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- Tarp, Julie Bjerre, et al.
(author)
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Subclinical atherosclerosis in patients with cyanotic congenital heart disease
- 2019
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In: International Journal of Cardiology. - : Elsevier BV. - 0167-5273 .- 1874-1754. ; 277, s. 97-103
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Journal article (peer-reviewed)abstract
- Introduction: Survival in patients with cyanotic congenital heart disease (CCHD) has improved dramatically. The result is an ageing population with risk of acquired heart disease. Previous small uncontrolled studies suggested that these patients are protected against the development of atherosclerosis. To test this hypothesis, we sought to determine the prevalence of subclinical atherosclerosis in a larger population of patients with CCHD. Method: We compared the prevalence of subclinical atherosclerosis in adult CCHD patients from Denmark, Sweden, Norway and Australia, with that in age-, sex-, smoking status-, and body mass index matched controls. Coronary artery atherosclerosis was assessed on computed tomography with coronary artery calcification (CAC) score. Subclinical atherosclerosis was defined by CAC-score > 0. Carotid artery atherosclerosis was evaluated using ultrasound by measuring carotid plaque thickness (cPT-max) and carotid intima media thickness (CIMT). Lipid status was evaluated as an important atherosclerotic risk factor. Results: Seventy-four patients with CCHD (57% women, median age 49.5 years) and 74 matched controls (57% women, median age 50.0 years) were included. There were no differences between the groups in: CAC-score > 0 (21% vs. 19%, respectively; p = 0.8), carotid plaques (19% vs. 9%, respectively; p = 0.1), cPT-max (2.3 mm vs. 2.8 mm, respectively; p = 0.1) or CIMT (0.61 mm vs. 0.61 mm, respectively; p = 0.98). And further no significant differences in lipoprotein concentrations measured by ultracentrifugation. Conclusion: Young adults with CCHD have similar cardiovascular risk factor profiles and measures of subclinical atherosclerosis, compared with controls. Given their increasing life expectancies, athero-preventive strategies should be an important part of their clinical management.
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| 2. |
- Tarp, Julie Bjerre, et al.
(author)
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Vascular function in adults with cyanotic congenital heart disease
- 2020
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In: IJC Heart and Vasculature. - : Elsevier BV. - 2352-9067. ; 30
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Journal article (peer-reviewed)abstract
- Background: Patients with cyanotic congenital heart disease (CCHD) may have a low burden of atherosclerosis. Endothelial dysfunction is an early stage of atherosclerosis and endothelial function is previously studied in smaller CCHD groups with different techniques and variable results. We aimed to examine endothelial function and carotid atherosclerosis in a larger group of CCHD patients. Methods: This multicentre study assessed endothelial function in adults with CCHD and controls by measuring the dilatory response of the brachial artery to post-ischemic hyperaemia (endothelium-dependent flow-mediated-vasodilatation (FMD)), and to nitroglycerin (endothelium-independent nitroglycerin-induced dilatation (NID)). Flow was measured at baseline and after ischaemia (reactive hyperaemia). Carotid-intima-media-thickness (CIMT), prevalence of carotid plaque and plaque thickness (cPT-max) were evaluated ultrasonographically. Lipoproteins, inflammatory and vascular markers, including sphingosine-1-phosphate (S1P) were measured. Results: Forty-five patients with CCHD (median age 50 years) and 45 matched controls (median age 52 years) were included. The patients presented with lower reactive hyperaemia (409 ± 114% vs. 611 ± 248%, p < 0.0001), however preserved FMD response compared to controls (106.5 ± 8.3% vs. 106.4 ± 6.1%, p = 0.95). In contrast, NID was lower in the patients (110.5 ± 6.1% vs. 115.1 ± 7.4%, p = 0.053). There was no difference in CIMT, carotid plaque or cPT-max. The patients presented with lower high-density-lipoprotein cholesterol, and higher level of inflammatory markers and S1P. Conclusion: Adults with CCHD had preserved FMD in the brachial artery, but impaired NID response and lower reactive hyperaemia than controls. The preserved FMD and the comparable prevalence of carotid atherosclerosis indicate that CCHD patients have the same risk of atherosclerosis as controls.
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| 3. |
- Jacobsen, Jens Christian Brings, et al.
(author)
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A model of smooth muscle cell synchronization in the arterial wall.
