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Chambers JC, Tan ST, Zhang WH, Sehmi J, Al-Hussaini A, Ramasamy M, Scott J, Elliott P, Kooner JS. 114 Whole genome sequencing to identify genetic variants underlying cardiovascular disease among Indian Asians. Heart 2012. [DOI: 10.1136/heartjnl-2012-301877b.114] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Tan ST, Sehmi J, Al-Hussaini A, Ala-Korpela M, Elliott P, Chambers JC, Kooner JS. 151 Nuclear magnetic resonance profiling of serum identifies novel biomarker associated with coronary atherosclerosis. Heart 2012. [DOI: 10.1136/heartjnl-2012-301877b.151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Li H, Kilpeläinen TO, Liu C, Zhu J, Liu Y, Hu C, Yang Z, Zhang W, Bao W, Cha S, Wu Y, Yang T, Sekine A, Choi BY, Yajnik CS, Zhou D, Takeuchi F, Yamamoto K, Chan JC, Mani KR, Been LF, Imamura M, Nakashima E, Lee N, Fujisawa T, Karasawa S, Wen W, Joglekar CV, Lu W, Chang Y, Xiang Y, Gao Y, Liu S, Song Y, Kwak SH, Shin HD, Park KS, Fall CHD, Kim JY, Sham PC, Lam KSL, Zheng W, Shu X, Deng H, Ikegami H, Krishnaveni GV, Sanghera DK, Chuang L, Liu L, Hu R, Kim Y, Daimon M, Hotta K, Jia W, Kooner JS, Chambers JC, Chandak GR, Ma RC, Maeda S, Dorajoo R, Yokota M, Takayanagi R, Kato N, Lin X, Loos RJF. Association of genetic variation in FTO with risk of obesity and type 2 diabetes with data from 96,551 East and South Asians. Diabetologia 2012; 55:981-95. [PMID: 22109280 PMCID: PMC3296006 DOI: 10.1007/s00125-011-2370-7] [Citation(s) in RCA: 146] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Accepted: 10/10/2011] [Indexed: 12/18/2022]
Abstract
AIMS/HYPOTHESIS FTO harbours the strongest known obesity-susceptibility locus in Europeans. While there is growing evidence for a role for FTO in obesity risk in Asians, its association with type 2 diabetes, independently of BMI, remains inconsistent. To test whether there is an association of the FTO locus with obesity and type 2 diabetes, we conducted a meta-analysis of 32 populations including 96,551 East and South Asians. METHODS All studies published on the association between FTO-rs9939609 (or proxy [r (2) > 0.98]) and BMI, obesity or type 2 diabetes in East or South Asians were invited. Each study group analysed their data according to a standardised analysis plan. Association with type 2 diabetes was also adjusted for BMI. Random-effects meta-analyses were performed to pool all effect sizes. RESULTS The FTO-rs9939609 minor allele increased risk of obesity by 1.25-fold/allele (p = 9.0 × 10(-19)), overweight by 1.13-fold/allele (p = 1.0 × 10(-11)) and type 2 diabetes by 1.15-fold/allele (p = 5.5 × 10(-8)). The association with type 2 diabetes was attenuated after adjustment for BMI (OR 1.10-fold/allele, p = 6.6 × 10(-5)). The FTO-rs9939609 minor allele increased BMI by 0.26 kg/m(2) per allele (p = 2.8 × 10(-17)), WHR by 0.003/allele (p = 1.2 × 10(-6)), and body fat percentage by 0.31%/allele (p = 0.0005). Associations were similar using dominant models. While the minor allele is less common in East Asians (12-20%) than South Asians (30-33%), the effect of FTO variation on obesity-related traits and type 2 diabetes was similar in the two populations. CONCLUSIONS/INTERPRETATION FTO is associated with increased risk of obesity and type 2 diabetes, with effect sizes similar in East and South Asians and similar to those observed in Europeans. Furthermore, FTO is also associated with type 2 diabetes independently of BMI.
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Affiliation(s)
- H. Li
- Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 294 Tai-Yuan Road, Shanghai, 200031 People’s Republic of China
| | - T. O. Kilpeläinen
- MRC Epidemiology Unit, Institute of Metabolic Science Box 285, Addenbrooke’s Hospital, Hills Road, Cambridge, CB2 0QQ UK
| | - C. Liu
- Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 294 Tai-Yuan Road, Shanghai, 200031 People’s Republic of China
| | - J. Zhu
- Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 294 Tai-Yuan Road, Shanghai, 200031 People’s Republic of China
| | - Y. Liu
- Institutes of Biomedical Sciences, Fudan University, Shanghai, People’s Republic of China
| | - C. Hu
- Shanghai Diabetes Institute, Department of Endocrinology and Metabolism, Shanghai Clinical Center of Diabetes, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, People’s Republic of China
| | - Z. Yang
- Department of Endocrinology and Metabolism, Huashan Hospital, Institute of Endocrinology and Diabetology at Fudan University, Shanghai Medical School, Fudan University, Shanghai, People’s Republic of China
| | - W. Zhang
- Department Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK
| | - W. Bao
- Department of Nutrition and Food Hygiene and MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People’s Republic of China
| | - S. Cha
- Division of Constitutional Medicine Research, Korea Institute of Oriental Medicine, Daejeon, South Korea
| | - Y. Wu
- Department of Genetics, University of North Carolina, Chapel Hill, NC USA
| | - T. Yang
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, and Institute of Molecular Genetics, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an, People’s Republic of China
| | - A. Sekine
- EBM Research Center, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - B. Y. Choi
- Department of Preventive Medicine, HanYang University College of Medicine, Seoul, South Korea
| | - C. S. Yajnik
- Diabetology Research Centre, KEM Hospital and Research Centre, Pune, India
| | - D. Zhou
- Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 294 Tai-Yuan Road, Shanghai, 200031 People’s Republic of China
| | - F. Takeuchi
- National Center for Global Health and Medicine, Tokyo, Japan
| | - K. Yamamoto
- Division of Genome Analysis, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - J. C. Chan
- Department of Medicine and Therapeutics, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong Special Administrative Region People’s Republic of China
| | - K. R. Mani
- Centre for Cellular and Molecular Biology (CCMB-CSIR), Hyderabad, India
| | - L. F. Been
- University of Oklahoma Health Sciences Center, Oklahoma City, OK USA
| | - M. Imamura
- Laboratory for Endocrinology and Metabolism, RIKEN Center for Genomic Medicine, Yokohama, Japan
| | - E. Nakashima
- Department of Diabetes and Endocrinology, Chubu Rosai Hospital, Nagoya, Japan
| | - N. Lee
- USC Office of Population Studies Foundation, University of San Carlos, Cebu, Philippines
| | - T. Fujisawa
- Department of Geriatric Medicine and Nephrology, Osaka University Graduate School of Medicine, Suita, Japan
| | - S. Karasawa
- Third Department of Internal Medicine, and Global Center of Excellence Program Study Group, Yamagata University School of Medicine, Yamagata, Japan
| | - W. Wen
- Division of Epidemiology, Department of Medicine, Vanderbilt School of Medicine, Nashville, TN USA
| | - C. V. Joglekar
- Diabetology Research Centre, KEM Hospital and Research Centre, Pune, India
| | - W. Lu
- Shanghai Institute of Preventive Medicine, Shanghai, People’s Republic of China
| | - Y. Chang
- National Taiwan University Hospital Bei-Hu branch, Taipei, Taiwan
| | - Y. Xiang
- Department of Epidemiology, Shanghai Cancer Institute, Shanghai, People’s Republic of China
| | - Y. Gao
- Department of Epidemiology, Shanghai Cancer Institute, Shanghai, People’s Republic of China
| | - S. Liu
- Center for Metabolic Disease Prevention, School of Public Health and David Geffen School of Medicine, UCLA, Los Angeles, CA USA
| | - Y. Song
- Division of Preventive Medicine, Brigham & Women’s Hospital, Harvard Medical School, Boston, MA USA
| | - S. H. Kwak
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, South Korea
| | - H. D. Shin
- Department of Life Science, Sogang University, Seoul, South Korea
| | - K. S. Park
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, South Korea
| | - C. H. D. Fall
- MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton General Hospital, Southampton, Hampshire UK
| | - J. Y. Kim
- Division of Constitutional Medicine Research, Korea Institute of Oriental Medicine, Daejeon, South Korea
| | - P. C. Sham
- Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, Hong Kong Special Administrative Region People’s Republic of China
| | - K. S. L. Lam
- Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, Hong Kong Special Administrative Region People’s Republic of China
| | - W. Zheng
- Division of Epidemiology, Department of Medicine, Vanderbilt School of Medicine, Nashville, TN USA
| | - X. Shu
- Division of Epidemiology, Department of Medicine, Vanderbilt School of Medicine, Nashville, TN USA
| | - H. Deng
- School of Medicine, University of Missouri, Kansas City, MO USA
- Center of Systematic Biomedical Research, University of Shanghai for Science and Technology, Shanghai, People’s Republic of China
- Institute of Bioscience and Biotechnology, School of Science, Beijing Jiaotong University, Beijing, People’s Republic of China
| | - H. Ikegami
- Department of Endocrinology, Metabolism and Diabetes, Kinki University School of Medicine, Osaka, Japan
| | - G. V. Krishnaveni
- Epidemiology Research Unit, Holdsworth Memorial Hospital, Mysore, India
| | - D. K. Sanghera
- University of Oklahoma Health Sciences Center, Oklahoma City, OK USA
| | - L. Chuang
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - L. Liu
- Department of Nutrition and Food Hygiene and MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People’s Republic of China
| | - R. Hu
- Department of Endocrinology and Metabolism, Huashan Hospital, Institute of Endocrinology and Diabetology at Fudan University, Shanghai Medical School, Fudan University, Shanghai, People’s Republic of China
| | - Y. Kim
- Department of Preventive Medicine, Dong-A University College of Medicine, Busan, South Korea
| | - M. Daimon
- Third Department of Internal Medicine, and Global Center of Excellence Program Study Group, Yamagata University School of Medicine, Yamagata, Japan
| | - K. Hotta
