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Sheldon R, Rose MS, Ritchie D, Martens K, Maxey C, Jagers J, Parboosingh J, Gerull B. Genetic Association Study in Multigenerational Kindreds With Vasovagal Syncope: Evidence for Involvement of Sex-Specific Serotonin Signaling. Circ Arrhythm Electrophysiol 2019; 12:e006884. [PMID: 30636478 DOI: 10.1161/circep.118.006884] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Several studies suggest that vasovagal syncope has a genetic origin, but this is unclear. We assessed whether plausible gene variants associate with vasovagal syncope. METHODS We studied 160 subjects in 9 kindreds comprising 82 fainters and 78 controls. The diagnosis was ascertained with the Calgary Syncope Score. Common genetic variants were genotyped for 12 genes for vascular signaling, potassium channels, the HTR1A(serotonin 5-HT1A receptor), SLC6A4(serotonin reuptake transporter), and COMT(catecholamine O-methyltransferase). Sex-specific associations between genotypes and phenotypes were tested. RESULTS In 9 out of 12 variants, there was no significant association between genotype and phenotype. However, the HTR1A(-1019) G alleles associated with syncope in males, but not in females ( P=0.005). CC and GG males had 9% versus 77% likelihoods of syncope. The SLC6A4 promoter L alleles associated with decreased syncope in males but increased in females ( P=0.059). The LL and SS males had 25% and 47% syncope likelihoods, whereas females had 75% and 50% syncope likelihoods. The COMT c.472 A alleles associated with decreased syncope in males but increased in females ( P=0.017). The GG and AA males had 50% and 15% syncope likelihoods, whereas females had 52% and 73% syncope likelihoods. CONCLUSIONS There is a sex-dependent effect of alleles of serotonin signaling and vasovagal syncope, supporting the serotonin hypothesis of the physiology of vasovagal syncope.
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Affiliation(s)
- Robert Sheldon
- Libin Cardiovascular Institute of Calgary, Alberta, Canada (R.S., M.S.R., D.R., K.M., C.M., J.J., B.G.)
| | - M Sarah Rose
- Libin Cardiovascular Institute of Calgary, Alberta, Canada (R.S., M.S.R., D.R., K.M., C.M., J.J., B.G.)
| | - Debbie Ritchie
- Libin Cardiovascular Institute of Calgary, Alberta, Canada (R.S., M.S.R., D.R., K.M., C.M., J.J., B.G.)
| | - Kristina Martens
- Libin Cardiovascular Institute of Calgary, Alberta, Canada (R.S., M.S.R., D.R., K.M., C.M., J.J., B.G.)
| | - Connor Maxey
- Libin Cardiovascular Institute of Calgary, Alberta, Canada (R.S., M.S.R., D.R., K.M., C.M., J.J., B.G.)
| | - Jennie Jagers
- Libin Cardiovascular Institute of Calgary, Alberta, Canada (R.S., M.S.R., D.R., K.M., C.M., J.J., B.G.)
| | - Jillian Parboosingh
- Alberta Children's Hospital Research Institute, University of Calgary, Canada (J.P.)
| | - Brenda Gerull
- Libin Cardiovascular Institute of Calgary, Alberta, Canada (R.S., M.S.R., D.R., K.M., C.M., J.J., B.G.).,Department Kardiovasculare Genetik, University Hospital Würzburg and University Würzburg, Germany (B.G.)
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Cho J, Zhang Y, Park SY, Joseph AM, Han C, Park HJ, Kalavalapalli S, Chun SK, Morgan D, Kim JS, Someya S, Mathews CE, Lee YJ, Wohlgemuth SE, Sunny NE, Lee HY, Choi CS, Shiratsuchi T, Oh SP, Terada N. Mitochondrial ATP transporter depletion protects mice against liver steatosis and insulin resistance. Nat Commun 2017; 8:14477. [PMID: 28205519 PMCID: PMC5316896 DOI: 10.1038/ncomms14477] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 01/04/2017] [Indexed: 12/31/2022] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is a common metabolic disorder in obese individuals. Adenine nucleotide translocase (ANT) exchanges ADP/ATP through the mitochondrial inner membrane, and Ant2 is the predominant isoform expressed in the liver. Here we demonstrate that targeted disruption of Ant2 in mouse liver enhances uncoupled respiration without damaging mitochondrial integrity and liver functions. Interestingly, liver specific Ant2 knockout mice are leaner and resistant to hepatic steatosis, obesity and insulin resistance under a lipogenic diet. Protection against fatty liver is partially recapitulated by the systemic administration of low-dose carboxyatractyloside, a specific inhibitor of ANT. Targeted manipulation of hepatic mitochondrial metabolism, particularly through inhibition of ANT, may represent an alternative approach in NAFLD and obesity treatment. Adenine nucleotide translocase (ANT) 2 promotes ADP/ATP exchange across the mitochondrial inner membrane. Cho et al. show that liver specific Ant2 deletion increases uncoupled respiration and protects mice against fatty liver and obesity-induced insulin resistance.