- 2007
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In: American journal of physiology. Heart and circulatory physiology. - : American Physiological Society. - 0363-6135 .- 1522-1539. ; 293:1
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Journal article (peer-reviewed)abstract
- Vasomotion is a rhythmic variation in microvascular diameter. Although known for more than 150 years, the cellular processes underlying the initiation of vasomotion are not fully understood. In the present study a model of a single cell is extended by coupling a number of cells into a tube. The simulated results point to a permissive role of cGMP in establishing intercellular synchronization. In sufficient concentration, cGMP may activate a cGMP-sensitive calcium-dependent chloride channel, causing a tight spatiotemporal coupling between release of sarcoplasmic reticulum calcium, membrane depolarization, and influx of extracellular calcium. Low [cGMP] is associated only with unsynchronized waves. At intermediate concentrations, cells display either waves or whole cell oscillations, but these remain unsynchronized between cells. Whole cell oscillations are associated with rhythmic variation in membrane potential and flow of current through gap junctions. The amplitude of these oscillations in potential grows with increasing [cGMP], and, past a certain threshold, they become strong enough to entrain all cells in the vascular wall, thereby initiating sustained vasomotion. In this state there is a rhythmic flow of calcium through voltage-sensitive calcium channels into the cytoplasm, making the frequency of established vasomotion sensitive to membrane potential. It is concluded that electrical coupling through gap junctions is likely to be responsible for the rapid synchronization across a large number of cells. Gap-junctional current between cells is due to the appearance of oscillations in the membrane potential that again depends on the entrainment of sarcoplasmic reticulum and plasma membrane within the individual cell.
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| 4. |
- Jacobsen, Jens Christian Brings, et al.
(author)
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Activation of a cGMP-sensitive calcium-dependent chloride channel may cause transition from calcium waves to whole cell oscillations in smooth muscle cells.
- 2007
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In: American journal of physiology. Heart and circulatory physiology. - : American Physiological Society. - 0363-6135 .- 1522-1539. ; 293:1
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Journal article (peer-reviewed)abstract
- In vitro, alpha-adrenoreceptor stimulation of rat mesenteric small arteries often leads to a rhythmic change in wall tension, i.e., vasomotion. Within the individual smooth muscle cells of the vascular wall, vasomotion is often preceded by a period of asynchronous calcium waves. Abruptly, these low-frequency waves may transform into high-frequency whole cell calcium oscillations. Simultaneously, multiple cells synchronize, leading to rhythmic generation of tension. We present a mathematical model of vascular smooth muscle cells that aims at characterizing this sudden transition. Simulations show calcium waves sweeping through the cytoplasm when the sarcoplasmic reticulum (SR) is stimulated to release calcium. A rise in cGMP leads to the experimentally observed transition from waves to whole cell calcium oscillations. At the same time, membrane potential starts to oscillate and the frequency approximately doubles. In this transition, the simulated results point to a key role for a recently discovered cGMP-sensitive calcium-dependent chloride channel. This channel depolarizes the membrane in response to calcium released from the SR. In turn, depolarization causes a uniform opening of L-type calcium channels on the cell surface, stimulating a synchronized release of SR calcium and inducing the shift from waves to whole cell oscillations. The effect of the channel is therefore to couple the processes of the SR with those of the membrane. We hypothesize that the shift in oscillatory mode and the associated onset of oscillations in membrane potential within the individual cell may underlie sudden intercellular synchronization and the appearance of vasomotion.
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| 5. |
- Jacobsen, Jens Christian Brings, et al.
(author)
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Heterogeneity and weak coupling may explain the synchronization characteristics of cells in the arterial wall.
- 2008
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In: Philosophical transactions. Series A, Mathematical, physical, and engineering sciences. - : The Royal Society. - 1364-503X. ; 366:1880, s. 3483-502
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Journal article (peer-reviewed)abstract
- Vascular smooth muscle cells (SMCs) exhibit different types of calcium dynamics. Static vascular tone is associated with unsynchronized calcium waves and the developed force depends on the number of recruited cells. Global calcium transients synchronized among a large number of cells cause rhythmic development of force known as vasomotion. We present experimental data showing a considerable heterogeneity in cellular calcium dynamics in the vascular wall. In stimulated vessels, some SMCs remain quiescent, whereas others display waves of variable frequency. At the onset of vasomotion, all SMCs are enrolled into synchronized oscillation.Simulations of coupled SMCs show that the experimentally observed cellular recruitment, the presence of quiescent cells and the variation in oscillation frequency may arise if the cell population is phenotypically heterogeneous. In this case, quiescent cells can be entrained at the onset of vasomotion by the collective driving force from the synchronized oscillations in the membrane potential of the surrounding cells. Partial synchronization arises with an increase in the concentration of cyclic guanosine monophosphate, but in a heterogeneous cell population complete synchronization also requires a high-conductance pathway that provides strong coupling between the cells.
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