-
1.
Dihydropyridine Calcium Channel Blockers and the Risk of Severe COVID-19.
Mendez, SR, Frank, RC, Stevenson, EK, Chung, M, Silverman, MG
Chest. 2021;(1):89-93
-
2.
Role of Rho in Salt-Sensitive Hypertension.
Kawarazaki, W, Fujita, T
International journal of molecular sciences. 2021;(6)
Abstract
A high amount of salt in the diet increases blood pressure (BP) and leads to salt-sensitive hypertension in individuals with impaired renal sodium excretion. Small guanosine triphosphatase (GTP)ase Rho and Rac, activated by salt intake, play important roles in the pathogenesis of salt-sensitive hypertension as key switches of intracellular signaling. Focusing on Rho, high salt intake in the central nervous system increases sodium concentrations of cerebrospinal fluid in salt-sensitive subjects via Rho/Rho kinase and renin-angiotensin system activation and causes increased brain salt sensitivity and sympathetic nerve outflow in BP control centers. In vascular smooth muscle cells, Rho-guanine nucleotide exchange factors and Rho determine sensitivity to vasoconstrictors such as angiotensin II (Ang II), and facilitate vasoconstriction via G-protein and Wnt pathways, leading to increased vascular resistance, including in the renal arteries, in salt-sensitive subjects with high salt intake. In the vascular endothelium, Rho/Rho kinase inhibits nitric oxide (NO) production and function, and high salt amounts further augment Rho activity via asymmetric dimethylarginine, an endogenous inhibitor of NO synthetase, causing aberrant relaxation and increased vascular tone. Rho-associated mechanisms are deeply involved in the development of salt-sensitive hypertension, and their further elucidation can help in developing effective protection and new therapies.
-
3.
Aldosterone Induces Vasoconstriction in Individuals with Type 2 Diabetes: Effect of Acute Antioxidant Administration.
Finsen, SH, Hansen, MR, Hansen, PBL, Mortensen, SP
The Journal of clinical endocrinology and metabolism. 2021;(3):e1262-e1270
Abstract
CONTEXT Individuals with type 2 diabetes have an increased risk of endothelial dysfunction and cardiovascular disease. Plasma aldosterone could contribute by reactive oxygen species-dependent mechanisms by inducing a shift in the balance between a vasoconstrictor and vasodilator response to aldosterone. OBJECTIVE We aimed to investigate the acute vascular effects of aldosterone in individuals with type 2 diabetes compared with healthy controls and if infusion of an antioxidant (n-acetylcysteine [NAC]) would alter the vascular response. METHODS In a case-control design, 12 participants with type 2 diabetes and 14 healthy controls, recruited from the general community, were studied. Leg hemodynamics were measured before and during aldosterone infusion (0.2 and 5 ng min-1 [L leg volume]-1) for 10 minutes into the femoral artery with and without coinfusion of NAC (125 mg kg-1 hour-1 followed by 25 mg kg-1 hour-1). Leg blood flow and arterial blood pressure was measured, and femoral arterial and venous blood samples were collected. RESULTS Compared with the control group, leg blood flow and vascular conductance decreased during infusion of aldosterone at the high dose in individuals with type 2 diabetes, whereas coinfusion of NAC attenuated this response. Plasma aldosterone increased in both groups during aldosterone infusion and there was no difference between groups at baseline or during the infusions. CONCLUSION These results suggests that type 2 diabetes is associated with a vasoconstrictor response to physiological levels of infused aldosterone and that the antioxidant NAC diminishes this response.
-
4.
A Paradoxical Vasodilatory Nutraceutical Intervention for Prevention and Attenuation of Migraine-A Hypothetical Review.
