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Bohmke NJ, Dixon DL, Kirkman DL. Chrono-nutrition for hypertension. Diabetes Metab Res Rev 2024; 40:e3760. [PMID: 38287721 DOI: 10.1002/dmrr.3760] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 10/27/2023] [Accepted: 11/15/2023] [Indexed: 01/31/2024]
Abstract
Despite the advancement in blood pressure (BP) lowering medications, uncontrolled hypertension persists, underscoring a stagnation of effective clinical strategies. Novel and effective lifestyle therapies are needed to prevent and manage hypertension to mitigate future progression to cardiovascular and chronic kidney diseases. Chrono-nutrition, aligning the timing of eating with environmental cues and internal biological clocks, has emerged as a potential strategy to improve BP in high-risk populations. The aim of this review is to provide an overview of the circadian physiology of BP with an emphasis on renal and vascular circadian biology. The potential of Chrono-nutrition as a lifestyle intervention for hypertension is discussed and current evidence for the efficacy of time-restricted eating is presented.
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Affiliation(s)
- Natalie J Bohmke
- Department of Kinesiology and Health Sciences, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Dave L Dixon
- Department of Pharmacotherapy and Outcomes Science, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Danielle L Kirkman
- Department of Kinesiology and Health Sciences, Virginia Commonwealth University, Richmond, Virginia, USA
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2
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Costello HM, Johnston JG, Juffre A, Crislip GR, Gumz ML. Circadian clocks of the kidney: function, mechanism, and regulation. Physiol Rev 2022; 102:1669-1701. [PMID: 35575250 PMCID: PMC9273266 DOI: 10.1152/physrev.00045.2021] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 05/03/2022] [Accepted: 05/07/2022] [Indexed: 11/22/2022] Open
Abstract
An intrinsic cellular circadian clock is located in nearly every cell of the body. The peripheral circadian clocks within the cells of the kidney contribute to the regulation of a variety of renal processes. In this review, we summarize what is currently known regarding the function, mechanism, and regulation of kidney clocks. Additionally, the effect of extrarenal physiological processes, such as endocrine and neuronal signals, on kidney function is also reviewed. Circadian rhythms in renal function are an integral part of kidney physiology, underscoring the importance of considering time of day as a key biological variable. The field of circadian renal physiology is of tremendous relevance, but with limited physiological and mechanistic information on the kidney clocks this is an area in need of extensive investigation.
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Affiliation(s)
- Hannah M Costello
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida
- Division of Nephrology, Hypertension, and Renal Transplantation, Department of Medicine, University of Florida, Gainesville, Florida
| | - Jermaine G Johnston
- Division of Nephrology, Hypertension, and Renal Transplantation, Department of Medicine, University of Florida, Gainesville, Florida
- North Florida/South Georgia Malcom Randall Department of Veterans Affairs Medical Center, Gainesville, Florida
| | - Alexandria Juffre
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida
- Division of Nephrology, Hypertension, and Renal Transplantation, Department of Medicine, University of Florida, Gainesville, Florida
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida
| | - G Ryan Crislip
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida
- Division of Nephrology, Hypertension, and Renal Transplantation, Department of Medicine, University of Florida, Gainesville, Florida
| | - Michelle L Gumz
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida
- Division of Nephrology, Hypertension, and Renal Transplantation, Department of Medicine, University of Florida, Gainesville, Florida
- North Florida/South Georgia Malcom Randall Department of Veterans Affairs Medical Center, Gainesville, Florida
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida
- Center for Integrative Cardiovascular and Metabolic Diseases, University of Florida, Gainesville, Florida
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3
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Adam RJ, Williams AC, Kriegel AJ. Comparison of the Surgical Resection and Infarct 5/6 Nephrectomy Rat Models of Chronic Kidney Disease. Am J Physiol Renal Physiol 2022; 322:F639-F654. [PMID: 35379002 DOI: 10.1152/ajprenal.00398.2021] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The 5/6 nephrectomy rat remnant kidney model is commonly employed to study chronic kidney disease (CKD). This model requires removal of one whole kidney and two-thirds of the other. The two most common ways of producing the remnant kidney are surgical resection of poles, known as the polectomy (Pol) model, or ligation of upper and lower renal arterial branches, resulting in pole infarction (Inf). These models have much in common, but also major phenotypic differences, and thus respectively model unique aspects of human CKD. The purpose of this review is to summarize phenotypic similarities and differences between these two models and their relation to human CKD, while emphasizing their vascular phenotype. In this article we review studies that have evaluated arterial blood pressure, the renin-angiotensin-aldosterone-system (RAAS), autoregulation, nitric oxide, single nephron physiology, angiogenic and anti-angiogenic factors, and capillary rarefaction in these two models. Phenotypic similarities: both models spontaneously develop hallmarks of human CKD including uremia, fibrosis, capillary rarefaction, and progressive renal function decline. They both undergo whole-organ hypertrophy, hyperfiltration of functional nephrons, reduced renal expression of angiogenic factor VEGF, increased renal expression of the anti-angiogenic thrombospondin-1, impaired renal autoregulation, and abnormal vascular nitric oxide physiology. Key phenotypic differences: the Inf model develops rapid-onset, moderate-to-severe systemic hypertension, and the Pol model early normotension followed by mild-to-moderate hypertension. The Inf rat has a markedly more active renin-angiotensin-aldosterone-system. Comparison of these two models facilitates understanding of how they can be utilized for studying CKD pathophysiology (e.g., RAAS dependent or independent pathology).