- EBM Research Center, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - W. Jia
- Shanghai Diabetes Institute, Department of Endocrinology and Metabolism, Shanghai Clinical Center of Diabetes, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, Shanghai, People’s Republic of China
| | - J. S. Kooner
- National Heart & Lung Institute, Hammersmith Hospital, Hammersmith Campus, Faculty of Medicine, Imperial College London, London, UK
| | - J. C. Chambers
- Department Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK
| | - G. R. Chandak
- Centre for Cellular and Molecular Biology (CCMB-CSIR), Hyderabad, India
| | - R. C. Ma
- Department of Medicine and Therapeutics, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong Special Administrative Region People’s Republic of China
| | - S. Maeda
- Laboratory for Endocrinology and Metabolism, RIKEN Center for Genomic Medicine, Yokohama, Japan
| | - R. Dorajoo
- Genome Institute of Singapore, Agency for Science, Technology and Research, Singapore, Republic of Singapore
- Department of Genomics of Common Disease, School of Public Health, Hammersmith Hospital, Imperial College London, London, UK
| | - M. Yokota
- Department of Genome Science, School of Dentistry, Aichi-Gakuin University, Nagoya, Japan
| | - R. Takayanagi
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - N. Kato
- National Center for Global Health and Medicine, Tokyo, Japan
| | - X. Lin
- Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 294 Tai-Yuan Road, Shanghai, 200031 People’s Republic of China
| | - R. J. F. Loos
- MRC Epidemiology Unit, Institute of Metabolic Science Box 285, Addenbrooke’s Hospital, Hills Road, Cambridge, CB2 0QQ UK
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Chahal N, Lim TK, Melderis S, Jain P, Chambers JC, Kooner JS, Senior R. 111 Increased carotid artery plaque burden is associated with reduced systolic left ventricular function and increased filling pressure in asymptomatic individuals. Heart 2010. [DOI: 10.1136/hrt.2010.196089.6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Gerber RT, Sharp ASP, Sachdev B, Tang K, Khamis R, Watson G, Patterson T, Badhusha N, Kooner JS. 033 Reproducibilty of the syntax score in a real world setting: implications for the choice of contemporary revascularisation strategy. Heart 2010. [DOI: 10.1136/hrt.2010.195958.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Gaemperli O, Liga R, Spyrou N, Rosen SD, Foale R, Kooner JS, Rimoldi OE, Camici PG. Myocardial -adrenoceptor down-regulation early after infarction is associated with long-term incidence of congestive heart failure. Eur Heart J 2010; 31:1722-9. [DOI: 10.1093/eurheartj/ehq138] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Zabaneh D, Chambers JC, Elliott P, Scott J, Balding DJ, Kooner JS. Heritability and genetic correlations of insulin resistance and component phenotypes in Asian Indian families using a multivariate analysis. Diabetologia 2009; 52:2585-9. [PMID: 19763535 DOI: 10.1007/s00125-009-1504-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2009] [Accepted: 08/03/2009] [Indexed: 11/25/2022]
Abstract
AIMS/HYPOTHESIS Insulin resistance and related metabolic disturbances are more common among Asian Indians than European whites. Little is known about the heritability of insulin resistance traits in Asian Indians. Our objective was to estimate heritabilities and genetic correlations in Asian Indian families. METHODS Phenotypic data were assembled for 181 UK Asian Indian probands with premature CHD, and their 1,454 first-, second- and third-degree relatives. We calculated (narrow-sense) heritabilities and genetic correlations for insulin resistance traits, and common environmental effects using all study participants and a multivariate model. The analysis was repeated in a subsample consisting of individuals not on drug therapy. RESULTS Heritability estimates (SE) for individuals not on drug therapy were: BMI 0.31 (0.04), WHR 0.27 (0.04), systolic BP 0.29 (0.03), triacylglycerol 0.40 (0.04), HDL-cholesterol 0.53 (0.04), glucose 0.37 (0.03), HOMA of insulin resistance (HOMA-IR) 0.22 (0.04), and HbA(1c) 0.60 (0.04). We observed many significant genetic correlations between the traits, in particular between HOMA-IR and BMI. Heritability estimates were lower for all phenotypes when analysed among all participants. CONCLUSIONS/INTERPRETATION Genetic factors contribute to a significant proportion of the total variance in insulin resistance and related metabolic disturbances in Asian Indian CHD families.
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Affiliation(s)
- D Zabaneh
- Department of Epidemiology and Public Health, Imperial College London, St Mary's Campus, Norfolk Place, London, W2 1PG, UK.
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Chahal NS, Lim TK, Jain P, Chambers JC, Kooner JS, Senior R. New insights into the relationship of left ventricular geometry and left ventricular mass with cardiac function: a population study of hypertensive subjects. Eur Heart J 2009; 31:588-94. [DOI: 10.1093/eurheartj/ehp490] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
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Chahal NS, Lim TK, Jain P, Chambers JC, Kooner JS, Senior R. Normative reference values for the tissue Doppler imaging parameters of left ventricular function: a population-based study. European Journal of Echocardiography 2009; 11:51-6. [DOI: 10.1093/ejechocard/jep164] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Roderick P, Lightstone L, Harris S, Lapsley M, Dockrell M, Lim E, Chambers J, Kooner JS. Prevalence of chronic kidney disease in South Asian and Black minorities: findings from a population based screening study in London, UK. Br J Soc Med 2009. [DOI: 10.1136/jech.2009.096727l] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Williams ED, Steptoe A, Chambers JC, Kooner JS. Psychosocial risk factors for coronary heart disease in UK South Asian men and women. J Epidemiol Community Health 2009; 63:986-91. [PMID: 19622519 DOI: 10.1136/jech.2008.084186] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND South Asian people in the UK and other western countries have elevated rates of coronary heart disease (CHD). Psychosocial factors contribute to CHD risk, but information about psychosocial risk profiles in UK South Asians is limited. This study aimed to examine the profile of conventional and novel psychosocial risk factors in South Asian compared with white men and women. METHODS Using a cross-sectional population study design, psychosocial profiles were assessed in 1130 South Asian and 818 white European healthy men and women aged between 35 and 75 years, who had previously participated in a cardiovascular risk assessment programme in West London. Psychosocial factors potentially contributing to CHD risk were assessed using standardised questionnaires. RESULTS UK South Asians reported significantly higher psychosocial adversity compared with UK whites. South Asian men and women experienced greater chronic stress, in the form of financial strain, residential crowding, family conflict, social deprivation and discrimination, than white Europeans. They had larger social networks, but reported lower social support and greater depression and hostility. These effects were largely independent of socioeconomic status. CONCLUSION UK South Asians experience significant psychosocial adversity compared with UK white Europeans. This is consistent with the heightened vulnerability to CHD observed in this population.
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Affiliation(s)
- E D Williams
- Department of Epidemiology and Public Health, University College London, London WC1E 6BT, UK.
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Hughes AD, Coady E, Raynor S, Mayet J, Wright AR, Shore AC, Kooner JS, Thom SAM, Chaturvedi N. Reduced endothelial progenitor cells in European and South Asian men with atherosclerosis. Eur J Clin Invest 2007; 37:35-41. [PMID: 17181565 PMCID: PMC1869046 DOI: 10.1111/j.1365-2362.2007.01743.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
BACKGROUND Circulating endothelial progenitor cells (EPCs) play a role in the repair and regeneration of the endothelium and may represent a novel cardiovascular risk factor. South Asian subjects have an increased risk of cardiovascular disease which is not fully explained by known risk factors. This study examined associations of EPCs with atherosclerosis and possible ethnic differences in EPCs. MATERIALS AND METHODS A population sample of 58 European and South Asian adult men was enriched with the recruitment of an additional 59 European and South Asian men with known coronary disease. The coronary artery calcification score was measured by multi-slice computerized tomography (CT), carotid and femoral intima-media thickness (IMT), and femoral plaques were measured by ultrasound. The subjects were further subdivided into three categories of coronary artery disease on the basis of coronary artery calcification score and clinical history. Total EPCs and non-senescent EPCs (ns-EPCs) were quantified after 5 days cell culture and the number of late outgrowth colonies was measured over a 6-week test period. Circulating CD34+ haematopoietic precursor cells were measured by flow cytometry. RESULTS Individuals with femoral plaques had reduced total and ns-EPCs. The number of ns-EPCs were reduced in individuals with the most coronary atheroma and were inversely related to the coronary calcification score and femoral IMT. These relationships persisted after multivariate adjustment for other risk factors. The numbers of late outgrowth colonies or circulating CD34+ cells were unrelated to the presence of atherosclerosis. There were no differences in the number of EPCs between European and South Asian subjects. CONCLUSION The number of EPCs are reduced in subjects with atherosclerosis independent of other risk factors. Reduction in EPC numbers may be an independent risk factor for atherosclerosis but does not explain ethnic differences in cardiovascular risk.