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Affiliation(s)
- Joonseok Cho
- Department of Pathology, University of Florida College of Medicine, Gainesville, Florida 32610, USA
| | - Yujian Zhang
- Otsuka Maryland Medicinal Laboratories, Rockville, Maryland 20850, USA
| | - Shi-Young Park
- Korea Mouse Metabolic Phenotyping Center, Lee Gil Ya Cancer and Diabetes Institute, Gachon University School of Medicine, Incheon 406-840, Korea
| | - Anna-Maria Joseph
- Department of Aging, University of Florida College of Medicine, Gainesville, Florida 32610, USA
| | - Chul Han
- Department of Aging, University of Florida College of Medicine, Gainesville, Florida 32610, USA
| | - Hyo-Jin Park
- Department of Aging, University of Florida College of Medicine, Gainesville, Florida 32610, USA
| | - Srilaxmi Kalavalapalli
- Department of Medicine, University of Florida College of Medicine, Gainesville, Florida 32610, USA
| | - Sung-Kook Chun
- Department of Surgery, University of Florida College of Medicine, Gainesville, Florida 32610, USA
| | - Drake Morgan
- Department of Psychiatry, University of Florida College of Medicine, Gainesville, Florida 32610, USA
| | - Jae-Sung Kim
- Department of Surgery, University of Florida College of Medicine, Gainesville, Florida 32610, USA
| | - Shinichi Someya
- Department of Aging, University of Florida College of Medicine, Gainesville, Florida 32610, USA
| | - Clayton E Mathews
- Department of Pathology, University of Florida College of Medicine, Gainesville, Florida 32610, USA
| | - Young Jae Lee
- Korea Mouse Metabolic Phenotyping Center, Lee Gil Ya Cancer and Diabetes Institute, Gachon University School of Medicine, Incheon 406-840, Korea
| | - Stephanie E Wohlgemuth
- Department of Animal Sciences, University of Florida College of Medicine, Gainesville, Florida 32611, USA
| | - Nishanth E Sunny
- Department of Medicine, University of Florida College of Medicine, Gainesville, Florida 32610, USA
| | - Hui-Young Lee
- Korea Mouse Metabolic Phenotyping Center, Lee Gil Ya Cancer and Diabetes Institute, Gachon University School of Medicine, Incheon 406-840, Korea
| | - Cheol Soo Choi
- Korea Mouse Metabolic Phenotyping Center, Lee Gil Ya Cancer and Diabetes Institute, Gachon University School of Medicine, Incheon 406-840, Korea.,Endocrinology, Internal Medicine, Gachon University Gil Medical Center, Incheon 405-760, Korea
| | | | - S Paul Oh
- Department of Physiology, University of Florida College of Medicine, Gainesville, Florida 32610, USA
| | - Naohiro Terada
- Department of Pathology, University of Florida College of Medicine, Gainesville, Florida 32610, USA
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Lu N, Chen J, Yuan Y, Cong X, Yang Y, Meng L, Sun K, Hui R, Zheng Y. The C-1021T polymorphism of dopamine β-hydroxylase is not associated with orthostatic hypotension in a Chinese population. J Hum Hypertens 2014; 29:173-8. [PMID: 24990418 DOI: 10.1038/jhh.2014.54] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Revised: 04/17/2014] [Accepted: 05/27/2014] [Indexed: 11/09/2022]
Abstract
To explore the association between the dopamine β-hydroxylase (DBH) gene C-1021T polymorphism and the occurrence of orthostatic hypotension (OH) in Chinese patients, the DBH C-1021T polymorphism was genotyped in 317 patients with OH and 664 age- and sex-matched controls with orthostatic normotension. All subjects underwent an upright posture study for the measurement of orthostatic blood pressure. OH was defined as a drop in blood pressure of 20/10 mm Hg or more within 3 min of assuming the upright posture. The allele frequency of the DBH C-1021T polymorphism in the orthostatic hypotensive group was similar to the orthostatic normotensive group (17.4 versus 14.9%, P>0.05). No statistical significant association was found between the distribution of the C-1021T genotypes and the risk of OH in both the orthostatic hypotensive and orthostatic normotensive groups even after adjustment for demographic parameters. Among the three different genotypes, blood pressure levels did not significantly differ in the general population in this study. The changes in orthostatic systolic or diastolic blood pressures among the different genotype groups were not detected (all P>0.05). The C-1021T polymorphism of the DBH was not associated with orthostatic hypotensive risk in a Chinese population.