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Affiliation(s)
- Ryan J Adam
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Adaysha C Williams
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Alison J Kriegel
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, United States.,Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States.,Center of Systems Molecular Medicine, Medical College of Wisconsin, Milwaukee, WI, United States
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Cha RH, Lee H, Lee JP, Song YR, Kim SG, Kim YS. Physician perceptions of blood pressure control in patients with chronic kidney disease and target blood pressure achievement rate. Kidney Res Clin Pract 2017; 36:349-357. [PMID: 29285427 PMCID: PMC5743044 DOI: 10.23876/j.krcp.2017.36.4.349] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 09/25/2017] [Accepted: 09/26/2017] [Indexed: 01/11/2023] Open
Abstract
Background Blood pressure (BP) control is the most-established method for the prevention of chronic kidney disease (CKD) progression. However, the ideal BP target for CKD patients is still under debate. Methods We performed a survey of regular registered members of the Korean Society of Nephrology to determine physician perceptions of BP control in patients with CKD. In addition, we evaluated the target BP achievement rate using data from the APrODiTe-2 study. Results Two-thirds of physicians considered the target BP for CKD to be < 130/85 mmHg. The systolic BP (SBP) thresholds for diabetic CKD, proteinuria ≥ 300 mg/day, 30 ≤ glomerular filtration rate (GFR) < 60 mL/min/1.73 m2, age < 60 years, and the presence of atherosclerotic (ASO) complications were significantly lower than the SBP thresholds of the opposite parameters. The three major hurdles to controlling BP were non-compliance with lifestyle modification and medications, and self-report of well-controlled home BP. Most physicians prescribed home and ambulatory BP monitoring to less than 50% of their patients. The target BP achievement rates using the SBP thresholds in this survey were as follows: non-diabetic (69.3%); diabetic (29.5%); proteinuria < 300 mg/day (72.3%); proteinuria > 300 mg/day (33.7%); GFR ≥ 60 (76.4%); GFR < 30 (47.8%); no evidence of ASO (67.8%); and the presence of ASO (42.9%). Conclusion The target BP was lower in patients with higher cerebro-cardiovascular risks. These patient groups also showed lower target BP achievement rates. We also found a relatively lower application and clinical reflection rate of home or ambulatory BP monitoring.
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Affiliation(s)
- Ran-Hui Cha
- Department of Internal Medicine, National Medical Center, Seoul, Korea
| | - Hajeong Lee
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Jung Pyo Lee
- Department of Internal Medicine, SMG-SNU Boramae Medical Center, Seoul, Korea
| | - Young Rim Song
- Department of Internal Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea
| | - Sung Gyun Kim
- Department of Internal Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea
| | - Yon Su Kim
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.,Kidney Research Institute, Seoul National University Medical Research Center, Seoul, Korea
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5
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Changes of blood pressure patterns and target organ damage in patients with chronic kidney disease. J Hypertens 2017; 35:593-601. [DOI: 10.1097/hjh.0000000000001185] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Abstract
Since the kidney is integral to maintenance of fluid and ion homeostasis, and therefore blood pressure regulation, its proper function is paramount. Circadian fluctuations in blood pressure, renal blood flow, glomerular filtration rate, and sodium and water excretion have been documented for decades, if not longer. Recent studies on the role of circadian clock proteins in the regulation of a variety of renal transport genes suggest that the molecular clock in the kidney controls circadian fluctuations in renal function. The circadian clock appears to be a critical regulator of renal function with important implications for the treatment of renal pathologies, which include chronic kidney disease and hypertension. The development, regulation, and mechanism of the kidney clock are reviewed here.
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Affiliation(s)
- Kristen Solocinski
- Department of Medicine, Division of Nephrology, Hypertension, and Renal Transplantation, University of Florida, Gainesville, FloridaDepartment of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida
| | - Michelle L Gumz
- Department of Medicine, Division of Nephrology, Hypertension, and Renal Transplantation, University of Florida, Gainesville, FloridaDepartment of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida
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Ritvo P, Stefanyk LE, Azargive S, Stojanovic S, Stollon F, Habot J, Khaykin Y, Fair T, Pirbaglou M. Functional capacity and heart rate response: associations with nocturnal hypertension. BMC Cardiovasc Disord 2015. [PMID: 26197812 PMCID: PMC4511245 DOI: 10.1186/s12872-015-0064-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Background Absences of normative, 10–20 % declines in blood pressure (BP) at night, termed nocturnal non-dipping, are linked to increased cardiovascular mortality risks. Current literature has linked these absences to psychological states, hormonal imbalance, and disorders involving hyper-arousal. This study focuses on evaluating associations between nocturnal non-dipping and indices of functional cardiac capacity and fitness. Methods The current study was a cross-sectional evaluation of the associations between physical capacity variables e.g. Metabolic Equivalent (MET) and Maximum Heart Rate (MHR), Heart rate reserve (HRR), and degree of reduction in nocturnal systolic blood pressure (SBP) or diastolic blood pressure (DBP), also known as ‘dipping’. The study sample included 96 cardiac patient participants assessed for physical capacity and ambulatory blood pressure monitoring. In addition to evaluating differences between groups on nocturnal BP ‘dipping’, physical capacity, diagnoses, and medications, linear regression analyses were used to evaluate potential associations between nocturnal SBP and DBP ‘dipping’, and physical capacity indices. Results 45 males and 14 females or 61.5 % of 96 consented participants met criteria as non-dippers (<10 % drop in nocturnal BP). Although non-dippers were older (p = .01) and had a lower maximum heart rate during the Bruce stress test (p = .05), dipping was only significantly associated with Type 2 Diabetes co-morbidity and was not associated with type of medication. Within separate linear regression models controlling for participant sex, MHR (β = 0.26, p = .01, R2 = .06), HRR (β = 0. 19, p = .05, R2 = .05), and METs (β = 0.21, p = .04, R2 = .04) emerged as significant but small predictors of degree of nighttime SBP dipping. Similar relationships were not observed for DBP. Conclusions Since the variables reflecting basic heart function and fitness (MHR and METs), did not account for appreciable variances in nighttime BP, nocturnal hypertension appears to be a complex, multi-faceted phenomena.