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Kapur A, Malik IS, Bagger JP, Anderson JR, Kooner JS, Thomas M, Punjabi P, Mayet J, Millane T, Goedicke J, Jamrozik K, de Belder MA, Hall RJ, Beatt KJ. The Coronary Artery Revascularisation in Diabetes (CARDia) trial: background, aims, and design. Am Heart J 2005; 149:13-9. [PMID: 15660030 DOI: 10.1016/j.ahj.2004.07.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Patients with diabetes have an increased incidence and severity of ischemic heart disease, which leads to an increased requirement for coronary revascularization. Comparative information regarding mode of revascularization--coronary artery bypass graft surgery surgery (CABG) or percutaneous coronary intervention (PCI)--is limited, mainly confined to a subanalysis of the Bypass Angioplasty Revascularization (BARI) trial, suggesting a mortality benefit of CABG over PCI. No prospective trial has specifically compared these modes of revascularization in patients with diabetes. OBJECTIVE The Coronary Artery Revascularisation in Diabetes (CARDia) trial is designed to address the hypothesis that optimal PCI is not inferior to modern CABG as a revascularization strategy for diabetics with multivessel or complex single-vessel coronary disease. The primary end point is a composite of death, nonfatal myocardial infarction, and cerebrovascular accident at 1 year. METHOD A total of 600 patients with diabetes are to be randomized to either PCI or CABG, with few protocol restrictions on operative techniques or use of new technology. This gives a power of 80% to detect non-inferiority of PCI assuming that the PCI 1-year event rate is 9%. A cardiac surgeon and a cardiologist must agree that a patient is suitable for revascularization by either technique prior to recruitment into the study. Twenty-one centers in the United Kingdom and Ireland are recruiting patients. Data on cost effectiveness, quality of life, and neurocognitive function are being collected. Long-term (3-5 year) follow-up data will also be collected.
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Affiliation(s)
- A Kapur
- Hammersmith Hospital, London, United Kingdom.
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Chambers JC, Ueland PM, Wright M, Doré CJ, Refsum H, Kooner JS. Investigation of relationship between reduced, oxidized, and protein-bound homocysteine and vascular endothelial function in healthy human subjects. Circ Res 2001; 89:187-92. [PMID: 11463727 DOI: 10.1161/hh1401.093459] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Previous studies investigating homocysteine and vascular disease have relied on total plasma homocysteine as the sole index of homocysteine status. We examined the dynamic relationship between vascular endothelial function and concentrations of total, protein-bound oxidized, free oxidized, and reduced homocysteine to identify the homocysteine form associated with endothelial dysfunction in humans. We investigated 14 healthy volunteers (10 men, 4 women). Brachial artery flow-mediated dilatation was measured at baseline and at 30, 60, 120, 240, and 360 minutes after oral (1) L-methionine (50 mg/kg), (2) L-homocysteine (5 mg/kg), and (3) placebo. Plasma concentrations of total, protein-bound oxidized, free oxidized, and reduced homocysteine were measured at each time point, and nitroglycerin-induced dilatation at was assessed at 0, 120, and 360 minutes. Flow-mediated dilatation fell, and concentrations of total, protein-bound oxidized, free oxidized, and reduced homocysteine increased after oral homocysteine and oral methionine (all P<0.05 for difference in time course compared with placebo). Flow-mediated dilatation showed a reciprocal relationship with reduced homocysteine during both homocysteine and methionine loading. In both loading studies, peak reduction in flow-mediated dilatation coincided with maximal reduced homocysteine concentrations. In contrast, there was no consistent relationship between flow-mediated dilatation and free oxidized homocysteine, protein-bound oxidized homocysteine, or related species. Nitroglycerin-induced dilatation was unchanged by oral homocysteine and oral methionine (P>0.10 compared with placebo). Reduced homocysteine is closely associated with endothelial dysfunction during oral methionine and oral homocysteine loading. Our observations support the hypothesis that reduced homocysteine is the deleterious form of homocysteine for vascular function in vivo and suggest a less important role for other homocysteine species.
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Affiliation(s)
- J C Chambers
- National Heart and Lung Institute, Department of Medical Statistics and Evaluation, Imperial College School of Medicine, Hammersmith Hospital, London, UK
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Chambers JC, Eda S, Bassett P, Karim Y, Thompson SG, Gallimore JR, Pepys MB, Kooner JS. C-reactive protein, insulin resistance, central obesity, and coronary heart disease risk in Indian Asians from the United Kingdom compared with European whites. Circulation 2001; 104:145-50. [PMID: 11447077 DOI: 10.1161/01.cir.104.2.145] [Citation(s) in RCA: 281] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Indian Asians in the United Kingdom have increased coronary heart disease (CHD) mortality compared with European whites, but the causes are not well understood. Increased circulating concentrations of C-reactive protein (CRP) are an independent risk factor for CHD. Therefore, we investigated this marker of inflammation in healthy UK Indian Asian and European white men. Methods and Results-- We measured serum CRP concentrations and conventional CHD risk factors in 1025 healthy male subjects (518 Indian Asians and 507 European whites) aged 35 to 60 years who were recruited at random from general practitioner lists. The geometric mean CRP concentration was 17% higher (95% confidence interval, 3% to 33%) in Indian Asians compared with European whites. CRP values were strongly associated with conventional CHD risk factors, measures of obesity, and metabolic disturbances associated with insulin resistance in both racial groups. The difference in CRP concentrations between Indian Asians and European whites remained after adjustment for conventional CHD risk factors but was eliminated by an adjustment for central obesity and insulin resistance score in Asians. On the basis of these results, we estimate that the processes underlying elevated CRP and/or increased CRP production itself are associated with an approximately 14% increase in population CHD risk among Indian Asians compared with European whites. CONCLUSIONS CRP concentrations are higher in healthy Indian Asians than in European whites and are accounted for by greater central obesity and insulin resistance in Indian Asians. Our results suggest that inflammation or other mechanisms underlying elevated CRP values may contribute to the increased CHD risk among Indian Asians.
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Affiliation(s)
- J C Chambers
- National Heart and Lung Institute, Imperial College School of Medicine, Hammersmith Hospital, London, UK
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Abstract
OBJECTIVE To assess the cost effectiveness of ramipril treatment in patients at low, medium, and high risk of cardiovascular death. DESIGN Population based cost effectiveness analysis from the perspective of the health care provider in the UK. Effectiveness was modelled using data from the HOPE (heart outcome prevention evaluation) trial. The life table method was used to predict mortality in a medium risk cohort, as in the HOPE trial (2.44% annual mortality), and in low and high risk groups (1% and 4.5% annual mortality, respectively). SETTING UK population using 1998 government actuary department data. MAIN OUTCOME MEASURE Cost per life year gained at five years and lifetime treatment with ramipril. RESULTS Cost effectiveness was pound36 600, pound13 600, and pound4000 per life year gained at five years and pound5300, pound1900, and pound100 per life year gained at 20 years (lifetime treatment) in low, medium, and high risk groups, respectively. Cost effectiveness at 20 years remained well below that of haemodialysis ( pound25 000 per life year gained) over a range of potential drug costs and savings. Treatment of the HOPE population would cost the UK National Health Service (NHS) an additional pound360 million but would prevent 12 000 deaths per annum. CONCLUSIONS Ramipril is cost effective treatment for cardiovascular risk reduction in patients at medium, high, and low pretreatment risk, with a cost effectiveness comparable with the use of statins. Implementation of ramipril treatment in a medium risk population would result in a major reduction in cardiovascular deaths but would increase annual NHS spending by pound360 million.
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Affiliation(s)
- I S Malik
- British Heart Foundation Cardiovascular Medicine Unit, National Heart and Lung Institute, Imperial College School of Medicine, Hammersmith Hospital, DuCane Road, London, W12 0NN, UK
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Malik IS, Bhatia VK, Kooner JS. Cost effectiveness of ramipril treatment for cardiovascular risk reduction. Heart 2001. [DOI: 10.1136/hrt.85.5.539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVETo assess the cost effectiveness of ramipril treatment in patients at low, medium, and high risk of cardiovascular death.DESIGNPopulation based cost effectiveness analysis from the perspective of the health care provider in the UK. Effectiveness was modelled using data from the HOPE (heart outcome prevention evaluation) trial. The life table method was used to predict mortality in a medium risk cohort, as in the HOPE trial (2.44% annual mortality), and in low and high risk groups (1% and 4.5% annual mortality, respectively).SETTINGUK population using 1998 government actuary department data.MAIN OUTCOME MEASURECost per life year gained at five years and lifetime treatment with ramipril.RESULTSCost effectiveness was £36 600, £13 600, and £4000 per life year gained at five years and £5300, £1900, and £100 per life year gained at 20 years (lifetime treatment) in low, medium, and high risk groups, respectively. Cost effectiveness at 20 years remained well below that of haemodialysis (£25 000 per life year gained) over a range of potential drug costs and savings. Treatment of the HOPE population would cost the UK National Health Service (NHS) an additional £360 million but would prevent 12 000 deaths per annum.CONCLUSIONSRamipril is cost effective treatment for cardiovascular risk reduction in patients at medium, high, and low pretreatment risk, with a cost effectiveness comparable with the use of statins. Implementation of ramipril treatment in a medium risk population would result in a major reduction in cardiovascular deaths but would increase annual NHS spending by £360 million.
