Non-symmetrical double-logistic analysis of 24 hour arterial stiffness profile in normotensive and hypertensive subjects

Bia, Daniel; Armentano, Ricardo; Pessana, Franco; Zócalo, Yanina; Lluberas, Sebastián; Avolio, Alberto

doi:10.1109/iembs.2008.4649277

Cited by 5 publications

(5 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Clinically, this increased VSMC membrane potential translates to a higher basal tone of the thoracic aorta. This will further result in increased aortic stiffness, as indicated by both experimental (Fridez et al, 2001; Gao et al, 2014; Leloup et al, 2016) and clinical studies (Wilkinson et al, 2002; Bia et al, 2008). The results of this study further indicate that basal NO release mainly affects NSCC-mediated contractions, but seemed to be preload-independent.…”

Section: Discussionmentioning

confidence: 97%

Isometric Stretch Alters Vascular Reactivity of Mouse Aortic Segments

et al. 2017

View full text Add to dashboard Cite

Most vaso-reactive studies in mouse aortic segments are performed in isometric conditions and at an optimal preload, which is the preload corresponding to a maximal contraction by non-receptor or receptor-mediated stimulation. In general, this optimal preload ranges from about 1.2 to 8.0 mN/mm, which according to Laplace's law roughly correlates with transmural pressures of 10–65 mmHg. For physiologic transmural pressures around 100 mmHg, preloads of 15.0 mN/mm should be implemented. The present study aimed to compare vascular reactivity of 2 mm mouse (C57Bl6) aortic segments preloaded at optimal (8.0 mN/mm) vs. (patho) physiological (10.0–32.5 mN/mm) preload. Voltage-dependent contractions of aortic segments, induced by increasing extracellular K+, and contractions by α1-adrenergic stimulation with phenylephrine (PE) were studied at these preloads in the absence and presence of L-NAME to inhibit basal release of NO from endothelial cells (EC). In the absence of basal NO release and with higher than optimal preload, contractions evoked by depolarization or PE were attenuated, whereas in the presence of basal release of NO PE-, but not depolarization-induced contractions were preload-independent. Phasic contractions by PE, as measured in the absence of external Ca2+, were decreased at higher than optimal preload suggestive for a lower contractile SR Ca2+ content at physiological preload. Further, in the presence of external Ca2+, contractions by Ca2+ influx via voltage-dependent Ca2+ channels were preload-independent, whereas non-selective cation channel-mediated contractions were increased. The latter contractions were very sensitive to the basal release of NO, which itself seemed to be preload-independent. Relaxation by endogenous NO (acetylcholine) of aortic segments pre-contracted with PE was preload-independent, whereas relaxation by exogenous NO (diethylamine NONOate) displayed higher sensitivity at high preload. Results indicated that stretching aortic segments to higher than optimal preload depolarizes the SMC and causes Ca2+ unloading of the contractile SR, making them extremely sensitive to small changes in the basal release of NO from EC as can occur in hypertension or arterial stiffening.

show abstract

Section: Discussionmentioning

confidence: 97%

Isometric Stretch Alters Vascular Reactivity of Mouse Aortic Segments

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Another study on the circadian changes in arterial stiffness showed a paradoxical increase in arterial stiffness at night, while BP dropped, serving as another indication that the active changes in large artery wall properties can modulate large artery biomechanics (Bia et al. ), aside from the passive changes due to blood pressure alone.…”