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Affiliation(s)
- Paul Ritvo
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada. .,Department of Psychology, York University, Toronto, ON, Canada. .,Research, Prevention and Cancer Control, Cancer Care Ontario, Toronto, ON, Canada. .,Department of Psychiatry, University of Toronto, Toronto, ON, Canada. .,Department of Community and Family Medicine, University of Toronto, Toronto, ON, Canada.
| | - Leslie E Stefanyk
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada.
| | - Saam Azargive
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada.
| | - Slobodan Stojanovic
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada.
| | - Faye Stollon
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada.
| | - Juda Habot
- Division of Cardiology, Southlake Regional Health Centre, Newmarket, ON, Canada.
| | - Yaariv Khaykin
- Division of Cardiology, Southlake Regional Health Centre, Newmarket, ON, Canada. .,Faculty of Medicine, University of Toronto, Toronto, ON, Canada.
| | - Terry Fair
- Division of Cardiology, Southlake Regional Health Centre, Newmarket, ON, Canada.
| | - Meysam Pirbaglou
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada.
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Litovkina O, Nekipelova E, Dvornyk V, Polonikov A, Efremova O, Zhernakova N, Reshetnikov E, Churnosov M. Genes involved in the regulation of vascular homeostasis determine renal survival rate in patients with chronic glomerulonephritis. Gene 2014; 546:112-6. [PMID: 24727057 DOI: 10.1016/j.gene.2014.04.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2013] [Revised: 04/06/2014] [Accepted: 04/09/2014] [Indexed: 10/25/2022]
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Association between blood pressure and target organ damage in patients with chronic kidney disease and hypertension: results of the APrODiTe study. Hypertens Res 2013; 37:172-8. [PMID: 24048482 DOI: 10.1038/hr.2013.127] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2013] [Revised: 07/24/2013] [Accepted: 07/25/2013] [Indexed: 11/08/2022]
Abstract
Blood pressure control is the most established practice for preventing the progression of chronic kidney disease. Evidence addressing blood pressure control status or nocturnal blood pressure dipping in Korean hypertensive patients with chronic kidney disease is scarce. We recruited 1317 hypertensive patients (chronic kidney disease stages 2-4, median age 58) from 21 centers in Korea. These patients underwent office and ambulatory blood pressure monitoring. High office and ambulatory blood pressure were defined as >140/90 mm Hg and >135/85 mm Hg (daytime)/ >120/70 mm Hg (nighttime), respectively. The blood pressure control status was as follows: true controlled (19%), white-coat (4.3%), masked (33.9%) and sustained uncontrolled (42.3%) hypertension. The dipping status was as follows: extreme-dipping (14.9%), dipping (33.3%), non-dipping (34.5%) and reverse-dipping (17.3%). Masked and sustained hypertension as well as non-dipping/reverse-dipping was more apparent in proportion to renal dysfunction and the extent of proteinuria. Ageing (58 years), male gender, obesity, diabetic nephropathy and proteinuria (>300 mg g(-1) Cr or dipstick proteinuria1+) were independently associated with sustained uncontrolled hypertension. Diabetic nephropathy, old age, a history of stable angina/heart failure, advanced renal dysfunction and higher proteinuria levels were also significantly associated with non-dipping and reverse-dipping. Half of Korean chronic kidney disease patients had uncontrolled blood pressure and a non-dipping nocturnal blood pressure pattern. Future studies are warranted to assess the predictive values of ambulatory blood pressure for cardiorenal events in Korean chronic kidney disease patients.
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Doménech M, Berruezo A, Molina I, Mont L, Coca A. La presión arterial ambulatoria nocturna se asocia al remodelado auricular y la activación neurohormonal en pacientes con fibrilación auricular idiopática. Rev Esp Cardiol 2013. [DOI: 10.1016/j.recesp.2012.11.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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11
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Nighttime ambulatory blood pressure is associated with atrial remodelling and neurohormonal activation in patients with idiopathic atrial fibrillation. ACTA ACUST UNITED AC 2013; 66:458-63. [PMID: 24776048 DOI: 10.1016/j.rec.2012.11.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 11/28/2012] [Indexed: 11/20/2022]
Abstract
INTRODUCTION AND OBJECTIVES Hypertension is a risk factor for atrial fibrillation. Activation of the renin-angiotensin-system seems to be involved in atrial enlargement, with release of atrial and brain natriuretic peptides. The aim of this study was to evaluate the relationship between ambulatory blood pressure and levels of natriuretic peptides, with left atrial size in normotensives with idiopathic atrial fibrillation. METHODS This was a cross-sectional study in patients with idiopathic atrial fibrillation. The following measurements were recorded during the course of the study: office and 24-h ambulatory blood pressure, atrial and brain natriuretic peptides, plasma renin, aldosterone, and angiotensin-converting enzyme. RESULTS Forty-eight patients (mean age 55 [10] years; 70.6% male) were included in the study. Mean office sitting blood pressure values were 132.49 (14.9)/80.96 (9.2) mmHg. Mean 24-h ambulatory systolic and diastolic blood pressure values were 121.10 (8.3)/72.11 (6.8) mmHg (daytime, 126.8 [9.7]/77.58 [7.9] mmHg; nighttime, 114.56 [11.6]/68.6 [8.8] mmHg). A clear trend towards increased left atrial size with higher ambulatory blood pressure values was noted, which was statistically significant for nighttime values (r=0.34; P=.020 for systolic and r=0.51; p=.0001 for diastolic). A significant correlation between atrial natriuretic peptide and nighttime systolic (r=0.297; P=.047) and diastolic (r=0.312; P=.037) blood pressure was observed. Significant correlations were also observed between left atrial size and atrial natriuretic peptide levels (r=0.577; p<.0001) and brain natriuretic peptide levels (r=0.379; P=.012). CONCLUSIONS Nighttime blood pressure is associated with left atrial size and the release of natriuretic peptides in normotensive patients with idiopathic atrial fibrillation.