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Affiliation(s)
- N Lu
- The Pediatric Cardiology, The First Hospital of Jilin University, Changchun, China
| | - J Chen
- Hypertension Division, The Sino-German Laboratory of Molecular Medicine, Cardiovascular Institute and FuWai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Y Yuan
- The Anesthesiology Department, The First Hospital of Jilin University, Changchun, China
| | - X Cong
- The Cardiovascular Center, The First Hospital of Jilin University, Changchun, China
| | - Y Yang
- The Cardiovascular Center, The First Hospital of Jilin University, Changchun, China
| | - L Meng
- The Cardiovascular Center, The First Hospital of Jilin University, Changchun, China
| | - K Sun
- Hypertension Division, The Sino-German Laboratory of Molecular Medicine, Cardiovascular Institute and FuWai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - R Hui
- Hypertension Division, The Sino-German Laboratory of Molecular Medicine, Cardiovascular Institute and FuWai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Y Zheng
- The Cardiovascular Center, The First Hospital of Jilin University, Changchun, China
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Gao Y, Lin Y, Sun K, Wang Y, Chen J, Wang H, Zhou X, Fan X, Hui R. Orthostatic Blood Pressure Dysregulation and Polymorphisms of β-Adrenergic Receptor Genes in Hypertensive Patients. J Clin Hypertens (Greenwich) 2014; 16:207-13. [PMID: 24552127 DOI: 10.1111/jch.12272] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 12/18/2013] [Accepted: 12/28/2013] [Indexed: 11/28/2022]
Affiliation(s)
- Ying Gao
- State Key Laboratory of Cardiovascular Disease; Department of Cardiology; Fuwai Hospital; National Center for Cardiovascular Diseases; Chinese Academy of Medical Sciences; Peking Union Medical College; Beijing China
| | - Yahui Lin
- State Key Laboratory of Cardiovascular Disease; Sino-German Laboratory for Molecular Medicine; Fuwai Hospital; National Center for Cardiovascular Diseases; Chinese Academy of Medical Sciences; Peking Union Medical College; Beijing China
| | - Kai Sun
- State Key Laboratory of Cardiovascular Disease; Sino-German Laboratory for Molecular Medicine; Fuwai Hospital; National Center for Cardiovascular Diseases; Chinese Academy of Medical Sciences; Peking Union Medical College; Beijing China
| | - Yibo Wang
- State Key Laboratory of Cardiovascular Disease; Sino-German Laboratory for Molecular Medicine; Fuwai Hospital; National Center for Cardiovascular Diseases; Chinese Academy of Medical Sciences; Peking Union Medical College; Beijing China
| | - Jingzhou Chen
- State Key Laboratory of Cardiovascular Disease; Sino-German Laboratory for Molecular Medicine; Fuwai Hospital; National Center for Cardiovascular Diseases; Chinese Academy of Medical Sciences; Peking Union Medical College; Beijing China
| | - Hu Wang
- State Key Laboratory of Cardiovascular Disease; Sino-German Laboratory for Molecular Medicine; Fuwai Hospital; National Center for Cardiovascular Diseases; Chinese Academy of Medical Sciences; Peking Union Medical College; Beijing China
| | - Xianliang Zhou
- State Key Laboratory of Cardiovascular Disease; Department of Cardiology; Fuwai Hospital; National Center for Cardiovascular Diseases; Chinese Academy of Medical Sciences; Peking Union Medical College; Beijing China
| | - Xiaohan Fan
- State Key Laboratory of Cardiovascular Disease; Department of Cardiology; Fuwai Hospital; National Center for Cardiovascular Diseases; Chinese Academy of Medical Sciences; Peking Union Medical College; Beijing China
| | - Rutai Hui
- State Key Laboratory of Cardiovascular Disease; Department of Cardiology; Fuwai Hospital; National Center for Cardiovascular Diseases; Chinese Academy of Medical Sciences; Peking Union Medical College; Beijing China
- State Key Laboratory of Cardiovascular Disease; Sino-German Laboratory for Molecular Medicine; Fuwai Hospital; National Center for Cardiovascular Diseases; Chinese Academy of Medical Sciences; Peking Union Medical College; Beijing China
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5
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Polymorphisms of angiotensin-converting enzyme (ACE) and ACE2 are not associated with orthostatic blood pressure dysregulation in hypertensive patients. Acta Pharmacol Sin 2009; 30:1237-44. [PMID: 19684612 DOI: 10.1038/aps.2009.110] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
