, United Kingdom
- Fibrosis Discovery Performance Unit, GlaxoSmithKline R&D, Stevenage, United Kingdom
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Climie RED, Srikanth V, Beare R, Keith LJ, Fell J, Davies JE, Sharman JE. Aortic reservoir characteristics and brain structure in people with type 2 diabetes mellitus; a cross sectional study. Cardiovasc Diabetol 2014; 13:143. [PMID: 25338824 PMCID: PMC4221700 DOI: 10.1186/s12933-014-0143-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 10/06/2014] [Indexed: 01/09/2023] Open
Abstract
Background Central hemodynamics help to maintain appropriate cerebral and other end-organ perfusion, and may be altered with ageing and type 2 diabetes mellitus (T2DM). We aimed to determine the associations between central hemodynamics and brain structure at rest and during exercise in people with and without T2DM. Methods In a sample of people with T2DM and healthy controls, resting and exercise measures of aortic reservoir characteristics (including excess pressure integral [Pexcess]) and other central hemodynamics (including augmentation index [AIx] and aortic pulse wave velocity [aPWV]) were recorded. Brain volumes (including gray matter volume [GMV] and white matter lesions [WML]) were derived from magnetic resonance imaging (MRI) scans. Multivariable linear regression was used to study the associations of hemodynamic variables with brain structure in the two groups adjusting for age, sex, daytime systolic BP (SBP) and heart rate. Results There were 37 T2DM (63 ± 9 years; 47% male) and 37 healthy individuals (52 ± 8 years; 51% male). In T2DM, resting aPWV was inversely associated with GMV (standardized β = −0.47, p = 0.036). In healthy participants, resting Pexcess was inversely associated with GMV (β = −0.23, p = 0.043) and AIx was associated with WML volume (β = 0.52, p = 0.021). There were no associations between exercise hemodynamics and brain volumes in either group. Conclusions Brain atrophy is associated with resting aortic stiffness in T2DM, and resting Pexcess in healthy individuals. Central vascular mechanisms underlying structural brain changes may differ between healthy individuals and T2DM.
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