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Nocturnal medications dosing: does it really make a difference in blood pressure control among patients with chronic kidney disease? Curr Hypertens Rep 2013; 14:449-54. [PMID: 22836387 DOI: 10.1007/s11906-012-0295-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Ambulatory blood pressure (BP) monitoring is superior to clinic BP monitoring in predicting long-term consequences of hypertension. This has raised interest in diurnal variation in BP and elevation in nighttime BP as a prognostic and therapeutic target. Several studies have identified prevalence of nocturnal hypertension in patients with accelerated progression of chronic kidney disease and target organ damage. Some studies suggest that nocturnal BP can be lowered by changing administration of antihypertensive medication to bed time; whether that results in retarding kidney disease progression is not very clear. Further research is needed to determine if certain classes of medications or interventions are superior in controlling nocturnal hypertension, and protocols need to be developed to screen patients for monitoring nocturnal BP. Further studies are needed to evaluate long-term renal outcomes of evening dosing in patients with nocturnal hypertension and chronic kidney disease.
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Feldstein C, Akopian M, Olivieri AO, Garrido D. Association Between Nondipper Behavior and Serum Calcium in Hypertensive Patients with Mild-to-Moderate Chronic Renal Dysfunction. Clin Exp Hypertens 2012; 34:417-23. [DOI: 10.3109/10641963.2012.665541] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Giles TD, Alessi T, Purkayastha D, Zappe D. Comparative Efficacy of Aliskiren/Valsartan vs Valsartan in Nocturnal Dipper and Nondipper Hypertensive Patients: A Pooled Analysis. J Clin Hypertens (Greenwich) 2012; 14:299-306. [DOI: 10.1111/j.1751-7176.2012.00608.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Time rate of blood pressure variation is associated with impaired renal function in hypertensive patients. J Hypertens 2010; 27:2244-8. [PMID: 19644388 DOI: 10.1097/hjh.0b013e328330a94f] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
OBJECTIVES The rate of blood pressure (BP) variation has been positively associated with intima-media thickness of common carotid arteries and left ventricular mass. We evaluated the association between the rate of BP variation derived from ambulatory blood pressure monitoring (ABPM) data analysis and impaired renal function. METHODS Twenty-four-hour ABPM was performed in 803 untreated hypertensive patients. The estimated glomerular filtration rate (eGFR) was assessed using the abbreviated equation of the Modification Diet for Renal Disease study. Patients were divided into two groups: those with an eGFR less than 60 ml/min per 1.73 m(2) (group A) and those with an eGFR 60 ml/min per 1.73 m(2) or more (group B). RESULTS The 24-h rate of systolic BP variation was significantly (P = 0.004) higher in group A [0.616 mmHg/min; 95% confidence interval (CI) 0.596-0.636] than in group B patients (0.585 mmHg/min; 95% CI 0.578-0.591), even after adjusting for baseline characteristics and ABPM parameters. In the entire study population, the multiple logistic regression models revealed the following variables as independent determinants of impaired renal function: age, male sex, office systolic BP and 24-h rate of systolic BP variation. In this model, the odds ratio for impaired renal function associated with each 0.1 mmHg/min increase in 24-h rate of systolic BP variation was 1.49 (95% CI 1.18-1.88, P = 0.001). CONCLUSION The 24-h rate of SBP variation is independently associated with impaired renal function. Target-organ damage in hypertensive patients, in addition to BP levels, dipping status and BP variability, may also be related to a steeper rate of BP fluctuations.
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Portaluppi F, Cortelli P, Buonaura GC, Smolensky MH, Fabbian F. Do restless legs syndrome (RLS) and periodic limb movements of sleep (PLMS) play a role in nocturnal hypertension and increased cardiovascular risk of renally impaired patients? Chronobiol Int 2009; 26:1206-21. [PMID: 19731113 DOI: 10.3109/07420520903245276] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Hypertension can cause or promote renal failure and is related to cardiovascular mortality, the major cause of death in patients with renal impairment. Changes in the circadian BP pattern, particularly the blunting or reversal of the nocturnal decline in BP, are common in chronic renal failure. These changes in turn are among the major determinants of left ventricular hypertrophy. Using a chronobiological approach, it is possible to obtain better insight into the reciprocal relationship between hypertension, renal disease, and increased cardiovascular risk of renal patients. Disruption of the normal circadian rhythm of rest/activity may be hypothesized to underlie the high cardiovascular morbidity and mortality of such patients. Epidemiological studies reveal that hemodialysis patients experience poor subjective sleep quality and insomnia and, in comparison to healthy persons, are more likely to show shorter sleep duration and lower sleep efficiency. Sleep apnea may be present and is usually investigated in these patients; however, the prevalence of restless legs syndrome (RLS), which is high in dialysis patients and which has been associated with increased risk for cardiovascular disease in the general population, could also play a role in the pathogenesis of sleep-time hypertension in renal patients. Careful assessment of sleep quality, in particular, diagnostic screening for RLS and periodic limb movements (PLM) in renal patients, is highly recommended. In renal failure, attention to sleep quality and related perturbations of the sleep/wake cycle may help prevent the occurrence and progression of cardiovascular disease.
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Affiliation(s)
- Francesco Portaluppi
- Hypertension Center and Clinica Medica, University Hospital S. Anna of Ferrara, Ferrara, Italy.
