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Fang P, Li X, Shan H, Saredy JJ, Cueto R, Xia J, Jiang X, Yang XF, Wang H. Ly6C + Inflammatory Monocyte Differentiation Partially Mediates Hyperhomocysteinemia-Induced Vascular Dysfunction in Type 2 Diabetic db/db Mice. Arterioscler Thromb Vasc Biol 2019; 39:2097-2119. [PMID: 31366217 PMCID: PMC6761027 DOI: 10.1161/atvbaha.119.313138] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Hyperhomocysteinemia (HHcy) is a potent risk factor for diabetic cardiovascular diseases. We have previously reported that hyperhomocysteinemia potentiates type 1 diabetes mellitus-induced inflammatory monocyte differentiation, vascular dysfunction, and atherosclerosis. However, the effects of hyperhomocysteinemia on vascular inflammation in type 2 diabetes mellitus (T2DM) and the underlying mechanism are unknown. Approach and Results: Here, we demonstrate that hyperhomocysteinemia was induced by a high methionine diet in control mice (homocysteine 129 µmol/L), which was further worsened in T2DM db/db mice (homocysteine 180 µmol/L) with aggravated insulin intolerance. Hyperhomocysteinemia potentiated T2DM-induced mononuclear cell, monocyte, inflammatory monocyte (CD11b+Ly6C+), and M1 macrophage differentiation in periphery and aorta, which were rescued by folic acid-based homocysteine-lowering therapy. Moreover, hyperhomocysteinemia exacerbated T2DM-impaired endothelial-dependent aortic relaxation to acetylcholine. Finally, transfusion of bone marrow cells depleted for Ly6C by Ly6c shRNA transduction improved insulin intolerance and endothelial-dependent aortic relaxation in hyperhomocysteinemia+T2DM mice. CONCLUSIONS Hyperhomocysteinemia potentiated systemic and vessel wall inflammation and vascular dysfunction partially via inflammatory monocyte subset induction in T2DM. Inflammatory monocyte may be a novel therapeutic target for insulin resistance, inflammation, and cardiovascular complications in hyperhomocysteinemia+T2DM.
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Affiliation(s)
- Pu Fang
- Center for Metabolic Disease Research, Lewis Kats School of Medicine, Temple University, Philadelphia, PA
| | - Xinyuan Li
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia PA
| | - Huimin Shan
- Center for Metabolic Disease Research, Lewis Kats School of Medicine, Temple University, Philadelphia, PA
| | - Jason J Saredy
- Center for Metabolic Disease Research, Lewis Kats School of Medicine, Temple University, Philadelphia, PA
| | - Ramon Cueto
- Center for Metabolic Disease Research, Lewis Kats School of Medicine, Temple University, Philadelphia, PA
| | - Jixiang Xia
- Center for Metabolic Disease Research, Lewis Kats School of Medicine, Temple University, Philadelphia, PA
| | - Xiaohua Jiang
- Center for Metabolic Disease Research, Lewis Kats School of Medicine, Temple University, Philadelphia, PA
| | - Xiao-Feng Yang
- Center for Metabolic Disease Research, Lewis Kats School of Medicine, Temple University, Philadelphia, PA
- Department of Pharmacology, Lewis Kats School of Medicine, Temple University, Philadelphia, PA