Chaliha, DR, Vaccarezza, M, Takechi, R, Lam, V, Visser, E, Drummond, P, Mamo, JCL
Nutrients. 2020;(8)
Abstract
Studies suggest that migraine pain has a vascular component. The prevailing dogma is that peripheral vasoconstriction activates baroreceptors in central, large arteries. Dilatation of central vessels stimulates nociceptors and induces cortical spreading depression. Studies investigating nitric oxide (NO) donors support the indicated hypothesis that pain is amplified when acutely administered. In this review, we provide an alternate hypothesis which, if substantiated, may provide therapeutic opportunities for attenuating migraine frequency and severity. We suggest that in migraines, heightened sympathetic tone results in progressive central microvascular constriction. Suboptimal parenchymal blood flow, we suggest, activates nociceptors and triggers headache pain onset. Administration of NO donors could paradoxically promote constriction of the microvasculature as a consequence of larger upstream central artery vasodilatation. Inhibitors of NO production are reported to alleviate migraine pain. We describe how constriction of larger upstream arteries, induced by NO synthesis inhibitors, may result in a compensatory dilatory response of the microvasculature. The restoration of central capillary blood flow may be the primary mechanism for pain relief. Attenuating the propensity for central capillary constriction and promoting a more dilatory phenotype may reduce frequency and severity of migraines. Here, we propose consideration of two dietary nutraceuticals for reducing migraine risk: L-arginine and aged garlic extracts.
-
5.
[Role of Ca2+ in hypoxic pulmonary vasoconstriction].
Wei, G, Cheng, Y, Huang, Y, He, Q
Zhonghua wei zhong bing ji jiu yi xue. 2019;(5):647-649
Abstract
In acute hypoxia, pulmonary vascular will contract and divert blood to better ventilated area to optimize ventilation/perfusion matching, which is known as hypoxic pulmonary vasoconstriction (HPV). In chronic hypoxia, irreversible pulmonary vascular remodeling can be induced, characterized by pulmonary artery middle smooth muscle cells and the outer fiber cell hyperplasia in luminal stenosis and pulmonary artery hypertension (PAH) eventually. Furthermore, PAH can cause increased ventricular afterload, and right heart failure in severe cases. Pulmonary artery smooth muscle cell (PASMC) elevated Ca2+ concentration is one of the most important factors of its contractions, proliferation and migration. Recent studies on Ca2+ promoting in HPV were summarized in order to provide evidence for clinical prevention of hypoxia and therapeutic PAH.
-
6.
Effect of acute dietary nitrate supplementation on sympathetic vasoconstriction at rest and during exercise.
de Vries, CJ, DeLorey, DS
Journal of applied physiology (Bethesda, Md. : 1985). 2019;(1):81-88
Abstract
Dietary nitrate ( NO3- ) supplementation has been shown to reduce resting blood pressure. However, the mechanism responsible for the reduction in blood pressure has not been identified. Dietary NO3- supplementation may increase nitric oxide (NO) bioavailability, and NO has been shown to inhibit sympathetic vasoconstriction in resting and contracting skeletal muscle. Therefore, the purpose of this study was to investigate the hypothesis that acute dietary NO3- supplementation would attenuate sympathetic vasoconstrictor responsiveness at rest and during exercise. In a double-blind randomized crossover design, 12 men (23 ± 5 yr) performed a cold-pressor test (CPT) at rest and during moderate- and heavy-intensity alternate-leg knee-extension exercise after consumption of NO3- rich beetroot juice (~12.9 mmol NO3- ) or a NO3- -depleted placebo (~0.13 mmol NO3- ). Venous blood was sampled before and 2.5 h after the consumption of beetroot juice for the measurement of total plasma nitrite/ NO3- [NOx]. Beat-by-beat blood pressure was measured by Finometer. Leg blood flow was measured at the femoral artery via Doppler ultrasound, and leg vascular conductance (LVC) was calculated. Sympathetic vasoconstrictor responsiveness was calculated as the percentage decrease in LVC in response to the CPT. Total plasma [NOx] was greater (P < 0.001) in the NO3- (285 ± 120 µM) compared with the placebo (65 ± 30 µM) condition. However, mean arterial blood pressure and plasma catecholamines were not different (P > 0.05) between NO3- and placebo conditions at rest or during moderate- and heavy-intensity exercise. Sympathetic vasoconstrictor responsiveness (Δ% LVC) was not different (P > 0.05) between NO3- and placebo conditions at rest ( NO3- : -33 ± 10%; placebo: -35 ± 11%) or during moderate ( NO3- : -18 ± 8%; placebo: -20 ± 10%)- and heavy ( NO3- : -12 ± 8%; placebo: -11 ± 9%)-intensity exercise. These data demonstrate that acute dietary NO3- supplementation does not alter sympathetic vasoconstrictor responsiveness at rest or during exercise in young healthy males. NEW & NOTEWORTHY Dietary nitrate may increase nitric oxide bioavailability, and nitric oxide has been shown to attenuate sympathetic vasoconstriction in resting and contracting skeletal muscle and enhance functional sympatholysis. However, the effect of dietary nitrate on sympathetic vasoconstrictor responsiveness is unknown. Acute dietary nitrate supplementation did not alter blood pressure or sympathetic vasoconstrictor responsiveness at rest or during exercise in young healthy males.