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Abstract
CONTEXT Preeclampsia is believed to result from release of placental factors that damage maternal vascular endothelium. However, because most studies have been conducted during pregnancy, it has not been possible to separate maternal from placental mechanisms underlying endothelial dysfunction in preeclampsia. OBJECTIVE To determine whether endothelial function is impaired in nonpregnant women with previous preeclampsia and whether endothelial dysfunction is mediated by oxidative stress. DESIGN AND SETTING Case-control study conducted at 3 hospital maternity units in London, England, between July 1997 and June 2000. PARTICIPANTS A total of 113 women with previous preeclampsia (n = 35 with recurrent episodes; n = 78 with a single episode) and 48 women with previous uncomplicated pregnancies, all of whom were at least 3 months (median, 3 years) postpartum. MAIN OUTCOME MEASURES Brachial artery flow-mediated (endothelium-dependent) and glyceryl trinitrate-induced (endothelium-independent) dilatation were compared between previously preeclamptic women and controls. To investigate oxidative stress, these measurements were repeated after administration of ascorbic acid, 1 g intravenously, in 15 cases and 15 controls. RESULTS Mean (SD) flow-mediated dilatation was lower in women with previous preeclampsia compared with controls (recurrent group, 0.9% [4.1%]; single-episode group, 2.7% [3.5%]; and control group, 4.7% [4.3%]; P<.001). In contrast, glyceryl trinitrate-induced dilatation was similar in the 3 groups (recurrent, 19.5% [5.9%]; single-episode, 21.0% [8.0%]; and control, 21.0% [8.3%]; P =.65). Impaired flow-mediated dilatation in previously preeclamptic women was not accounted for by recognized vascular risk factors. Ascorbic acid administration increased flow-mediated dilatation in previously preeclamptic women (baseline, 2.6% [3.3%]; after administration, 5.6% [3.0%]; P =.001) but not in controls (baseline, 6.2% [3.3%]; after administration, 6.7% [5.0%]; P =.72). CONCLUSIONS Our results indicate that endothelial function is impaired in women with previous preeclampsia and is not explained by established maternal risk factors but is reversed by antioxidant ascorbic acid administration.
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Affiliation(s)
- J C Chambers
- National Heart and Lung Institute, Imperial College School of Medicine, Hammersmith Hospital, London, England.
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Abstract
OBJECTIVES We sought to test the hypothesis that vascular endothelial function is impaired in Behçet's syndrome and reflects increased levels of oxidative stress. BACKGROUND Behçet's syndrome is a multisystem inflammatory disorder commonly complicated by vascular thrombosis and arterial aneurysm formation. The precise mechanisms underlying vascular disease in Behçet's syndrome are not known. METHODS We studied 19 patients with Behçet's syndrome (18 to 50 years old, 9 men) and 21 healthy volunteers (18 to 50 years old, 10 men). Brachial artery flow-mediated dilation (endothelium-dependent), and nitroglycerin (NTG)-induced dilation (endothelium-independent) were measured. To investigate oxidative stress mechanisms, vascular studies were repeated 1 h after administration of vitamin C (1 g, intravenous) in 12 patients and 12 control subjects. RESULTS Flow-mediated dilation was reduced in patients with Behcet's syndrome as compared with control subjects (0.7 +/- 0.9% vs. 5.7 +/- 0.9%, p = 0.001). In contrast, there were no significant differences in the brachial artery diameter (4.2 +/- 0.2 vs. 4.0 +/- 0.2 mm, p = 0.47) or NTG-induced dilation (19.7 +/- 1.9% vs. 19.7 +/- 1.2%, p = 0.98). In regression analysis, Behçet's syndrome was associated with impaired flow-mediated dilation independent of age, gender, brachial artery diameter, blood pressure, cholesterol and glucose. Vitamin C increased flow-mediated dilation in Behçet's syndrome (0.2 +/- 0.7% to 3.5 +/- 1.0%, p = 0.002), but not in control subjects (4.3 +/- 0.6% to 4.7 +/- 0.4%, p = 0.51). In both groups, NTG-induced dilation and brachial artery diameter were unchanged after vitamin C treatment. CONCLUSIONS Vascular endothelial function is impaired in Behcet's syndrome and can be rapidly improved by vitamin C treatment. Our results support a role for oxidative stress in the pathophysiology of Behçet's syndrome and provide a rationale for therapeutic studies aimed at reducing vascular complications in this disorder.
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Affiliation(s)
- J C Chambers
- National Heart and Lung Institute, Imperial College School of Medicine, Hammersmith Hospital, London, United Kingdom
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Affiliation(s)
- J C Chambers
- National Heart and Lung Institute, Imperial College School of Medicine, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
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Chambers JC, Ueland PM, Obeid OA, Wrigley J, Refsum H, Kooner JS. Improved vascular endothelial function after oral B vitamins: An effect mediated through reduced concentrations of free plasma homocysteine. Circulation 2000; 102:2479-83. [PMID: 11076820 DOI: 10.1161/01.cir.102.20.2479] [Citation(s) in RCA: 172] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Hyperhomocysteinemia is an independent risk factor for coronary heart disease (CHD). Dietary supplementation with B vitamins lowers plasma homocysteine by up to 30%. However, little is known about the potential beneficial effects of homocysteine lowering on vascular function in patients with CHD. METHODS AND RESULTS We investigated 89 men with CHD (aged 56 [range 39 to 67] years). Brachial artery flow-mediated dilatation (endothelium dependent) and nitroglycerin-induced dilatation (endothelium independent) were measured before and 8 weeks after treatment with either (1) folic acid (5 mg) and vitamin B(12) (1 mg) daily (n=59) or (2) placebo (n=30). Total, protein-bound, and free plasma homocysteine, serum folate, and vitamin B(12) were measured at baseline and at 8 weeks. Flow-mediated dilatation improved after treatment with B vitamins (2.5+/-3.2% to 4.0+/-3.7%, P:=0.002) but not placebo (2.3+/-2.6% to 1.9+/-2.6%, P:=0.5). Vitamin therapy lowered plasma concentrations of total homocysteine (from 13.0+/-3.4 to 9.3+/-1.9 micromol/L, P:<0.001), protein-bound homocysteine (from 8.7+/-2.8 to 6.2+/-1.4 micromol/L, P:<0.001), and free homocysteine (from 4.3+/-1.2 to 3.0+/-0.6 micromol/L, P:<0.001) and raised concentrations of serum folate (from 10.3+/-4.3 to 31.2+/-10.8 ng/mL, P:<0.001) and vitamin B(12) (from 314+/-102 to 661+/-297 pg/mL, P:<0.001). In regression analysis, improved flow-mediated dilatation correlated closely with the reduction in free plasma homocysteine (r=-0.26, P:=0.001), independent of changes in protein-bound homocysteine, folate, and vitamin B(12). Nitroglycerin-induced dilatation was unchanged after both B vitamins and placebo. CONCLUSIONS Folic acid and vitamin B(12) supplementation improves vascular endothelial function in patients with CHD, and this effect is likely to be mediated through reduced concentrations of free plasma homocysteine concentrations. Our data support the view that lowering homocysteine, through B vitamin supplementation, may reduce cardiovascular risk.
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Affiliation(s)
- J C Chambers
- National Heart and Lung Institute, Imperial College School of Medicine, Hammersmith Hospital, London, UK
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Chambers JC, Wander GS, Kooner JS. Homocysteine and coronary heart disease amongst Indian Asians. Indian Heart J 2000; 52:S5-8. [PMID: 11339441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023] Open
Affiliation(s)
- J C Chambers
- National Heart and Lung Institute, Imperial College School of Medicine, Hammersmith Hospital, London, UK
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Chambers JC, Ireland H, Thompson E, Reilly P, Obeid OA, Refsum H, Ueland P, Lane DA, Kooner JS. Methylenetetrahydrofolate reductase 677 C-->T mutation and coronary heart disease risk in UK Indian Asians. Arterioscler Thromb Vasc Biol 2000; 20:2448-52. [PMID: 11073851 DOI: 10.1161/01.atv.20.11.2448] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Plasma homocysteine concentrations are elevated in UK Indian Asians and may contribute to twice as many coronary heart disease (CHD) deaths in this group compared with European whites. The mechanisms underlying elevated homocysteine concentrations among Indian Asians are not well understood. In this study, we have investigated the extent to which the methylenetetrahydrofolate reductase (MTHFR) 677 C-->T mutation accounts for elevated plasma homocysteine and increased CHD risk in Indian Asians compared with European whites. We investigated 454 male cases (with myocardial infarction or angiographically proven CHD: 224 Indian Asians, 230 European whites) and 805 healthy male controls (381 Indian Asians, 424 European whites). Fasting homocysteine concentrations, MTHFR 677 C-->T genotype, and conventional CHD risk factors were measured. The prevalence of homozygous MTHFR 677T in Indian Asian controls was less than one third that in European white controls (3.1% versus 9. 7%, P<0.001). In Indian Asians, the TT MTHFR genotype was not associated with homocysteine concentrations and was not present in any of the Asian controls with hyperhomocysteinemia (>15 micromol/L). In contrast, among European whites, the TT MTHFR genotype was strongly related to elevated plasma homocysteine concentrations and was found in 27% of the European controls with hyperhomocysteinemia. Elevated homocysteine in Indian Asian compared with European white controls was accounted for by their reduced levels of B vitamins but not by the MTHFR 677T genotype. However, neither the TT MTHFR genotype nor B vitamin levels explained the elevated homocysteine concentrations in CHD cases compared with controls. TT MTHFR was not a risk factor for early-onset CHD in Indian Asians (odds ratio, 0.5; 95% confidence interval, 0.1 to 2.4; P=0.39), unlike in European whites (odds ratio, 2.1; 95% confidence interval, 1.1 to 4. 1; P=0.02). We conclude that the MTHFR 677T: mutation does not contribute to elevated plasma homocysteine concentrations or increased CHD risk in Indian Asians compared with European whites. Our results suggest that novel genetic defects and/or environmental factors influence homocysteine metabolism in Indian Asians residing in the United Kingdom.