| | - Hong Wang
- Center for Metabolic Disease Research, Lewis Kats School of Medicine, Temple University, Philadelphia, PA
- Department of Pharmacology, Lewis Kats School of Medicine, Temple University, Philadelphia, PA
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Cheng Z, Shen X, Jiang X, Shan H, Cimini M, Fang P, Ji Y, Park JY, Drosatos K, Yang X, Kevil CG, Kishore R, Wang H. Hyperhomocysteinemia potentiates diabetes-impaired EDHF-induced vascular relaxation: Role of insufficient hydrogen sulfide. Redox Biol 2018. [PMID: 29524844 PMCID: PMC5854893 DOI: 10.1016/j.redox.2018.02.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Insufficient hydrogen sulfide (H2S) has been implicated in Type 2 diabetic mellitus (T2DM) and hyperhomocysteinemia (HHcy)-related cardiovascular complications. We investigated the role of H2S in T2DM and HHcy-induced endothelial dysfunction in small mesenteric artery (SMA) of db/db mice fed a high methionine (HM) diet. HM diet (8 weeks) induced HHcy in both T2DM db/db mice and non-diabetic db/+ mice (total plasma Hcy: 48.4 and 31.3 µM, respectively), and aggravated the impaired endothelium-derived hyperpolarization factor (EDHF)-induced endothelium-dependent relaxation to acetylcholine (ACh), determined by the presence of eNOS inhibitor N(ω)-nitro-L-arginine methyl ester (L-NAME) and prostacyclin (PGI2) inhibitor indomethacin (INDO), in SMA from db/db mice but not that from db/+ mice. A non-selective Ca2+-active potassium channel (KCa) opener NS309 rescued T2DM/HHcy-impaired EDHF-mediated vascular relaxation to ACh. EDHF-induced relaxation to ACh was inhibited by a non-selective KCa blocker TEA and intermediate-conductance KCa blocker (IKCa) Tram-34, but not by small-conductance KCa (SKCa) blocker Apamin. HHcy potentiated the reduction of free sulfide, H2S and cystathionine γ-lyase protein, which converts L-cysteine to H2S, in SMA of db/db mice. Importantly, a stable H2S donor DATS diminished the enhanced O2- production in SMAs and lung endothelial cells of T2DM/HHcy mice. Antioxidant PEG-SOD and DATS improved T2DM/HHcy impaired relaxation to ACh. Moreover, HHcy increased hyperglycemia-induced IKCa tyrosine nitration in human micro-vascular endothelial cells. EDHF-induced vascular relaxation to L-cysteine was not altered, whereas such relaxation to NaHS was potentiated by HHcy in SMA of db/db mice which was abolished by ATP-sensitive potassium channel blocker Glycolamide but not by KCa blockers. Conclusions Intermediate HHcy potentiated H2S reduction via CSE-downregulation in microvasculature of T2DM mice. H2S is justified as an EDHF. Insufficient H2S impaired EDHF-induced vascular relaxation via oxidative stress and IKCa inactivation in T2DM/HHcy mice. H2S therapy may be beneficial for prevention and treatment of micro-vascular complications in patients with T2DM and HHcy.
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Affiliation(s)
- Zhongjian Cheng
- Center for Translational Medicine, Lewis Katz School of Medicine, Temple University, 3500 Broad Street, Philadelphia, PA 19140, USA.