-
7.
Docosahexaenoic acid reduces resting blood pressure but increases muscle sympathetic outflow compared with eicosapentaenoic acid in healthy men and women.
Lee, JB, Notay, K, Klingel, SL, Chabowski, A, Mutch, DM, Millar, PJ
American journal of physiology. Heart and circulatory physiology. 2019;(4):H873-H881
Abstract
Supplementation with monounsaturated or ω-3 polyunsaturated fatty acids ( n-3 PUFA) can lower resting blood pressure (BP) and reduce the risk of cardiovascular events. The independent contributions of the n-3 PUFAs eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on BP, and the mechanisms responsible, are unclear. We tested whether EPA, DHA, and olive oil (OO), a source of monounsaturated fat, differentially affect resting hemodynamics and muscle sympathetic nerve activity (MSNA). Eighty-six healthy young men and women were recruited to participate in a 12-wk, randomized, double-blind trial examining the effects of orally supplementing ~3 g/day of EPA ( n = 28), DHA ( n = 28), or OO ( n = 30) on resting hemodynamics; MSNA was examined in a subset of participants ( n = 31). Both EPA and DHA supplements increased the ω-3 index ( P < 0.01). Reductions in systolic BP were greater [adjusted intergroup mean difference (95% confidence interval)] after DHA [-3.4 mmHg (-0.9, -5.9), P = 0.008] and OO [-3.0 mmHg (-0.5, -5.4), P = 0.01] compared with EPA, with no difference between DHA and OO ( P = 0.74). Reductions in diastolic BP were greater following DHA [-3.4 mmHg (-1.3,-5.6), P = 0.002] and OO [-2.2 mmHg (0.08,-4.3), P = 0.04] compared with EPA. EPA increased heart rate compared with DHA [4.2 beats/min (-0.009, 8.4), P = 0.05] and OO [4.2 beats/min, (0.08, 8.3), P = 0.04]. MSNA burst frequency was higher after DHA [4 bursts/min (0.5, 8.3), P = 0.02] but not OO [-3 bursts/min (-6, 0.6), P = 0.2] compared with EPA. Overall, DHA and OO evoked similar responses in resting BP; however, DHA, but not OO, increased peripheral vasoconstrictor outflow. These findings may have implications for fatty acid supplementation in clinical populations characterized by chronic high BP and sympathetic overactivation. NEW & NOTEWORTHY We studied the effects of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and olive oil supplementation on blood pressure (BP) and muscle sympathetic nerve activity (MSNA). After 12 wk of 3 g/day supplementation, DHA and olive oil were associated with lower resting systolic and diastolic BPs than EPA. However, DHA increased MSNA compared with EPA. The reductions in BP with DHA likely occur via a vascular mechanism and evoke a baroreflex-mediated increase in sympathetic activity.
-
8.
Use of levosimendan in the treatment of cerebral vascular vasospasm: a case study.