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Affiliation(s)
- J C Chambers
- National Heart and Lung Institute, Imperial College School of Medicine, Hammersmith Hospital, London, UK
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Chambers JC, Obeid OA, Refsum H, Ueland P, Hackett D, Hooper J, Turner RM, Thompson SG, Kooner JS. Plasma homocysteine concentrations and risk of coronary heart disease in UK Indian Asian and European men. Lancet 2000; 355:523-7. [PMID: 10683001 DOI: 10.1016/s0140-6736(99)93019-2] [Citation(s) in RCA: 179] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Reasons for the increase in mortality due to coronary heart disease (CHD) in UK Indian Asians are not well understood. In this study, we tested the hypotheses that elevated plasma homocysteine concentrations are a risk factor for CHD in Indian Asians, and explain part of their increased CHD risk, compared with Europeans. METHODS We undertook two parallel case-control studies, one in Europeans and one in Indian Asians. We recruited 551 male cases (294 European, 257 Indian Asian) and 1025 healthy male controls (507 European, 518 Indian Asian). Fasting and post-methionine load homocysteine, vitamin B12 and folate concentrations, and conventional CHD risk factors were measured. FINDINGS Fasting homocysteine concentrations were 8% higher (95% CI 3-14) in cases compared with controls, in both ethnic groups. The odds ratio of CHD for a 5 micromol/L increment in fasting plasma homocysteine was 1.3 (1.1-1.6) in Europeans and 1.2 (1.0-1.4) in Indian Asians. The association between fasting plasma homocysteine and CHD was independent of conventional CHD risk factors in both ethnic groups. Post-load homocysteine concentrations were not significantly different in cases compared with controls. Among the controls, fasting homocysteine concentrations were 6% (2-10) higher in Indian Asians than in Europeans. From the results we estimate that elevated homocysteine may contribute to twice as many CHD deaths in Indian Asians, compared with Europeans. The differences in homocysteine concentrations between the two ethnic groups were explained by lower vitamin B12 and folate levels in Asians. INTERPRETATION Plasma homocysteine is a novel and independent risk factor for CHD in Indian Asians, and may contribute to their increased CHD risk. Raised homocysteine concentrations in Indian Asians may be related to their reduced vitamin B12 and folate levels, implying that the increased CHD risk in this group may be reduced by dietary vitamin supplementation.
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Affiliation(s)
- J C Chambers
- National Heart and Lung Institute, Imperial College School of Medicine, Hammersmith Hospital, London
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Chambers JC, Obeid OA, Kooner JS. Physiological increments in plasma homocysteine induce vascular endothelial dysfunction in normal human subjects. Arterioscler Thromb Vasc Biol 1999; 19:2922-7. [PMID: 10591670 DOI: 10.1161/01.atv.19.12.2922] [Citation(s) in RCA: 117] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We hypothesized that physiological increments in plasma homocysteine after low-dose oral methionine or dietary animal protein induce vascular endothelial dysfunction and that there is a graded, inverse relationship between homocysteine concentration and endothelial function. We studied 18 healthy volunteers aged 18 to 59 years. Brachial artery flow-mediated and glyceryltrinitrate-induced dilatation were measured after 1) oral L-methionine (10, 25, and 100 mg/kg), 2) dietary animal protein (lean chicken 551+/-30 g, comprising 3.2+/-0.2 g methionine), and 3) methionine-free amino acid mix (100 mg/kg). Methionine (10, 25, and 100 mg/kg) induced a dose-related increase in homocysteine (9.4+/-1.3 to 12.2+/-2.1, 17. 6+/-2.6, and 26.1+/-4.2 micromol/L, respectively; P<0.001) and a reduction in flow-mediated dilatation (4.1+/-0.8 to 2.1+/-0.8, 0. 3+/-0.8, and -0.7+/-0.8%, respectively; P<0.001) at 4 hours. Compared with usual meal, animal protein increased plasma homocysteine (9.6+/-0.8 to 11.2+/-0.9 micromol/L, P=0.005) and reduced flow-mediated dilatation (4.5+/-0.7% to 0.9+/-0.6%, P=0.003). Methionine-free amino acid mix did not induce any changes. Glyceryltrinitrate-induced dilatation was unchanged throughout. In this study, small physiological increments in plasma homocysteine after low-dose methionine and dietary animal protein induced vascular endothelial dysfunction. We propose that protein intake-induced increments in plasma homocysteine may have deleterious effects on vascular function and contribute to the development and progression of atherosclerosis.
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Affiliation(s)
- J C Chambers
- National Heart and Lung Institute, Imperial College School of Medicine, Hammersmith Hospital, London, UK
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Chambers JC, McGregor A, Jean-Marie J, Kooner JS. Abnormalities of vascular endothelial function may contribute to increased coronary heart disease risk in UK Indian Asians. Heart 1999; 81:501-4. [PMID: 10212168 PMCID: PMC1729047 DOI: 10.1136/hrt.81.5.501] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE To test the hypothesis that abnormalities of endothelial function are present in Indian Asians and may contribute to their increased coronary heart disease risk. SETTING Single centre in west London. PATIENTS 26 Indian Asian and 18 European white healthy male subjects, aged 35 to 61 years recruited from general practice lists. DESIGN Brachial artery diameter responses to reactive hyperaemia and sublingual glyceryl trinitrate were compared using high resolution ultrasound. RESULTS Mean (SEM) flow mediated, endothelium dependent dilatation was reduced in Indian Asians compared with European whites, at 3.2 (0.8)% v 5.9 (1.0)%, p = 0.03. In contrast, there were no significant differences in baseline brachial arterial diameter (4.6 (0.1) v 4.6 (0.1) mm, p = 0.65) or glyceryl trinitrate induced dilatation (18.8 (1.5)% v 18.5 (1.7)%, p = 0.90) between Indian Asians and European whites, respectively. Univariate analysis showed that Indian Asian race was significantly associated with impaired flow mediated dilatation (regression coefficient = -2.8 (1.3)%, p = 0.03), and in multivariate analysis, this relation was independent of both conventional coronary heart disease risk factors and markers of insulin resistance. CONCLUSIONS Endothelial function is impaired in healthy UK Indian Asians compared with European whites, and the defect is not accounted for by major coronary heart disease risk factors. Endothelial function may be modulated by novel risk factors in Indian Asians.
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Affiliation(s)
- J C Chambers
- National Heart and Lung Institute, Imperial College School of Medicine, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
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Chambers JC, McGregor A, Jean-Marie J, Obeid OA, Kooner JS. Demonstration of rapid onset vascular endothelial dysfunction after hyperhomocysteinemia: an effect reversible with vitamin C therapy. Circulation 1999; 99:1156-60. [PMID: 10069782 DOI: 10.1161/01.cir.99.9.1156] [Citation(s) in RCA: 282] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Hyperhomocysteinemia is a major and independent risk factor for vascular disease. The mechanisms by which homocysteine promotes atherosclerosis are not well understood. We hypothesized that elevated homocysteine concentrations are associated with rapid onset endothelial dysfunction, which is mediated through oxidant stress mechanisms and can be inhibited by the antioxidant vitamin C. METHODS AND RESULTS We studied 17 healthy volunteers (10 male and 7 female) aged 33 (range 21 to 59) years. Brachial artery diameter responses to hyperemic flow (endothelium dependent), and glyceryltrinitrate (GTN, endothelium independent) were measured with high resolution ultrasound at 0 hours (fasting), 2 hours, and 4 hours after (1) oral methionine (L-methionine 100 mg/kg), (2) oral methionine preceded by vitamin C (1g/day, for 1 week), and (3) placebo, on separate days and in random order. Plasma homocysteine increased (0 hours, 12.8+/-1.4; 2 hours, 25.4+/-2.5; and 4 hours, 31. 2+/-3.1 micromol/l, P<0.001), and flow-mediated dilatation fell (0 hours, 4.3+/-0.7; 2 hours, 1.1+/-0.9; and 4 hours, -0.7+/-0.8%) after oral L-methionine. There was an inverse linear relationship between homocysteine concentration and flow-mediated dilatation (P<0. 001). Pretreatment with vitamin C did not affect the rise in homocysteine concentrations after methionine (0 hours, 13.6+/-1.6; 2 hours, 28.3+/-2.9; and 4 hours, 33.8+/-3.7 micromol/l, P=0.27), but did ameliorate the reduction in flow-mediated dilatation (0 hours, 4. 0+/-1.0; 2 hours, 3.5+/-1.2 and 4 hours, 2.8+/-0.7%, P=0.02). GTN-induced endothelium independent brachial artery dilatation was not affected after methionine or methionine preceded by vitamin C. CONCLUSIONS We conclude that an elevation in homocysteine concentration is associated with an acute impairment of vascular endothelial function that can be prevented by pretreatment with vitamin C in healthy subjects. Our results support the hypothesis that the adverse effects of homocysteine on vascular endothelial cells are mediated through oxidative stress mechanisms.
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Affiliation(s)
- J C Chambers
- National Heart and Lung Institute, Imperial College School of Medicine, Hammersmith Hospital, London, UK
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Hermansen F, Ashburner J, Spinks TJ, Kooner JS, Camici PG, Lammertsma AA. Generation of myocardial factor images directly from the dynamic oxygen-15-water scan without use of an oxygen-15-carbon monoxide blood-pool scan. J Nucl Med 1998; 39:1696-702. [PMID: 9776271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023] Open
Abstract
UNLABELLED The measurement of regional myocardial blood flow (MBF) with H2(15)O and PET requires an additional C15O blood-pool scan for the purpose of region of interest (ROI) definition. This additional scan results in a substantially increased radiation dose, study duration and risk of movement artifacts. Therefore, a method was developed to generate myocardial factor images directly from the dynamic H2(15)O study without the need for a C15O scan. METHODS The factor sinograms were generated by means of linear dimension reduction of the dynamic sinograms, where the required variate and covariate factors (myocardial and blood time-activity curves) were modeled from the lung time-activity curve. The factor images were generated by iterative reconstruction. RESULTS No significant difference was found between MBF values from ROIs drawn on the traditional images (using the C15O scan) and those drawn on the factor images. CONCLUSION It is possible to generate myocardial images directly from the dynamic H2(15)O study, so that the C15O scan can be omitted from MBF studies. The proposed method is robust and results in nearly optimal signal-to-noise ratios in the factor images.