AIM The genetic background of orthostatic blood pressure dysregulation remains poorly understood. Since the renin-angiotensin system plays an important role in blood pressure regulation and response to position change, we hypothesized that angiotensin-converting enzyme (ACE) and ACE2 genetic polymorphisms might contribute, at least partially, to orthostatic blood pressure dysregulation in hypertensive patients. METHODS Two tag single nucleotide polymorphisms (SNPs) of ACE2 and ACE I/D were genotyped in 3630 untreated hypertensive patients and 826 normotensive subjects. Orthostatic hypertension was defined as an increase in systolic blood pressure of 20 mmHg or more and orthostatic hypotension as a drop in blood pressure of 20/10 mmHg or more within three minutes of assumption of upright posture. RESULTS Female and male patients had similar rates of orthostatic hypertension (16.5% vs 15.3%) and hypotension (22.5% vs 23.8%). No significant differences were detected in the minor allele frequency of ACE2 rs2106809, rs2285666, or ACE I/D in either female or male patients with orthostatic hypertension (15.1%, 22.7%, 19.6%, respectively), hypotension (13.8%, 25%, 16.5%), or normal orthostatic blood pressure response (14.4%, 21.9%, 15.8%) in additive, dominant or recessive models after adjustment for confounders (all P>0.05). The orthostatic changes in systolic and diastolic blood pressure were also comparable among patients carrying different genotypes. Similar results were observed in normotensive subjects. CONCLUSION These data provide no support for the involvement of ACE or ACE2 in the genetic predisposition to orthostatic hypotension or hypertension.
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Fontenele JB, Félix FHC. Fibromyalgia and Related Medically Unexplained Symptoms: A Lost Link Between Cardiovascular and Nociception Modulation. ACTA ACUST UNITED AC 2009. [DOI: 10.1080/10582450802679904] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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7
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Sachman JL, Mayefsky JH, Ozhog S, Perlmuter LC. Birth weight predicts subclinical orthostatic hypotension in children. ACTA ACUST UNITED AC 2009. [DOI: 10.1002/huon.200800015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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8
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MITRO PETER, MUDRÁKOVÁ KLAUDIA, MIČKOVÁ HELENA, DUDÁŠ JÁN, KIRSCH PETER, VALOČIK GABRIEL. Hemodynamic Parameters and Heart Rate Variability during a Tilt Test in Relation to Gene Polymorphism of Renin-Angiotensin and Serotonin System. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2008; 31:1571-80. [DOI: 10.1111/j.1540-8159.2008.01228.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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9
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Garland EM, Black BK, Harris PA, Robertson D. Dopamine-β-hydroxylase in postural tachycardia syndrome. Am J Physiol Heart Circ Physiol 2007; 293:H684-90. [PMID: 17625104 DOI: 10.1152/ajpheart.01389.2006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Norepinephrine is frequently elevated in postural tachycardia syndrome (POTS), a syndrome of heterogeneous etiology characterized by a >30 beats/min increase in heart rate with standing. Norepinephrine is synthesized from dopamine by dopamine-β-hydroxylase (DBH). The results of a preliminary study suggested that the T allele frequency of the DBH −1021C→T polymorphism is elevated in POTS. This allele correlates with low DBH activity and might predict reduced serum DBH activity in patients with POTS. To test the hypothesis that low DBH activity and the underlying −1021C→T polymorphism are associated with increased susceptibility to POTS, we measured serum DBH activity in POTS and determined its relationship to the DBH genotype and plasma norepinephrine. Serum DBH was similar for 83 normal volunteers and 42 patients with POTS: median (range) = 22.5 (0.5–94.2) and 19.6 (0.1–68.8) nmol·min−1·ml−1, respectively ( P = 0.282). The genotype frequencies for 254 control and 157 POTS patients were not different between groups (∼63% CC genotype and ∼5% TT genotype, P = 0.319). The T allele associated with lower serum DBH in both groups [control serum DBH = 15.7 (SD 12.3) and 35.1 nmol·min−1·ml−1(SD 18.6) for T carriers and noncarriers, respectively; POTS serum DBH = 8.2 (SD 5.6) and 28.5 nmol·min−1·ml−1(SD 14.7) for T carriers and noncarriers, respectively]. High DBH in POTS was linked to elevated plasma levels of norepinephrine. Although DBH activity and genotype are unlikely to be primary determinants of susceptibility to POTS, differences in DBH activity in POTS may reflect differences in the level of sympathetic activation.