Onichimowski, D, Nosek, K, Goraj, R, Jalali, R, Wińska, A, Pawlos, A, Tuyakov, B
Drug design, development and therapy. 2018;:1777-1783
Abstract
Despite the progress in the management of cerebral arterial aneurysms, subarachnoid hemorrhage (SAH) remains the major cause of neurological disability. While SAH-related deaths usually occur as a result of brain impairment due to hemorrhage, permanent neurological deficits are caused by cerebral ischemia due to edema and spasm of cerebral arteries. Additionally, ~20%-30% of patients with SAH develop secondary cardiomyopathy; this phenomenon is known as neurogenic stress cardiomyopathy (NSC), which is associated with increased mortality and poor long-term prognosis. Levosimendan is a new inotropic drug that causes calcium sensitization of troponin C, thus increasing contraction force of myofilaments. The drug also causes opening of ATP-dependent potassium channels in vascular smooth muscles, which results in dilatation of veins and arteries, including cerebral arteries. To date, there have been several reports of levosimendan application in patients with SAH and neurogenic stress cardiomyopathy, and the effect of the drug on vasospasm has been previously advocated. This paper presents a case report of a 57-year-old patient with massive SAH, where levosimendan was used for reducing vasospasm.
-
9.
How is the human umbilical artery regulated?
Lorigo, M, Mariana, M, Feiteiro, J, Cairrao, E
The journal of obstetrics and gynaecology research. 2018;(7):1193-1201
Abstract
The purpose of this review is to present an update of the main mechanisms involved in the physiological regulation of contraction and relaxation of the human umbilical artery (HUA) smooth muscle cells. A literature review was performed based on the analysis of papers available on PubMed. The most important and relevant studies regarding the regulation of the HUA are presented in this article. The vascular smooth muscle is a highly specialized structure, whose main function is to regulate the vascular tonus. This is controlled by a balance between the cellular signaling pathways that mediate contraction and relaxation. The cells responsible for the contractile property of this muscle are the smooth muscle cells (SMC), and an excellent source of these cells is the HUA, involved in fetoplacental circulation. Since the umbilical blood vessels are not innervated, the HUA tonus is modulated by vasoactive substances that regulate the contractile process. The main vasoactive substances that induce contraction are serotonin, histamine, thromboxane, bradykinin, endothelin 1 and prostaglandin F2α, that are linked to the activation of proteins Gq and Gi/0 . On the other hand, the main vasorelaxation mechanisms are the activation of adenyl and guanil cyclases, potassium channels and the inhibition of calcium channels. The SMC from the HUA allow the study of different cellular mechanisms and their functions. Therefore, these cells are an important tool to study the mechanisms regulating the contractility of this artery, allowing to detect potential therapeutic targets to treat HUA disorders (gestational hypertension and pre-eclampsia).
-
10.
Impaired vasocontractile responses to adenosine in chorionic vessels of human term placenta from pregnant women with pre-existing and gestational diabetes.
Razak, AA, Leach, L, Ralevic, V
Diabetes & vascular disease research. 2018;(6):528-540
Abstract
BACKGROUND There is clinical and experimental evidence for altered adenosine signalling in the fetoplacental circulation in pregnancies complicated by diabetes, leading to adenosine accumulation in the placenta. However, the consequence for fetoplacental vasocontractility is unclear. This study examined contractility to adenosine of chorionic vessels from type 1 diabetes mellitus, gestational diabetes mellitus and normal pregnancies. METHODS Chorionic arteries and veins were isolated from human placenta from normal, gestational diabetes mellitus and type 1 diabetes mellitus pregnancies. Isometric tension recording measured responses to adenosine and the thromboxane A2 analogue U46619 (thromboxane A2 mediates fetoplacental vasoconstriction to adenosine). Adenosine and thromboxane prostanoid receptor protein expression was determined by immunoblotting. RESULTS Adenosine elicited contractions in chorionic arteries and veins which were impaired in both gestational diabetes mellitus and type 1 diabetes mellitus. Contractions to potassium chloride were unchanged. Adenosine A2A and A2B receptor protein levels were not different in gestational diabetes mellitus and normal pregnancies. Contractions to U46619 were unaltered in gestational diabetes mellitus arteries and increased in type 1 diabetes mellitus arteries. Overnight storage of vessels restored contractility to adenosine in gestational diabetes mellitus arteries and normalized contraction to U46619 in type 1 diabetes mellitus arteries. CONCLUSION These data are consistent with the concept of aberrant adenosine signalling in diabetes; they show for the first time that this involves impaired adenosine contractility of the fetoplacental vasculature.