Circadian Variations in Blood Pressure, Heart Rate, and HR-BP Cross-Correlation Coefficient during Progression of Diabetes Mellitus in Rat

Anigbogu, C.N.; Williams, Daniel T.; Brown, David R.; Silcox, Dennis L.; Speakman, Richard O.; Brown, Lynsey; Karounos, Dennis G.; Randall, David C.

doi:10.4061/2011/738689

Cited by 8 publications

(5 citation statements)

References 26 publications

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“…In an animal model of type 1 diabetes mellitus, a phase shift was observed by the 2nd diabetic month in which the diurnal blood pressure peak shifted from the midafternoon to late afternoon but the amplitude of the rhythm was reduced. In the ninth month, there was a significant reduction in cross-correlation coefficient (by computational cross-correlation coefficient analysis of changes in HR and BP) and a phase shift in the peaks and dips that could mark the beginning of irreversible impairment of autonomic and cardiovascular function [61]. Similarly, humans with type 1 diabetes mellitus showed DBP ecphasia that was more pronounced in patients with lower HR variability [50].…”

Section: What Are the Adverse Consequences That May Results From An Almentioning

confidence: 97%

“…In Dahl salt-sensitive rats, calorie overload was associated with significant increase in: body weight, fasting glucose, concentrations of leptin, adiponectin, and pro-inflammatory cytokines; in addition, dysglycemic rats exhibited significantly elevated circadian overall mean SBP, DBP, and HR [60]. Circadian changes in cardiovascular function were found also in animal models of type 1 diabetes [61]. The disease seemed to alter mean BP and HR control much earlier than expected based on structural changes in the vasculature or autonomic nerves, possibly due to early consequences on myocardial function and metabolism; weakening of the initial pressor response to an acute stress as the duration of the disease approaches 1 year is consonant with the progression of diabetic dysautonomia [62].…”

Section: Evidence For Altered Characteristics Of Blood Pressure Rhythmentioning

confidence: 88%

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Circadian Rhythm of Blood Pressure in Diabetes Mellitus: Evidence, Mechanisms and Implications

Matteucci

Giampietro²

2012

CDR

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Circadian misalignment has been implicated in the development of diabetes mellitus and cardiovascular disease. Circadian rhythms of blood pressure (BP) and heart rate (HR) have long been known and the mechanisms controlling them have been actively investigated in physiology and disease. In this respect, the introduction of 24-hour ambulatory blood pressure monitoring (ABPM) has enabled a more accurate assessment of circadian BP patterns in order to solve diagnostic uncertainty or to establish dipper status. However, attention has been mainly focused on measures of extent (midline estimating statistic of rhythm, MESOR, and amplitude) rather than timing (acrophase) of changes within a cycle. The review summarises 1) evidence for altered characteristics of BP rhythm (in particular, phase shifts along the time axis) in animal and human diabetes mellitus, 2) the mechanisms that have been supposed to underlie the observed changes in cardiovascular function before diabetes onset and during progression of the disease, and 3) the adverse consequences that may result from an altered circadian BP rhythm.

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Section: What Are the Adverse Consequences That May Results From An Almentioning

confidence: 97%

Section: Evidence For Altered Characteristics Of Blood Pressure Rhythmentioning

confidence: 88%

Circadian Rhythm of Blood Pressure in Diabetes Mellitus: Evidence, Mechanisms and Implications

Matteucci

Giampietro²

2012

CDR

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“…These included: 1) a phase shift by the second diabetic month in which the diurnal blood pressure peak shifted from the mid-afternoon to late-afternoon but the amplitude of the rhythm was reduced, and 2) a phase shift in the peaks and dips (with the night-time having the lowest dip) by the ninth month that could mark the beginning of irreversible impairment of autonomic and cardiovascular function. 25 Analogously, patients with type 1 diabetes mellitus showed diastolic blood pressure ecphasia that was more pronounced in those with lower heart rate variability. 14 Furthermore, in longitudinal studies using animal models of hypertension, an increase in the circadian amplitude of blood pressure preceded MESOR hypertension, 26 just as observed in non-diabetic siblings of type 1 diabetic patients who showed signs of reduced insulin sensitivity associated with a circadian hyper-amplitude-tension.…”

Section: Glossarymentioning

confidence: 99%

Ambulatory Blood Pressure Monitoring and Circadian Rhythm of Blood Pressure in Diabetes Mellitus