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Affiliation(s)
- Emily M Garland
- Autonomic Dysfunction Center, AA3228 Medical Center North, Vanderbilt University, Nashville, TN 37232-2195, USA.
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10
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Márquez MF, Hernández-Pacheco G, Hermosillo AG, Gómez JR, Cárdenas M, Vargas-Alarcón G. The Arg389Gly beta1-adrenergic receptor gene polymorphism and susceptibility to faint during head-up tilt test. Europace 2007; 9:585-8. [PMID: 17463065 DOI: 10.1093/europace/eum059] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AIMS To investigate the association of the Gly389 allele with positive head-up tilt test (HUT) in a Mexican Mestizo population. METHODS AND RESULTS HUT results were compared between carriers (one or two copies of the Gly389 allele) and non-carriers (Arg389Arg genotype) of the Gly389 allele of the beta(1)AR gene in 50 patients with unexplained syncope. Thirty-three patients (66%) had a positive HUT. Patients with a positive HUT had a higher Gly389 allele frequency compared with those with a negative test (30.3 vs. 3%; OR 13; pC = 0.012). Moreover, when comparing positive HUT in passive drug-free phase, positive HUT in pharmacological (nitrate) phase, and negative (both phases), a decreasing gradient in the frequencies of the Gly389 allele was found among the three groups: 45.4, 22.7, and 3%, respectively. CONCLUSION An association of positive tilt table testing to a single nucleotide polymorphism with a Gly to Arg switch at position 389 of the beta(1)AR was found. This polymorphism may contribute to susceptibility to faint during orthostatic challenge.
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Affiliation(s)
- M F Márquez
- Department of Electrocardiology, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico
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Pandian JD, Dalton K, Henderson RD, McCombe PA. Postural orthostatic tachycardia syndrome: an underrecognized disorder. Intern Med J 2007; 37:529-35. [PMID: 17445012 DOI: 10.1111/j.1445-5994.2007.01356.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Postural orthostatic tachycardia syndrome (POTS), a clinical syndrome of orthostatic intolerance characterized by excessive tachycardia and symptoms of cerebral hypoperfusion on standing, is not well recognized in Australia. The aim was to study the clinical symptomatology, results of autonomic testing and outcome in patients with POTS. METHODS Sixteen subjects from a tertiary referral centre who met the criteria for POTS were studied between January 2003 and January 2006. Ten of these patients consented to be interviewed using a validated autonomic symptom questionnaire. Heart rate responses to deep breathing and the Valsalva manoeuvre were measured using Colin BP-508 machine (WR Medical Electronic Co., Stillwater, MN, USA). Tilt studies were carried out for 10 min to 80 degrees of head-up tilting. Patient outcome was assessed as functionally normal, able to stand 30 min without symptoms, able to work and carry out recreational activities or worse on follow up. RESULTS The mean age of 10 subjects was 24.9 +/- 6.8 years, six being women. The mean duration of symptoms was 70.7 months (range 3-228 months). The common presenting orthostatic symptoms were light-headedness (100%), palpitations (90%), pallor (90%), weakness (80%) and clammy skin (80%). The mean heart rate increment during the tilt study was 51.7 +/- 14.3 b.p.m. The mean duration of follow up was 8.9 months (range 1-16 months). Only five patients were functioning normally at the follow-up visit. CONCLUSION POTS is an underrecognized but persistent autonomic disorder in young patients with a variety of symptoms and variable outcome.
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Affiliation(s)
- J D Pandian
- Department of Neurology, Royal Brisbane and Women's Hospital, Brisbane, Queensland, Australia.