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Abstract
PURPOSE OF REVIEW Several studies have identified the presence of altered diurnal blood pressure patterns, specifically elevated nighttime blood pressure in patients with chronic kidney disease. The lack of nocturnal decline in blood pressure is associated with markers of hypertensive target organ damage and predictive of long-term clinical outcomes. The purpose of this review is to summarize the literature in this area and explore the potential for use of nighttime blood pressure for improving risk stratification and as a therapeutic target. RECENT FINDINGS The mechanisms of persistent elevation of blood pressure at night in chronic kidney disease are likely to be multifactorial, including altered sodium handling and sympathetic activation among others. Elevated nocturnal blood pressures have been shown to be associated with increased adverse clinical outcomes. Recent studies demonstrate that it is feasible to lower nocturnal blood pressure by modifying the time of administration of antihypertensive medications. SUMMARY Currently, clinical blood pressure measurements are assessed and targeted for drug therapy. This article shows the importance of measuring ambulatory blood pressures, specifically nocturnal blood pressures to improve risk stratification. More research needs to be done to identify interventions that lower nighttime blood pressure, and test their efficacy in improving clinical outcomes.
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Jørgensen ME, Pedersen MB, Siggaard C, Sørensen TB, Mulvad G, Hansen JC, Skjoldborg H, Pedersen EB. Ethnic, geographic and dietary influences upon vasoactive hormones and blood pressure among Greenland Inuit and Danes. Blood Press 2009; 12:298-306. [PMID: 14763661 DOI: 10.1080/08037050310016646] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
AIM To study levels of vasoactive hormones and urinary excretion of sodium and potassium between groups of Greenland Inuit and Danes, and to analyse the relationship between these hormones and 24-h blood pressure, including nightly blood pressure dips and pulse pressure. METHODS 145 Greenlandic participants were categorized in three groups according to degree of westernization, based on dietary habits and current place of residence; 41 Danes were included as controls. Twenty-four-hour blood pressure was measured. Venous plasma concentrations of vasoactive hormones were measured. Urine was collected for 24 hours for analysis of excretion of sodium and potassium. RESULTS The Inuit population of Greenland had a lower diastolic blood pressure, a higher pulse pressure and lower nocturnal blood pressure dip than Danes had. Angiotensin II in plasma and urine excretion of potassium were higher among Greenlanders compared with Danes, irrespective of diet and place of residence. Aldosterone and urine excretion of sodium were significantly higher among participants in Denmark compared with participants in Greenland. Brain natriuretic peptide and atrial natriuretic peptide were independently and negatively associated with diastolic blood pressure, and vasopressin was positively associated with systolic blood pressure and pulse pressure. Ethnic differences in the effect of vasoactive hormones or urinary sodium and potassium excretion could not explain the difference in blood pressure. CONCLUSION It is suggested that a high dietary intake of potassium and low sodium intake among Greenlanders may affect blood pressure. Further attention should be drawn to the occurrence of high pulse pressure and high activity in the renin-angiotensin system in Inuit populations.
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Pogue V, Rahman M, Lipkowitz M, Toto R, Miller E, Faulkner M, Rostand S, Hiremath L, Sika M, Kendrick C, Hu B, Greene T, Appel L, Phillips RA. Disparate estimates of hypertension control from ambulatory and clinic blood pressure measurements in hypertensive kidney disease. Hypertension 2009; 53:20-7. [PMID: 19047584 DOI: 10.1161/hypertensionaha.108.115154] [Citation(s) in RCA: 222] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Ambulatory blood pressure (ABP) monitoring provides unique information about day-night patterns of blood pressure (BP). The objectives of this article were to describe ABP patterns in African Americans with hypertensive kidney disease, to examine the joint distribution of clinic BP and ABP, and to determine associations of hypertensive target organ damage with clinic BP and ABP. This study is a cross-sectional analysis of baseline data from the African American Study of Kidney Disease Cohort Study. Masked hypertension was defined by elevated daytime (>or= 135/85 mm Hg) or elevated nighttime (>or= 120/70 mm Hg) ABP in those with controlled clinic BP (<140/90 mm Hg); nondipping was defined by a
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Affiliation(s)
- Velvie Pogue
- Division of Nephrology, Department of Medicine, Columbia University Medical Center, Harlem Hospital Center, New York, NY 10037, USA.
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20
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Elung-Jensen T, Strandgaard S, Kamper AL. Longitudinal observations on circadian blood pressure variation in chronic kidney disease stages 3-5. Nephrol Dial Transplant 2008; 23:2873-8. [PMID: 18353888 DOI: 10.1093/ndt/gfn126] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND It has been suggested that status as a 'non-dipper' determined from 24-h blood pressure (BP) recordings is associated with increased risk of end-organ damage but little is known about the consistency of dipper status in renal patients. The present post hoc analysis evaluated dipper/non-dipper status prospectively in a study on dosage of enalapril in progressive chronic kidney disease (CKD) stages 3-5. METHODS In 34 patients, 24-h ambulatory BP (A&D TM2421) was measured at baseline and every 4 months for 1 year or until the need for renal replacement therapy. For each BP recording patients were classified as dippers or non-dippers based on the presence or absence of a nighttime reduction in both systolic and diastolic BP > 10%. Antihypertensive treatment aimed at an office BP < 120/80 mmHg. GFR was measured by the plasma clearance of (51)Cr-EDTA and albuminuria was determined from 24-h collections. RESULTS A total of 125 24-h BP recordings were made. Ten patients were constant dippers and five were constant non-dippers throughout the study whereas nineteen patients changed dipping status apparently at random. When analysing pairs of sequential recordings in the individual patient, non-dipper and dipper status remained unaltered in 25 (27%) and 32 (35%) of comparisons, respectively, whereas it was inconsistent in 34 (38%) of cases. No correlation between dipper status and GFR, decline in renal function, degree of albuminuria or BP level could be demonstrated. CONCLUSIONS The consistency of circadian BP variation seems to be poor in CKD stages 3-5 and single measurements of 24-h ambulatory BP are therefore probably inadequate for the evaluation of dipping status.