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Affiliation(s)
- F Hermansen
- Cyclotron Unit, MRC Clinical Sciences Centre, Hammersmith Hospital, London, United Kingdom
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Hermansen F, Rosen SD, Fath-Ordoubadi F, Kooner JS, Clark JC, Camici PG, Lammertsma AA. Measurement of myocardial blood flow with oxygen-15 labelled water: comparison of different administration protocols. Eur J Nucl Med 1998; 25:751-9. [PMID: 9662598 DOI: 10.1007/s002590050279] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Positron emission tomography (PET) in conjunction with C15O2 or H215O can be used to measure myocardial blood flow (MBF) and tissue fraction (TF), i.e. the fraction of the tissue mass in the volume of the region of interest. However, with C15O2 inhalation, the tissue fraction in the septum is overestimated. Bolus injection of H215O together with arterial cannulation gives very precise results but is invasive. The purpose of this study was to develop a method which circumvents these problems. A four-parameter model with parameters for MBF, TF and spill-over fractions from both left and right ventricular cavities was developed. This method was compared with a three-parameter model (no right ventricular cavity spill-over) in both septal and non-septal regions of interest for three different administration protocols: bolus injection of H215O, infusion of H215O and inhalation of C15O2. It was found that MBF can be measured with intravenous administration of H215O without the requirement for arterial cannulation. The four-parameter protocol with bolus injection was stable in clinical studies. The four-parameter model proved essential for the septum, where it gave highly significantly better fits than did the three-parameter model (P<0.00003 in each of 15 subjects). Administration of H215O together with this four-parameter model also circumvented the problem of overestimation of TF in the septum seen with C15O2 inhalation. In addition, the radiation dose of H215O protocols is lower than that of C15O2 inhalation. Using a left atrial input curve instead of a left ventricular cavity input curve gave the same mean MBF and TF.
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Affiliation(s)
- F Hermansen
- PET Methodology and Cardiology Groups, MRC Cyclotron Unit, Imperial College School of Medicine, Hammersmith Hospital, London, UK
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Kooner JS, Baliga RR, Wilding J, Crook D, Packard CJ, Banks LM, Peart S, Aitman TJ, Scott J. Abdominal obesity, impaired nonesterified fatty acid suppression, and insulin-mediated glucose disposal are early metabolic abnormalities in families with premature myocardial infarction. Arterioscler Thromb Vasc Biol 1998; 18:1021-6. [PMID: 9672061 DOI: 10.1161/01.atv.18.7.1021] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
British Indian Asian men aged <40 years have a twofold to threefold increased risk of death from coronary heart disease (CHD) compared with British whites. Epidemiological studies have suggested an association between glucose intolerance and hyperinsulinemia with premature CHD in Indian Asians. We tested the association of insulin action with myocardial infarction (MI) by using the hyperinsulinemic-euglycemic clamp in 17 MI patients: 8 Punjabi Sikhs (PSMIs), 9 British whites (BWMIs), and 17 control subjects (9 PSCs and 8 BWCs). Metabolic factors associated with insulin resistance were investigated in 51 MI patients (24 PSMIs and 27 BWMIs) and 53 control subjects (28 PSCs and 25 BWCs). Familial aggregation of defective insulin action was examined by studying five pedigrees of Sikh survivors of MI. Sikh survivors of premature MI demonstrated impaired insulin-mediated glucose uptake (P<.001) by use of the clamp technique and nonesterified fatty acid (NEFA) suppression (P<.05) by using both clamp techniques and the oral glucose tolerance test, as compared with Sikh control subjects. White patients had impaired insulin-mediated glucose uptake but normal NEFA suppression. Metabolic factors usually associated with insulin resistance, including increased 2-hour post-oral glucose tolerance test triglycerides, smaller low density lipoprotein particle size, and increased plasminogen activator inhibitor-1, were present in white (all P<.05) but surprisingly absent in Sikh (all P>.05) MI patients compared with respective ethnic control subjects. Fasting glucose and total cholesterol levels did not differ between patients and control subjects. Abdominal obesity, impaired NEFA suppression after oral glucose, and fasting hyperinsulinemia were present in Sikh MI patients and their nondiabetic first-degree relatives compared with Sikh control subjects. PS survivors of premature MI demonstrated impaired insulin-mediated glucose disposal and NEFA suppression compared with ethnic control subjects. BWMI patients showed abnormalities of carbohydrate, but not of NEFA, metabolism compared with white control subjects. Defects of insulin action manifested as abdominal obesity, impaired NEFA suppression, and fasting hyperinsulinemia are present in Sikh MI patients and their asymptomatic, nondiabetic, first-degree relatives. We suggest that these defects may be early metabolic markers that predict risk of premature MI among PSs.
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Affiliation(s)
- J S Kooner
- Department of Medicine, Royal Postgraduate Medical School, Hammersmith Hospital, London, UK
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Abstract
BACKGROUND Postprandial angina pectoris has been recognized for more than two centuries and can be identified in up to 10% of patients with chronic ischemic heart disease. Redistribution of myocardial blood flow, from a region supplied by a severely stenotic coronary artery to those supplied by less diseased or normal vessels, is a potential mechanism of postprandial angina. METHODS AND RESULTS To test this hypothesis, we have determined the effects of a standard liquid meal on whole heart and regional myocardial blood flow, measured by means of dynamic positron emission tomography (PET) with 15O-labeled water in 14 patients with a reproducible history of postprandial angina and 7 matched control subjects. The standard liquid meal precipitated angina pectoris in all patients. Baseline whole heart blood flow was similar and increased normally after the meal in patients (0.97+/-0.14 to 1.14+/-0.25 mL.min(-1).g(-1), P<.04) as in control subjects (0.92+/-0.12 to 1.02+/-0.13 mL.min(-1).g(-1), P<.02). In contrast, the coefficient of variation of blood flow increased significantly after the standard liquid meal in patients (34+/-9%, P<.05 versus baseline) but not in control subjects (17+/-7%, P=NS versus baseline). In patients, analysis of regional myocardial blood flow demonstrated decreased myocardial blood flow in territories supplied by stenotic arteries (1.01+/-0.35 to 0.76+/-0.27 mL.min(-1).g(-1), P<.03), but there was an increase in blood flow in territories supplied by normal arteries (0.89+/-0.16 to 1.34+/-0.25 mL.min(-1).g(-1), P<.001) after the meal. CONCLUSIONS The standard liquid meal induced angina pectoris in patients with coronary artery disease. Although whole heart blood flow increased appropriately for the greater cardiac work, there was a redistribution of regional blood flow from territories supplied by severely stenosed coronary arteries to those supplied by less diseased or normal arteries. This redistribution may be the cause of myocardial ischemia in postprandial angina.
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Affiliation(s)
- R R Baliga
- National Heart and Lung Institute, Imperial College School of Medicine, Hammersmith Hospital, London, UK
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Abstract
The pressor and vasoconstrictor action of angiotensin II (ANG II) is considered to be caused by a combination of its direct and indirect vascular effects, the latter mediated by the sympathetic nervous system. The purpose of this study was to determine the extent to which the direct and indirect actions of ANG II contribute to its pressor and vascular effects. Blood pressure, cutaneous vascular, and plasma norepinephrine responses to intravenous ANG II were measured in conscious rabbits before and after inhibition of central sympathetic outflow with intravenous and intracisternal clonidine and after ganglionic blockade with intravenous pentolinium. Intravenous ANG II caused a similar dose-related rise in blood pressure before and after sympathetic blockade with intravenous clonidine, intracisternal clonidine, and intravenous pentolinium. In contrast, the dose-related fall in cutaneous ear blood flow and cutaneous ear temperature and rise in cutaneous ear vascular resistance induced by intravenous ANG II were abolished after intravenous clonidine, intracisternal clonidine, and intravenous pentolinium. Heart rate was unchanged after ANG II. There were no changes in back skin or rectal temperature. There was a nonsignificant fall in plasma norepinephrine and no change in epinephrine after ANG II. These results demonstrate that the acute pressor response to intravenous ANG II is mediated by its direct vascular effects and is not dependent on central or ganglionic stimulation of the sympathetic nervous system, in contrast to the effect of ANG II on cutaneous ear vasoconstriction, which is predominantly caused by a centrally mediated increase in sympathetic nervous activity. Our results separate, in conscious rabbits, the direct vascular effects of ANG II from its indirect vascular actions, which are mediated by central sympathetic stimulation in the brain.
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Affiliation(s)
- J S Kooner
- Department of Medicine, Royal Postgraduate Medical School, Hammersmith Hospital, London, United Kingdom
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Abstract
Though calcium plays an important role in a number of biologic processes related to the pathogenesis of atherosclerosis, the relationship of serum calcium and phosphorus levels with the angiographic severity of coronary artery disease (CAD) is not known. We retrospectively studied 376 stable patients (age range 31-86 years, mean 59.2 +/- 10.5 years; 68% males) undergoing routine coronary angiography and related the angiographic severity of CAD with the serum levels of total and corrected calcium, phosphorus, albumin, total protein and bicarbonate. The primary variable studied was the number of vessels with haemodynamically significant disease. On univariate analysis, total serum calcium and serum albumin levels had a negative association with the number of vessels diseased (P = 0.046 and 0.057, respectively). Multiple regression analysis using age, sex, smoking, diabetes, hypertension, hyperlipidaemia, ethnicity and family history, in addition to serum calcium, phosphorus and albumin levels as the predictor variables, showed that serum albumin has an independent negative and serum phosphorus has an independent positive association with the angiographic severity of CAD (P = 0.04 and 0.003, respectively; n = 294). Serum phosphorus level also showed highly significant positive associations with the presence of total or subtotal occlusion and with most severe stenosis observed on angiography. A moderate change in the serum level of albumin or phosphorus confers a risk similar to that associated with smoking, as estimated by the odds ratios.