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13
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Winker R, Garland EM, Rüdiger HW, Diedrich A, Biaggioni I, Ponocny I, Cascorbi I, Robertson D. Influence of an insertion variant in the 5'UTR of the endothelin-1 gene on orthostatic intolerance. Am J Med Sci 2005; 330:166-71. [PMID: 16234608 DOI: 10.1097/00000441-200510000-00003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Orthostatic intolerance is a multifactorial disease in which the genetic contribution is probably the result of a number of genes acting in combination. Recent work has shown that orthostatic intolerance is influenced by endothelial nitric oxide synthase gene polymorphisms. Since endothelin-1 (ET-1) is one of the most important vasoconstrictor peptides, a frequent adenine insertion polymorphism within the 5'-untranslated region (5'UTR), which is of functional importance for ET-1 expression, could influence orthostatic intolerance. The aim of this study was therefore to ascertain whether this frequent variant of the endothelin-1 gene influences the risk for orthostatic intolerance. METHODS We studied 257 white patients (120 cases with orthostatic intolerance and 137 controls) for genotyping of the 5'UTR I variant. From this cohort, 111 patients and 99 control subjects underwent a tilt-table test or an upright posture study, including monitoring of blood pressure, heart rate, and plasma catecholamines, in the supine position and during 30 minutes of standing. Genotyping was performed in all participants. Chi tests of independence were used to test for associations between orthostatic intolerance and genotype. In addition, an association of the insertion polymorphism with hemodynamic variables (heart rate, supine and upright blood pressure) was ascertained using one-way analysis of variance. RESULTS The 5'UTR I variant was significantly less common in patients with orthostatic intolerance (allele frequency 0.36 and 0.28, in controls and cases, respectively). Additionally, we found a significant decrease in the risk of orthostatic intolerance among people who were homozygous for the 5'UTR variant (I/I) compared with the wild-type variant (D/D) (odds ratio, 0.41; 95% confidence interval, 0.17 to 0.97; P = 0.04). No association between the 5'UTR variant and heart rate or blood pressure regardless of diagnosis was found. CONCLUSIONS Our current results suggest that the hereditary adenine insertion variant in the 5'-UTR of the endothelin-1 gene is protective for orthostatic intolerance. The increased ET-1 protein expression that has been linked with the I variant might be associated with a more efficient hemodynamic response to standing. This is likely one of several common genetic loci that may represent modifiers of orthostatic intolerance phenotypes.
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Affiliation(s)
- Robert Winker
- Division of Occupational Medicine, Medical University of Vienna, Vienna, Austria.
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Garland EM, Winker R, Williams SM, Jiang L, Stanton K, Byrne DW, Biaggioni I, Cascorbi I, Phillips JA, Harris PA, Rüdiger H, Robertson D. Endothelial NO synthase polymorphisms and postural tachycardia syndrome. Hypertension 2005; 46:1103-10. [PMID: 16203873 DOI: 10.1161/01.hyp.0000185462.08685.da] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Postural tachycardia syndrome (POTS) is a heterogeneous disorder characterized by an excessive rise in heart rate and symptoms consistent with cerebral hypoperfusion in the upright position. NO produced by endothelial NO synthase is a significant factor in the regulation of blood flow. Genetic polymorphisms in the promoter region (T-786C) and exon 7 (E298D) of the NO synthase isoform 3 gene affect enzyme activity and have been associated with a number of cardiovascular diseases. Because some findings in POTS suggest aberrant NO-mediated functions, we postulated that the variant genotypes of these polymorphisms may increase the risk of developing POTS and correlate with more severe symptoms. We genotyped 136 patients with POTS (mean age 32.2+/-9.9 years; 46 men and 90 women) from Nashville, Tenn, and Vienna, Austria, and compared them with 191 healthy volunteers (mean age 29.1+/-8.0 years; 127 men and 64 women). Participants also underwent orthostatic testing with blood pressure, heart rate, and plasma norepinephrine measurements while supine and upright. The frequencies of the -786CC and 298DD genotypes were significantly lower in patients with POTS than in control subjects (odds ratio [OR], 0.28; 95% confidence interval [CI], 0.14 to 0.57; P=0.001 for -786CC; and OR, 0.44; 95% CI, 0.21 to 0.91; P=0.033 for 298DD). According to 2-locus genotype analyses, patients with -786CC and 298EE or 298ED experienced the largest changes in heart rate and plasma norepinephrine with standing. These results indicate that NO may influence the development of POTS and the severity of POTS symptoms.
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Affiliation(s)
- Emily M Garland
- Autonomic Dysfunction Center, Vanderbilt University, Nashville, TN 37232-2195, USA.
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