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Affiliation(s)
- Thomas Elung-Jensen
- Department of Nephrology Rigshospitalet, Blegdamsvej 9, 2200 København N, Denmark.
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21
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Rahman M, Appel LJ. Should Reducing Nocturnal Blood Pressure Be a Therapeutic Target in CKD? The Time Is Ripe for a Clinical Outcomes Trial. Am J Kidney Dis 2007; 50:901-3. [DOI: 10.1053/j.ajkd.2007.10.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2007] [Accepted: 10/16/2007] [Indexed: 11/11/2022]
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Seeman T, Palyzová D, Dusek J, Janda J. Reduced nocturnal blood pressure dip and sustained nighttime hypertension are specific markers of secondary hypertension. J Pediatr 2005; 147:366-71. [PMID: 16182677 DOI: 10.1016/j.jpeds.2005.04.042] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2004] [Revised: 02/21/2005] [Accepted: 04/15/2005] [Indexed: 12/23/2022]
Abstract
OBJECTIVE To investigate with the use of ambulatory blood pressure (BP) monitoring whether nocturnal BP dip and nighttime BP values are different in children with untreated primary and secondary hypertension. STUDY DESIGN Ambulatory BP monitoring studies from 145 children with untreated hypertension were retrospectively analyzed. Forty-five children had primary hypertension and 100 children had secondary hypertension. RESULTS Children with secondary hypertension had lower nocturnal BP dip for systolic and diastolic BP in comparison to children with primary hypertension (8% +/- 5% vs 14% +/- 4% for systolic and 14% +/- 7% vs 22% +/- 5% for diastolic BP, P < .0001 for both). Eleven percent of children with primary hypertension were classified as nondipper (BP dip <10%) for systolic BP and no child for diastolic BP; on the contrary, in children with secondary hypertension, 65% were nondippers for systolic and 21% for diastolic BP. Nocturnal systolic and diastolic BP loads were significantly greater in children with secondary hypertension than in those with primary hypertension. CONCLUSIONS Reduced nocturnal BP dip and sustained nighttime BP elevation are specific markers of secondary hypertension in children with untreated hypertension. Children with blunted nocturnal BP dip or sustained nighttime hypertension should be thoroughly investigated searching for the underlying cause of hypertension.
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Affiliation(s)
- Tomás Seeman
- Department of Pediatrics, University Hospital Motol, 2nd School of Medicine, Charles University Prague, Prague, Czech Republic
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23
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Mentari E, Rahman M. Blood pressure and progression of chronic kidney disease: Importance of systolic, diastolic, or diurnal variation. Curr Hypertens Rep 2004; 6:400-4. [PMID: 15341694 DOI: 10.1007/s11906-004-0060-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Several studies show that systolic blood pressure is an important predictor of renal disease progression, just as it is linked with cardiovascular consequences in hypertension. In contrast, particularly in older patients, diastolic blood pressure was not independently associated with risk of kidney disease progression in the same studies. Pulse pressure has been shown to be equivalent in predicting renal outcomes, but might not have added value after adjusting for systolic blood pressure. Several cross- sectional studies present a strong correlation of ambulatory blood pressure monitoring values with microalbuminuria, compared with office-based blood pressure measurements. Small, prospective studies have shown an association between loss of nocturnal blood pressure decline and outcomes, including microalbuminuria, accelerated kidney disease progression, and mortality.
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Affiliation(s)
- Evelyn Mentari
- Division of Nephrology and Hypertension, Case Western Reserve University, University Hospitals of Cleveland / Cleveland VA Medical Center, 11100 Euclid Avenue, Cleveland, OH 44106, USA
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Kööbi P, Kalliovalkama J, Jolma P, Rysä J, Ruskoaho H, Vuolteenaho O, Kähönen M, Tikkanen I, Fan M, Ylitalo P, Pörsti I. AT1 receptor blockade improves vasorelaxation in experimental renal failure. Hypertension 2003; 41:1364-71. [PMID: 12743014 DOI: 10.1161/01.hyp.0000073782.30879.16] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
It is not known whether angiotensin II type 1 receptor antagonists can influence the function and morphology of small arteries in renal failure. We investigated the effect of 8-week losartan therapy (20 mg/kg per day) on isolated mesenteric resistance arteries by wire and pressure myographs in 5/6 nephrectomized rats. Plasma urea nitrogen was elevated 1.6-fold after nephrectomy, and ventricular synthesis of atrial and B-type natriuretic peptides was increased 2.2-fold and 1.7-fold, respectively, whereas blood pressure was not affected. Losartan did not influence these variables. The endothelium-mediated relaxation to acetylcholine was impaired in nephrectomized rats in the absence and presence of nitric oxide synthase and cyclooxygenase inhibition. Blockade of calcium-activated potassium channels by charybdotoxin and apamin reduced the remaining acetylcholine response, and this effect was less marked in nephrectomized than in sham-operated rats. Relaxation to levcromakalim, a vasodilator acting through adenosine triphosphate-sensitive potassium channels, was also impaired after nephrectomy. The arteries of nephrectomized rats showed eutrophic inward remodeling: Wall-to-lumen ratio was increased without change in wall cross-sectional area. All changes in arterial relaxation and morphology were normalized by losartan therapy. Aortic ACE content, measured by autoradiography, directly correlated to the plasma level of urea nitrogen, suggesting that renal failure has an enhancing influence on the vascular renin-angiotensin system. Losartan normalized relaxation and morphology of resistance arteries in experimental renal failure, independent of its influence on blood pressure, impaired kidney function, or volume overload. The mechanism of improved vasodilation by losartan may include enhanced relaxation through potassium channels.