Matteucci

Giampietro

2013

EMJ Diabet

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Systolic and diastolic blood pressures display a circadian rhythmicity that can be assessed by 24-hour ambulatory blood pressure monitoring and analysed using the cosinor procedure. Altered characteristics to the circadian rhythm of blood pressure, which may result in adverse health outcomes, have been observed in both prediabetes and diabetes. We have investigated the circadian variability of blood pressure in patients with type 1 and type 2 diabetes. Chronobiologically interpreted ambulatory blood pressure monitoring uncovered not only midline estimating statistic of rhythm (MESOR)-hypertension and circadian hyper-amplitude-tension, but also circadian ecphasia (an odd timing of the daily blood pressure swing). Diastolic blood pressure acrophases were found to be phase shifted to earlier along the time axis only in patients with diabetes, but not in those with essential hypertension. Several mechanisms, from changes in nutrient-dependent signalling pathways to diabetic autonomic neuropathy, can contribute to alterations of circadian time structures in diabetic people. The chronology of blood pressure changes in animal models of diabetes and hypertension suggests that a chronobiological approach to the diagnosis of blood pressure disorders could offer advantages, but longitudinal studies in humans are needed to determine its potential relevance in hypertension associated with diabetes.

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“…13 The possibility offered by radiotelemetry of recording parameters in conscious and untethered animals rules out various artifacts and drawbacks generated by drugs and/or gas anesthesia such as respiratory and cardiovascular depression. Radiotelemetry has also allowed the investigation of circadian blood pressure variability 14,15 or circadian changes in body temperature. 16,17 Accordingly, we also observed changes in RVP, HR and activity of rabbits related to light exposure, with an increase in RVP, HR and activity during the dark cycle, corresponding to the typical nocturnal activity of prey animals.…”

Section: Discussionmentioning

confidence: 99%

Measurement of right ventricular pressure by telemetry in conscious moving rabbits

2013

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Implantable radiotelemetry methodology has been used to continuously monitor pulmonary hemodynamics including right ventricular pressure (RVP) or pulmonary arterial pressure (PAP) in conscious, untethered and freely moving animals such as mice and rats. The use of implantable radiotelemetry to monitor RVP or PAP has never previously been described in rabbits. The aim of the present study was to use implantable radiotelemetry to continuously monitor RVP in conscious adult rabbits. Telemetry transmitters were implanted in 44 adult male New Zealand rabbits using a trans-diaphragm approach for the catheter placement. RVP, heart rate (HR) and activity were monitored every 15 min for 20 s. Body mass was recorded once a week. A total of 39 (88%) rabbits were successfully implanted. Thirty rabbits survived the surgical procedure resulting in an overall survival rate of 73%. RVP, HR and activity were long-term monitored in 17 rabbits for an average period of 103 AE 15 days. Weekly body mass follow-up showed that implantable radiotelemetry did not impair the normal development of the animal. Twenty-four-hour period monitoring of RVP, HR and activity showed concomitant changes in RVP, HR and activity according to the dark/light cycle applied to the rabbits. To conclude, implantable radiotelemetry methodology can be safely used to continuously monitor RVP in conscious rabbits. KeywordsTelemetry, right ventricular pressure, pulmonary circulation, rabbit Pulmonary hypertension is a medical condition mainly affecting the pulmonary circulation. Various rodent animal models have been developed to better understand the physiopathology of pulmonary hypertension and to test potential new drugs.1 Hemodynamic data from these animal models are usually restricted to a single measurement of pulmonary arterial pressure (PAP) and/or right ventricular pressure (RVP), in anesthetized, mechanically ventilated and often openchest animals.2,3 More recently, high-resolution echocardiography and magnetic resonance imaging (MRI) techniques have been developed to accurately estimate hemodynamics in small animals including rats, mice and rabbits, and to allow for serial monitoring of experimental pulmonary hypertension.4,5 Although these techniques are non-invasive, they are performed on anesthetized animals, which implies respiratory and cardiovascular depression resulting in various artifacts. Continuous monitoring of RVP and PAP in conscious, untethered and freely moving animals was introduced by Hess et al. in the 1990s and has consequently and considerably improved hemodynamic pulmonary measurement in rodent models of pulmonary hypertension. 6 Since then, telemetry has been widely described as a method for measuring RVP and PAP in rodent models of pulmonary hypertension.7-10 However, the original procedure of implantable radiotelemetry methodology included extremely invasive thoracic surgery resulting in significant stress, potentially disturbing the cardiovascular system, and in delayed recovery. More recently, a trans-diaphragm surgi...

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Circadian Variations in Blood Pressure, Heart Rate, and HR-BP Cross-Correlation Coefficient during Progression of Diabetes Mellitus in Rat

Cited by 8 publications

References 26 publications

Circadian Rhythm of Blood Pressure in Diabetes Mellitus: Evidence, Mechanisms and Implications

Circadian Rhythm of Blood Pressure in Diabetes Mellitus: Evidence, Mechanisms and Implications

Ambulatory Blood Pressure Monitoring and Circadian Rhythm of Blood Pressure in Diabetes Mellitus

Measurement of right ventricular pressure by telemetry in conscious moving rabbits

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