| | - Xinggui Shen
- Center for Cardiovascular Diseases and Sciences, Department of Pathology, Molecular and Cellular Physiology and Cell Biology and Anatomy Louisiana State University Health Sciences Center-Shreveport, New Orleans, LA 7110371103, USA
| | - Xiaohua Jiang
- Center for Metabolic Disease Research, Lewis Katz School of Medicine, Temple University, 3500 Broad Street, Philadelphia, PA 19140, USA
| | - Huimin Shan
- Center for Metabolic Disease Research, Lewis Katz School of Medicine, Temple University, 3500 Broad Street, Philadelphia, PA 19140, USA
| | - Maria Cimini
- Center for Translational Medicine, Lewis Katz School of Medicine, Temple University, 3500 Broad Street, Philadelphia, PA 19140, USA
| | - Pu Fang
- Center for Metabolic Disease Research, Lewis Katz School of Medicine, Temple University, 3500 Broad Street, Philadelphia, PA 19140, USA
| | - Yong Ji
- Key Laboratory of Cardiovascular Disease and Molecular Intervention, Nanjing Medical University, Nanjing 210029, China
| | - Joon Young Park
- Cardiovascular Research Center, Lewis Katz School of Medicine, Temple University, 3500 Broad Street, Philadelphia, PA 19140, USA
| | - Konstantinos Drosatos
- Center for Metabolic Disease Research, Lewis Katz School of Medicine, Temple University, 3500 Broad Street, Philadelphia, PA 19140, USA; Center for Translational Medicine, Lewis Katz School of Medicine, Temple University, 3500 Broad Street, Philadelphia, PA 19140, USA; Department of Pharmacology, Lewis Katz School of Medicine, Temple University, 3500 Broad Street, Philadelphia, PA 19140, USA
| | - Xiaofeng Yang
- Center for Metabolic Disease Research, Lewis Katz School of Medicine, Temple University, 3500 Broad Street, Philadelphia, PA 19140, USA; Cardiovascular Research Center, Lewis Katz School of Medicine, Temple University, 3500 Broad Street, Philadelphia, PA 19140, USA; Department of Pharmacology, Lewis Katz School of Medicine, Temple University, 3500 Broad Street, Philadelphia, PA 19140, USA
| | - Christopher G Kevil
- Center for Cardiovascular Diseases and Sciences, Department of Pathology, Molecular and Cellular Physiology and Cell Biology and Anatomy Louisiana State University Health Sciences Center-Shreveport, New Orleans, LA 7110371103, USA
| | - Raj Kishore
- Center for Translational Medicine, Lewis Katz School of Medicine, Temple University, 3500 Broad Street, Philadelphia, PA 19140, USA; Department of Pharmacology, Lewis Katz School of Medicine, Temple University, 3500 Broad Street, Philadelphia, PA 19140, USA
| | - Hong Wang
- Center for Metabolic Disease Research, Lewis Katz School of Medicine, Temple University, 3500 Broad Street, Philadelphia, PA 19140, USA; Cardiovascular Research Center, Lewis Katz School of Medicine, Temple University, 3500 Broad Street, Philadelphia, PA 19140, USA; Department of Pharmacology, Lewis Katz School of Medicine, Temple University, 3500 Broad Street, Philadelphia, PA 19140, USA.
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Su JB. Vascular endothelial dysfunction and pharmacological treatment. World J Cardiol 2015; 7:719-741. [PMID: 26635921 PMCID: PMC4660468 DOI: 10.4330/wjc.v7.i11.719] [Citation(s) in RCA: 127] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 06/23/2015] [Accepted: 09/18/2015] [Indexed: 02/06/2023] Open
Abstract
The endothelium exerts multiple actions involving regulation of vascular permeability and tone, coagulation and fibrinolysis, inflammatory and immunological reactions and cell growth. Alterations of one or more such actions may cause vascular endothelial dysfunction. Different risk factors such as hypercholesterolemia, homocystinemia, hyperglycemia, hypertension, smoking, inflammation, and aging contribute to the development of endothelial dysfunction. Mechanisms underlying endothelial dysfunction are multiple, including impaired endothelium-derived vasodilators, enhanced endothelium-derived vasoconstrictors, over production of reactive oxygen species and reactive nitrogen species, activation of inflammatory and immune reactions, and imbalance of coagulation and fibrinolysis. Endothelial dysfunction occurs in many cardiovascular diseases, which involves different mechanisms, depending on specific risk factors affecting the disease. Among these mechanisms, a reduction in nitric oxide (NO) bioavailability plays a central role in the development of endothelial dysfunction because NO exerts diverse physiological actions, including vasodilation, anti-inflammation, antiplatelet, antiproliferation and antimigration. Experimental and clinical studies have demonstrated that a variety of currently used or investigational drugs, such as angiotensin-converting enzyme inhibitors, angiotensin AT1 receptors blockers, angiotensin-(1-7), antioxidants, beta-blockers, calcium channel blockers, endothelial NO synthase enhancers, phosphodiesterase 5 inhibitors, sphingosine-1-phosphate and statins, exert endothelial protective effects. Due to the difference in mechanisms of action, these drugs need to be used according to specific mechanisms underlying endothelial dysfunction of the disease.