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Affiliation(s)
- Peeter Kööbi
- Department of Pharmacological Sciences, University of Tampere, Finland
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Abstract
Outcome studies in diabetic nephropathy have focused on strategies to prevent progression of diabetic nephropathy, the leading cause of ESRD in the United States. Once diabetics develop overt nephropathy, prognosis is poor. Risk factors for diabetic nephropathy are discussed, and include hyperglycemia, hypertension, angiotensin II, proteinuria, dyslipidemia, smoking, and anemia. Major outcomes as well as outcome studies in diabetic nephropathy for patients with microalbuminuria and macroalbuminuria are reviewed. Furthermore, the role of therapy with angiotensin converting enzyme inhibitors, angiotensin II receptor blockers, calcium channel blockers, and mineralocorticoid receptor antagonists as well as selected combination therapy are discussed. Recommendations for therapy with ace inhibitors and angiotensin II receptor blockers are made based on this evidence.
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Affiliation(s)
- Anupama Mohanram
- University of Texas Southwestern Medical Center Dallas, Dallas, TX 75390-8856, USA
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Abbott KC, Bakris GL. Treatment of the diabetic patient: focus on cardiovascular and renal risk reduction. PROGRESS IN BRAIN RESEARCH 2002; 139:289-98. [PMID: 12436944 DOI: 10.1016/s0079-6123(02)39025-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Diabetes mellitus increases the risk for hypertension and associated cardiovascular diseases, including coronary, cerebrovascular, renal and peripheral vascular disease. The risk for developing cardiovascular disease is increased when both diabetes and hypertension co-exist; in fact, over 11 million Americans have both diabetes and hypertension. These numbers will continue to climb, internationally, since the leading associated risk for diabetes development, obesity, has reached epidemic proportions, globally. Moreover, the frequent association of diabetes with dyslipidemia, as well as coagulation, endothelial, and metabolic abnormalities also aggravates the underlying vascular disease process in patients who possess these comorbid conditions. The renin-angiotensin-aldosterone system (RAS) and arginine vasopressin (AVP) are overactivated in both hypertension and diabetes. Drugs that inhibit this system, such as ACE inhibitors and more recently angiotensin receptor antagonists (ARBs), have proven beneficial effects on the micro- and macrovascular complications of diabetes, especially the kidney. The BRILLIANT study showed that lisinopril reduces microalbuminuria better than CCB therapy. Numerous other long-term studies confirm this association with ACE inhibitors including the HOPE trial. Furthermore, the European Controlled trial of Lisinopril in Insulin-dependent Diabetes (EUCLID) study, showed that lisinopril slowed the progression of renal disease, even in individuals with mild albuminuria. In fact, there are now five appropriately powered randomized placebo-controlled trials to show that both ACE inhibitors and ARBs slow progression of diabetic nephropathy in people with type 2 diabetes. These effects were shown to be better than conventional blood pressure lowering therapy, including dihydropyridine CCBs. In patients with microalbuminuria, ACE inhibitors and ARBs reduce the progression of microalbuminuria to proteinuria and provide a risk reduction of between 38 and 60% for progression to proteinuria. This is important since microalbuminuria is known to be associated with increased vascular permeability and decreased responsiveness to vasodilatory stimuli. Recently, increased AVP levels have been lined to microalbuminuria and hyperfiltration in diabetes. The microvascular and macrovascular benefits of ACE inhibition, ARBs and possible role of AVP antagonists in diabetic patients will be discussed, as will be recommendations for its clinical use.
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Affiliation(s)
- Kevin C Abbott
- Nephrology Service, Walter Reed Army Medical Center, Washington, DC, USA
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Mora-Maciá J, Cases A, Alami M, Agraz I, Barceló P, Esqué J. [Analysis of heart rate as a risk factor associated with the progression of chronic renal failure]. Med Clin (Barc) 2002; 119:245-8. [PMID: 12236983 DOI: 10.1016/s0025-7753(02)73376-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND An increased heart rate is associated with an increased risk of cardiovascular and non-cardiovascular death. However, the possible relationship between heart rate and the rate of progression of renal disease has not been assessed so far. PATIENTS AND METHOD Twenty-four-hour ambulatory blood pressure and heart rate recordings at baseline conditions were obtained in 24 patients with non-diabetic chronic renal failure and hypertension. The rate of progression of renal disease was estimated on the basis of the slope of the reciprocal of serum creatinine concentration against time. RESULTS After a mean follow-up of 38 months, the rate of progression of renal failure was 0.004 (0.039) dL/mg/month. Progression of renal disease showed no correlation with baseline ambulatory systolic or diastolic blood pressures, and did not differ between dipper and non-dipper patients. Twenty-four-hour (r = 0.40, p = 0.05) and day-time (r = 0.534, p = 0.007) heart rates showed a relationship with the progression of renal failure. Proteinuria displayed a correlation with night-time heart rate (r = 0.405, p = 0.05) but not with the progression of renal failure. CONCLUSIONS Baseline ambulatory heart rate, especially day-time heart rate, is associated with the decline of renal function in non-diabetic patients with chronic renal failure, suggesting that heart rate is a risk factor (or marker) for renal disease progression. Prospective controlled studies with a larger sample of patients are needed to confirm these findings and to investigate the possible mechanisms involved in this association.
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Affiliation(s)
- José Mora-Maciá
- Unidad de Nefrologia, Fundacio Sanitaria d'Igualada, Barcelona, Spain.