Section: Discussionmentioning

confidence: 99%

Vascular smooth muscle cell contraction and relaxation in the isolated aorta: a critical regulator of large artery compliance

et al. 2019

View full text Add to dashboard Cite

Over the past few decades, isometric contraction studies of isolated thoracic aorta segments have significantly contributed to our overall understanding of the active, contractile properties of aortic vascular smooth muscle cells ( VSMC s) and their cross‐talk with endothelial cells. However, the physiological role of VSMC contraction or relaxation in the healthy aorta and its contribution to the pulse‐smoothening capacity of the aorta is currently unclear. Therefore, we investigated the acute effects of VSMC contraction and relaxation on the isobaric biomechanical properties of healthy mouse aorta. An in‐house developed set‐up was used to measure isobaric stiffness parameters of periodically stretched (10 Hz) aortic segments at an extended pressure range, while pharmacologically modulating VSMC tone and endothelial cell function. We found that the effects of α1‐adrenergic stimulation with phenylephrine on the pressure‐stiffness relationship varied in sensitivity, magnitude and direction, with the basal, unstimulated NO production by the endothelium playing a pivotal role. We also investigated how arterial disease affected this system by using the angiotensin‐ II ‐treated mouse. Our results show that isobaric stiffness was increased and that the aortic segments demonstrated a reduced capacity for modulating the pressure‐stiffness relationship. This suggests that not only increased isobaric stiffness at normal pressure, but also a reduced capacity of the VSMC s to limit the pressure‐associated increase in aortic stiffness, may contribute to the pathogenesis of this mouse model. Overall, this study provides more insight in how aortic VSMC tone affects the pressure‐dependency of aortic biomechanics at different physiological and pathological conditions.

show abstract

“…Since a steep change of around 20% during day-night transitional periods occurred on the 24-h PTT in healthy subjects [25], the linear interpolations during these periods are therefore inauthentic. To evaluate the correlation between PTT and BP, it is reasonable to remove this nonsystematic error source.…”

Section: ) Rationale For Disregarding Interpolations During Transitimentioning

confidence: 99%

An Armband Wearable Device for Overnight and Cuff-Less Blood Pressure Measurement

Zheng

Yan

Zhang

et al. 2014

IEEE Trans. Biomed. Eng.

152

View full text Add to dashboard Cite

24-h blood pressure (BP) has significant prognostic value for cardiovascular risk screening, but the present BP devices are mainly cuff-based, which are unsuitable for long-term BP measurement, especially during nighttime. In this paper, we developed an armband wearable pulse transit time (PTT) system for 24-h cuff-less BP measurement and evaluated it in an unattended out-of-laboratory setting. Ten healthy young subjects participated in this ambulatory study, where PTT was measured at 30-min interval by this wearable system and the reference BP was measured by a standard oscillometric ambulatory BP monitor. Due to the misalignment of BP and PTT on their recording time caused by the different measurement principles of the two BP devices, a new estimation method has been proposed: transients in PTT were removed from the raw data by defined criteria, and then evenly interpolated, low-pass filtered, and resampled to synchronize at the time when BP was recorded. The results show that with the proposed method, the correlation between PTT and systolic BP (SBP) during nighttime with dynamic range of 21.8 ± 14.2 mmHg has improved from -0.50 ± 0.24 to -0.62 ± 0.20 , and the difference between the estimated and reference SBP has improved from 0.7 ± 10.7 to 2.8 ± 8.2 mmHg with root mean square error reduced from 10.7 to 8.7 mmHg. In addition, the correlation between a very low frequency component of SBP and PTT obtained from the proposed method during nighttime is -0.80 ± 0.10 and the difference is 2.4 ± 5.7 mmHg for a dynamic BP range of 13.5 ± 8.0 mmHg. It is therefore concluded from this study that the proposed wearable system has great potential to be used for overnight SBP monitoring, especially to measure the averaged SBP over a long period.

show abstract

Non-symmetrical double-logistic analysis of 24 hour arterial stiffness profile in normotensive and hypertensive subjects

Cited by 5 publications

References 5 publications

Isometric Stretch Alters Vascular Reactivity of Mouse Aortic Segments

Isometric Stretch Alters Vascular Reactivity of Mouse Aortic Segments

Vascular smooth muscle cell contraction and relaxation in the isolated aorta: a critical regulator of large artery compliance

An Armband Wearable Device for Overnight and Cuff-Less Blood Pressure Measurement

Contact Info

Product

Resources

About