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Affiliation(s)
- R Narang
- Department of Cardiology, Hammersmith Hospital, London, UK
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Baliga RR, Burden L, Sidhu MK, Rampling MW, Kooner JS. Effects of components of meals (carbohydrate, fat, protein) in causing postprandial exertional angina pectoris. Am J Cardiol 1997; 79:1397-400. [PMID: 9165167 DOI: 10.1016/s0002-9149(97)00149-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We have shown that unlike fat, protein, xylose, or water, the carbohydrate component of the meal accelerates myocardial ischemia, reduces exercise capacity, and is associated with a more rapid increase in the determinants of myocardial oxygen consumption than exercise in the fasting state. Our results suggest a role for a larger increase in sympathetic nervous activity and/or release of vasoactive gastrointestinal peptides after carbohydrate, but not fat or protein, meals in postprandial angina.
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Affiliation(s)
- R R Baliga
- Department of Medicine, Royal Postgraduate Medical School, Hammersmith Hospital, London, United Kingdom
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Paternostro G, Camici PG, Lammerstma AA, Marinho N, Baliga RR, Kooner JS, Radda GK, Ferrannini E. Cardiac and skeletal muscle insulin resistance in patients with coronary heart disease. A study with positron emission tomography. J Clin Invest 1996; 98:2094-9. [PMID: 8903329 PMCID: PMC507654 DOI: 10.1172/jci119015] [Citation(s) in RCA: 112] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Patients with coronary artery disease or heart failure have been shown to be insulin resistant. Whether in these patients heart muscle participates in the insulin resistance, and whether reduced blood flow is a mechanism for such resistance is not known. We measured heart and skeletal muscle blood flow and glucose uptake during euglycemic hyperinsulinemia (insulin clamp) in 15 male patients with angiographically proven coronary artery disease and chronic regional wall motion abnormalities. Six age- and weight-matched healthy subjects served as controls. Regional glucose uptake was measured by positron emission tomography using [18F]2-fluoro-2-deoxy-D-glucose (FDG), blood flow was measured by the H2(15)O method. Myocardial glucose utilization was measured in regions with normal perfusion and wall motion as assessed by radionuclide ventriculography. Whole-body glucose uptake was 37+/-4 micromol x min(-1) x kg(-1) in controls and 14+/-2 mciromol x min(-1) x kg(-1) in patients (P = 0.001). Myocardial blood flow (1.09+/-0.06 vs. 0.97+/-0.04 ml x min(-1) x g(-1), controls vs. patients) and skeletal muscle (arm) blood flow (0.046+/-0.012 vs. 0.043+/-0.006 ml x min(-1) x g(-1)) were similar in the two groups (P = NS for both). In contrast, in patients both myocardial (0.38+/-0.03 vs. 0.70+/-0.03 micromol x min(-1) x g(-1), P = 0.0005) and muscle glucose uptake (0.026+/-0.004 vs. 0.056+/-0.006 micromol x min(-1) x g(-1), P = 0.005) were markedly reduced in comparison with controls. In the whole dataset, a direct relationship existed between insulin-stimulated glucose uptake in heart and skeletal muscle. Patients with a history of myocardial infarction and a low ejection fraction are insulin resistant. This insulin resistance affects both the myocardium and skeletal muscle and is independent of blood flow.
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Affiliation(s)
- G Paternostro
- Royal Postgraduate Medical School, Hammersmith Hospital, London, United Kingdom
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41
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Abstract
The contribution of neurogenic mechanisms in maintaining hypertension was investigated in 13 patients with unilateral renal artery stenosis (twelve with normal, one with grossly elevated plasma renin levels) by determining the haemodynamic and hormonal responses to the centrally acting sympatholytic agent, clonidine. The same patients were studied after captopril to determine the dependency of their blood pressure on the direct peripheral effects of angiotensin-II. Sixteen patients with essential hypertension (normal plasma renin) were additionally studied after clonidine. After clonidine, blood pressure fell markedly in patients with renal artery stenosis (17 +/- 3%) and essential hypertension (18 +/- 2%). In both groups, clonidine lowered cardiac output by a reduction in stroke volume and heart rate; forearm vascular resistance was unchanged but digital skin vascular resistance fell. Plasma noradrenaline levels were normal in both groups and fell after clonidine; plasma renin activity and aldosterone levels were unchanged. After captopril, blood pressure fell minimally (5 +/- 3%) in renal artery stenosis patients; cardiac output fell and forearm and digital skin vascular resistance were unchanged. Plasma renin activity rose, plasma aldosterone fell and plasma noradrenaline was unchanged after captopril. In the patient with grossly elevated renin levels, blood pressure fell minimally (6%) after clonidine, but unlike others fell profoundly (37%) after captopril. We conclude that, in the majority of our renal artery stenosis patients, despite the elevated blood pressure, sympathetic nervous activity was not reduced. Central neurogenic mechanisms appear to play an important role in maintaining raised blood pressure. In the same patients the peripheral effects of angiotensin-II did not maintain vascular tone or hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J S Kooner
- Department of Medicine, St Mary's Hospital Medical School/Imperial College, London, UK
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Kooner JS, Birch R, Frankel HL, Peart WS, Mathias CJ. Hemodynamic and neurohormonal effects of clonidine in patients with preganglionic and postganglionic sympathetic lesions. Evidence for a central sympatholytic action. Circulation 1991; 84:75-83. [PMID: 2060125 DOI: 10.1161/01.cir.84.1.75] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND Clonidine, a partial presynaptic and postsynaptic alpha-adrenoceptor agonist, has been shown to lower blood pressure in normal subjects but not in tetraplegics; however, the mechanisms of this action have not been elucidated. METHODS AND RESULTS The hemodynamic and hormonal basis of the hypotensive action of clonidine was investigated in tetraplegics with complete cervical spinal cord transection and preganglionic sympathetic denervation, in patients with unilateral brachial plexus injury and postganglionic sympathetic denervation, and in normal subjects. In normal subjects, the fall in blood pressure after clonidine infusion was accompanied by a reduction in cardiac output that was predominantly due to a fall in stroke volume and in heart rate. The lack of fall in blood pressure, cardiac output, and stroke volume in tetraplegics indicates that these effects are exerted at a supraspinal level and require intact descending sympathetic pathways. After clonidine infusion, digital skin vasodilatation occurred in normal subjects, in the innervated but not the denervated limb of patients with unilateral brachial plexus injury, and in tetraplegics, indicating that this response is due to the central sympatholytic effect of clonidine. Plasma norepinephrine was much lower in tetraplegics compared with normal subjects, and after clonidine infusion, it fell substantially in normal subjects alone. Plasma renin activity did not change. Bladder stimulation in tetraplegics resulted in a rise in blood pressure and vasoconstriction in digital skin vessels. The inability of clonidine to significantly reduce or abolish the pressor and digital vasoconstrictor responses after bladder stimulation in tetraplegics indicates that clonidine does not exert a major effect on spinal preganglionic neurons or peripheral presynaptic alpha 2-adrenoceptors. CONCLUSIONS Therefore, clonidine is a suitable drug for use in analyzing the central supraspinal levels of control in varying circulatory disorders, such as hypertension and postural hypotension.
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Affiliation(s)
- J S Kooner
- Department of Medicine, St. Mary's Hospital, London, UK
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Abstract
A method for the direct determination of 18-hydroxycorticosterone (18OHB) in human saliva has been developed and validated. Saliva was collected at 30 min and 1 h intervals between 0600 and 2200 h from healthy men and women for the determination of 18OHB (SHB), aldosterone (SA) and glucocorticoids (SGC = cortisol + cortisone). SHB was highly correlated with SA (r = 0.75; P less than 0.001) but even more highly with SGC (r = 0.89; P greater than 0.001). Multiple regression analysis confirmed that SGC was a more important determinant of SHB than was SA. Though the concentrations of 18OHB and aldosterone were highly correlated there was considerable variation in the 18OHB:aldosterone ratio during the period of saliva collection. This ratio tended to be highest in the morning and lowest in the evening and was weakly correlated with SGC level (r = 0.62; P less than 0.01). The 18OHB:aldosterone ratio in saliva approximates to, and is highly correlated with, that in plasma. We suggest that the fluctuations in SHB:SA ratio correspond to the relative rates of secretion of 18OHB and aldosterone and that this ratio is modulated either by ACTH or by cortisol. Whether this indicates that 18OHB is a by-product of glucocorticoid as well as aldosterone metabolism, or whether this implies a separate physiological role for the steroid remains to be clarified.