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González Quijada S, Grande Sáez MC, Dueñas Gutiérrez C, Ceballos Barón MI, Martín Ezquerro A, Sevil Puras M, Blanco García M. [Cardiovascular and hormonal factors associated with the lack of nocturnal fall in blood pressure among individuals aged over 55]. Rev Clin Esp 2002; 202:264-8. [PMID: 12060540 DOI: 10.1016/s0014-2565(02)71048-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND Usually, there is a physiological fall in nocturnal blood pressure among all individuals, both hypertensive and normotensive individuals. The lack of nocturnal blood pressure (BP) fall may be associated with the risk of developing cardiovascular complications in hypertensive patients. Cardiovascular and hormonal factors associated with the lack of nocturnal blood pressure fall was studied in individuals aged over 55, those most exposed to this kind of complications. METHODS A total of 108 individuals aged over 55 and with a wide range of BP (59 normotensive and 49 light-moderate hypertensive with no previous treatment) were studied. Two groups were established: dipper and non-dipper, with a fall over 10% in nocturnal SBP and DBP or not, respectively. Patients included in the study underwent serum hormonal measurements (renin, aldosterone, endoteline-1, atrial natriuretic peptide, free epinephrine and norepinephrine), continuous blood pressure monitoring for 24 hours (CBPM) and echocardiography with measurement of left ventricular mass (LVM), cardiac output, and peripheral vascular resistances (PVR) (determined in function of mean blood pressure and cardiac output). RESULTS Fifty-one individuals were dipper and 57 were non-dipper. Significantly higher cholesterol (p < 0.05) and free norepinephrine (p < 0.001) levels among dipper compared with non-dipper individuals were observed. Non-dipper individuals had PVR significantly higher than dipper individuals (p < 0.05). Values of diurnal BP, other hormonal measurements, and CBPM did not differ significantly between the two groups. CONCLUSIONS Non-dipper individuals aged over 55 have lower circulating free norepinephrine values and higher peripheral vascular resistances than dipper individuals, irrespective of diurnal blood pressure values. The left ventricular mass does not differ significantly between the two groups.
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Turner SW, Fraser TB, Mangos GJ, Whitworth JA. Circadian blood pressure variability in adrenocorticotrophin-induced hypertension in the rat. J Hypertens 2001; 19:1411-9. [PMID: 11518849 DOI: 10.1097/00004872-200108000-00009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Secondary hypertension is often characterized by loss of diurnal blood pressure variability. This study examined circadian (24 h) blood pressure variability in adrenocorticotrophin (ACTH)-induced hypertension in the Sprague-Dawley rat. METHODS Male Sprague-Dawley rats were randomly allocated to sham (0.9% saline, s.c.), n = (9), ACTH (0.5 microg/kg per day, s.c., n = 8) or ACTH (100 microg/kg per day, s.c., n = 7) in a room with a 12 h light/dark cycle (0600 h to 1800 h). A radio telemetry transducer was used to measure blood pressure in unrestrained animals over 3 control days (C1-C3) and 10 treatment days (T1-T10). Heart rate, systolic (SBP), mean arterial (MAP) and diastolic (DBP) blood pressure were continuously recorded. Body weight was measured daily and serum corticosterone concentration ([B]) prior to death. RESULTS Sham treatment had no effect on any parameters. ACTH 100 microg/kg per day increased SBP from 124+/-2 pooled control (PC) to 134+/-2 mmHg (T10), MAP from 105+/-2 to 115+/-2 mmHg and DBP from 87+/-1 to 99+/-2 mmHg and decreased heart rate from 305+/-6 to 249+/-5 beats/min and body weight from 299+/-6 (C3) to 280+/-8 g (T10) (all P' < 0.0036). Serum [B] was higher in ACTH- (881+/-44 ng/ml) than sham-treated rats (384+/-17 ng/ml, P < 0.001). There were no differences between sham treatment and ACTH 0.5 microg/kg per day. SBP, MAP, DBP and heart rate were consistently higher for ACTH 100 microg/kg per day and sham-treated animals during the dark cycle (1800 h to 0600 h) than the light cycle (0600 h to 1800 h). CONCLUSIONS ACTH 100 microg/kg per day raises blood pressure in conscious unrestrained Sprague-Dawley rats without any change in normal diurnal rhythm.
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Affiliation(s)
- S W Turner
- Department of Medicine, The St George Hospital, The University of New South Wales, Sydney, Australia
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Fang Z, Carlson SH, Peng N, Wyss JM. Circadian rhythm of plasma sodium is disrupted in spontaneously hypertensive rats fed a high-NaCl diet. Am J Physiol Regul Integr Comp Physiol 2000; 278:R1490-5. [PMID: 10848515 DOI: 10.1152/ajpregu.2000.278.6.r1490] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
High-NaCl diets elevate arterial pressure in NaCl-sensitive individuals, and increases in plasma sodium may trigger this effect. The present study tests the hypotheses that 1) plasma sodium displays a circadian rhythm in rats, 2) the plasma sodium rhythm is disturbed in spontaneously hypertensive rats (SHR), and 3) excess dietary NaCl elevates plasma sodium concentration in SHR. The results demonstrate that plasma sodium has a circadian rhythm that is inversely related to the circadian rhythm of arterial pressure. Although the plasma sodium rhythms of SHR and control rats are nearly identical, the plasma sodium concentrations are significantly higher in SHR throughout the 24-h cycle. Maintenance on a high-NaCl diet increases plasma sodium concentration similarly in both SHR and control rats, but it blunts the plasma sodium rhythm only in SHR. These results demonstrate that in rats, plasma sodium has a circadian rhythm and that high-NaCl diets increase plasma sodium concentration.
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Affiliation(s)
- Z Fang
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0019, USA
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