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Affiliation(s)
- J S Kooner
- Cardiovascular Research Unit, Hammersmith Hospital, London, England
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Raimbach SJ, Cortelli P, Kooner JS, Bannister R, Bloom SR, Mathias CJ. Prevention of glucose-induced hypotension by the somatostatin analogue octreotide (SMS 201-995) in chronic autonomic failure: haemodynamic and hormonal changes. Clin Sci (Lond) 1989; 77:623-8. [PMID: 2691174 DOI: 10.1042/cs0770623] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
1. The haemodynamic and hormonal changes following glucose ingestion (1 g/kg) were determined before and after pretreatment with either placebo or the somatostatin analogue, octreotide (SMS 201-995, 50 micrograms subcutaneously), in seven patients with chronic autonomic failure. 2. In the placebo phase, after glucose, there was a marked and prolonged fall in blood pressure with no change in cardiac index and peripheral blood flow. Plasma insulin and neurotensin levels increased, whereas glucagon, vasoactive intestinal polypeptide, noradrenaline and adrenaline levels were unchanged. 3. Octreotide transiently raised blood pressure and prevented glucose-induced hypotension. There were no changes in cardiac index or peripheral blood flow. Plasma insulin and neurotensin levels did not rise. Plasma glucose levels increased more slowly but reached a similar level to the placebo phase. 4. We conclude that in autonomic failure patients, glucose-induced hypotension was not accompanied by changes in cardiac index or peripheral blood flow, indicating a lack of compensation to probable splanchnic vasodilatation. The hypotension was prevented by the peptide release inhibitor, octreotide, with no change in cardiac index or in peripheral blood flow, suggesting an effect on the splanchnic vasculature, probably through inhibiting release of vasodilatatory pancreatic and gut peptides.
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Affiliation(s)
- S J Raimbach
- Department of Medicine, St Mary's Hospital Medical School, University Department of Clinical Neurology, London
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Kooner JS, Raimbach S, Bannister R, Peart S, Mathias CJ. Angiotensin converting enzyme inhibition lowers blood pressure in patients with primary autonomic failure independently of plasma renin levels and sympathetic nervous activity. J Hypertens Suppl 1989; 7:S42-3. [PMID: 2698948 DOI: 10.1097/00004872-198900076-00018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The haemodynamic and neurohormonal responses to the angiotensin converting enzyme (ACE) inhibitor captopril were studied in 12 patients with primary autonomic failure; seven had multiple system atrophy and five had pure autonomic failure. Basal supine mean arterial blood pressure was higher in the patients with multiple system atrophy than in those with pure autonomic failure and the normal subjects. Basal plasma noradrenaline levels were normal in the patients with multiple system atrophy, but lower in those with pure autonomic failure. Captopril lowered the mean arterial pressure in the patients with multiple system atrophy and pure autonomic failure but not in the normal subjects. In the patients with multiple system atrophy and pure autonomic failure, captopril lowered the cardiac output and the stroke volume. Forearm vascular resistance was unchanged. No significant changes occurred in the normal subjects. Plasma renin activity was unchanged after captopril in the patients with autonomic failure, but rose in the normal subjects. Plasma noradrenaline was unchanged in all groups after the administration of captopril. We conclude that captopril lowers the mean arterial pressure in patients with multiple system atrophy and pure autonomic failure. After the administration of captopril there is a reduction in cardiac output, secondary to a fall in stroke volume. The vasodepressor response to captopril in patients with autonomic failure is not related to the basal level of plasma renin activity or sympathetic nervous activity, indicating that the hypotensive effects of bradykinin or prostaglandins, or both, may contribute.
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Affiliation(s)
- J S Kooner
- Department of Medicine, St Mary's Hospital Medical School, Queen Square, London, UK
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Kooner JS, Raimbach S, Watson L, Bannister R, Peart S, Mathias CJ. Relationship between splanchnic vasodilation and postprandial hypotension in patients with primary autonomic failure. J Hypertens Suppl 1989; 7:S40-1. [PMID: 2632742 DOI: 10.1097/00004872-198900076-00017] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The haemodynamic responses to a standard liquid meal were measured in patients with autonomic failure and in normal subjects. Resting superior mesenteric artery blood flow was similar in both groups, but mean supine arterial pressure and the superior mesenteric artery vascular resistance were higher in the patients with autonomic failure than in the normal subjects. After the meal there was a rise in superior mesenteric artery blood flow and a fall in superior mesenteric artery vascular resistance in both groups. Mean arterial blood pressure fell substantially after food in the patients with autonomic failure but not in the normal subjects. The basal heart rate, stroke distance and cardiac index were higher in the patients with autonomic failure, and rose significantly after the meal only in the normal subjects. Forearm blood flow fell and the vascular resistance rose after the meal in the normal subjects but not in the patients with autonomic failure. We conclude that superior mesenteric artery blood flow rose and superior mesenteric artery vascular resistance fell after the meal in the normal subjects and in the patients with autonomic failure. However, in the normal subjects the blood pressure was maintained by factors which include a rise in the heart rate and cardiac output. The lack of such compensatory changes probably accounts for postprandial hypotension in patients with autonomic failure.
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Affiliation(s)
- J S Kooner
- Department of Medicine, St Mary's Hospital Medical School, Queen Square, London, UK
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Abstract
1. To investigate the contribution of sedation to the cardiovascular effects induced by clonidine, we studied patients with essential hypertension on two separate occasions when similar levels of sedation were induced by clonidine and nitrazepam. 2. After clonidine, there was a fall in blood pressure, heart rate, digital skin vascular resistance and plasma noradrenaline which is consistent with its ability to reduce sympathetic outflow. Dissociation of the circulatory/neurohormonal and sedative responses after clonidine indicated that sedation alone is not an important factor in the blood pressure lowering effect of clonidine. 3. The absence of a fall in blood pressure, heart rate, digital skin vascular resistance and plasma noradrenaline after nitrazepam further suggest that sedation did not influence the hypotensive response in essential hypertension.
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Affiliation(s)
- J S Kooner
- Department of Medicine, St. Mary's Hospital and Medical School, London
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Kooner JS, Peart WS, Mathias CJ. The peptide release inhibitor, Octreotide (SMS 201-995), prevents the haemodynamic changes following food ingestion in normal human subjects. Q J Exp Physiol 1989; 74:569-72. [PMID: 2798766 DOI: 10.1113/expphysiol.1989.sp003308] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We have determined the haemodynamic responses to a balanced liquid meal in eight normal subjects, before and after administration of the somatostatin analogue, Octreotide (SMS 201-995), which inhibits the release of gastrointestinal peptides. In the absence of Octreotide ingestion of the meal caused a marked increase in superior mesenteric artery (SMA) blood flow. Blood pressure was maintained, presumably by a compensatory rise in cardiac output and forearm vascular resistance. After Octreotide there was a fall in SMA blood flow alone, with no further changes after food ingestion. We conclude that Octreotide prevents the haemodynamic changes following food ingestion, probably by inhibiting the release of those gastrointestinal peptides that induce splanchnic vasodilatation.
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Affiliation(s)
- J S Kooner
- Department of Medicine, St Mary's Hospital Medical School, London
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Kooner JS, Peart S, Mathias CJ. Cardiovascular and neurohormonal changes following central sympathetic blockade with clonidine in human unilateral renal artery stenosis. J Hypertens Suppl 1988; 6:S544-6. [PMID: 3071592 DOI: 10.1097/00004872-198812040-00171] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The role of central pressor mechanisms in the maintenance of blood pressure in six hypertensive patients with angiographically proven unilateral renal artery stenosis was investigated by studying the haemodynamic and hormonal responses before and after central sympathetic blockade with clonidine. To assess the dependency of blood pressure on the direct effects of angiotensin II, the same patients were studied on a separate occasion after administration of the angiotensin converting enzyme (ACE) inhibitor, captopril. There was a substantial fall in blood pressure after administration of clonidine with a smaller fall after captopril. Clonidine-induced hypotension was accompanied by a fall in cardiac output, through a reduction in the stroke volume and heart rate. Forearm vascular resistance was unchanged. There was a selective decrease in digital skin vascular resistance and plasma noradrenaline, indicating reduced sympathetic activity. Plasma renin activity and aldosterone levels did not fall. After administration of captopril, there was a fall in cardiac output due to a fall in the stroke volume but not in the heart rate. Forearm vascular resistance, digital skin vascular resistance and plasma noradrenaline were unchanged. Plasma renin activity rose and plasma aldosterone fell. We conclude that in our hypertensive patients with renal artery stenosis, clonidine lowered blood pressure by a reduction in central sympathetic activity independently of renin suppression. In these patients captopril had minimal hypotensive effects, indicating a smaller role for the direct vascular effects of angiotensin II.
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Affiliation(s)
- J S Kooner
- Medical Unit, St Mary's Hospital and Medical School, London, UK
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Kooner JS, Frankel HL, Mirando N, Peart WS, Mathias CJ. Haemodynamic, hormonal and urinary responses to postural change in tetraplegic and paraplegic man. Paraplegia 1988; 26:233-7. [PMID: 3050796 DOI: 10.1038/sc.1988.36] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We have studied the haemodynamic, hormonal and urinary effects of postural change in 6 tetraplegic patients, 6 paraplegic patients and 6 normal subjects. Measurements of blood pressure and heart rate, plasma renin activity, plasma aldosterone, urine volume and electrolyte excretion were made for 60 minutes while sitting and 60 minutes while recumbent. In tetraplegics the blood pressure was lower when sitting and rose during recumbency, unlike paraplegics and normal subjects. Plasma renin activity and aldosterone were higher in tetraplegics when sitting compared to normal subjects and did not fall during recumbency. Urine output increased significantly after recumbency in tetraplegics, but not in paraplegics or normal subjects. Both urinary sodium and potassium excretion were lower in tetraplegics and higher in paraplegics compared to normal subjects when sitting. In paraplegics the fall in both sodium and potassium excretion did not appear to be related to change in posture. Our observations indicate that recumbency induces a diuresis in tetraplegics but not in paraplegics or in normal subjects. The diuresis in tetraplegics may be related to the accompanying haemodynamic and hormonal changes induced by recumbency.
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Affiliation(s)
- J S Kooner
- Medical Unit, St Mary's Hospital Medical School, London, UK
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