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Effects of late-onset and long-term captopril and nifedipine treatment in aged spontaneously hypertensive rats: Echocardiographic studies. Hypertens Res 2015; 38:716-22. [DOI: 10.1038/hr.2015.68] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 03/19/2015] [Accepted: 04/09/2015] [Indexed: 11/08/2022]
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Hyperhomocysteinemia impairs endothelium-derived hyperpolarizing factor-mediated vasorelaxation in transgenic cystathionine beta synthase-deficient mice. Blood 2011; 118:1998-2006. [PMID: 21653942 DOI: 10.1182/blood-2011-01-333310] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Hyperhomocysteinemia (HHcy) is associated with endothelial dysfunction (ED), but the mechanism is largely unknown. In this study, we investigated the role and mechanism of HHcy-induced ED in microvasculature in our newly established mouse model of severe HHcy (plasma total homocysteine, 169.5 μM). We found that severe HHcy impaired nitric oxide (NO)- and endothelium-derived hyperpolarizing factor (EDHF)-mediated, endothelium-dependent relaxations of small mesenteric arteries (SMAs). Endothelium-independent and prostacyclin-mediated endothelium-dependent relaxations were not changed. A nonselective Ca(2+)-activated potassium channel (K(Ca)) inhibitor completely blocked EDHF-mediated relaxation. Selective blockers for small-conductance K(Ca) (SK) or intermediate-conductance K(Ca) (IK) failed to inhibit EDHF-mediated relaxation in HHcy mice. HHcy increased the levels of SK3 and IK1 protein, superoxide (O(2)(-)), and 3-nitrotyrosine in the endothelium of SMAs. Preincubation with antioxidants and peroxynitrite (ONOO(-)) inhibitors improved endothelium-dependent and EDHF-mediated relaxations and decreased O(2)(-) production in SMAs from HHcy mice. Further, EDHF-mediated relaxation was inhibited by ONOO(-) and prevented by catalase in the control mice. Finally, L-homocysteine stimulated O(2)(-) production, which was reversed by antioxidants, and increased SK/IK protein levels and tyrosine nitration in cultured human cardiac microvascular endothelial cells. Our results suggest that HHcy impairs EDHF relaxation in SMAs by inhibiting SK/IK activities via oxidation- and tyrosine nitration-related mechanisms.
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Ernsberger P, Koletsky RJ. Metabolic effects of antihypertensive agents: role of sympathoadrenal and renin-angiotensin systems. Naunyn Schmiedebergs Arch Pharmacol 2006; 373:245-58. [PMID: 16783586 DOI: 10.1007/s00210-006-0080-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2006] [Accepted: 05/09/2006] [Indexed: 01/01/2023]
Abstract
Reports of beneficial, neutral and adverse impacts of antihypertensive drug classes on glucose and lipid metabolism can be found in human data. Furthermore, mechanisms for these diverse effects are often speculative and controversial. Clinical trial data on the metabolic effects of antihypertensive agents are highly contradictory. Comparisons of clinical trials involving different agents are complicated by differences in the spectrum of metabolic disturbances that accompany hypertension in different groups of patients. Two physiological systems are predominant at the interface between metabolic and cardiovascular regulation: the sympathetic nervous system (SNS) and the renin-angiotensin system (RAS). These two systems are major targets of antihypertensive drug actions, and also mediate many of the beneficial and adverse effects of antihypertensive agents on glucose and lipid metabolism. Thiazides and beta-adrenergic antagonists can adversely affect glucose and lipid metabolism, which are frequently compromised in human essential hypertension, and increase the incidence of new cases of diabetes. Laboratory studies confirm these effects, and suggest that compensatory activation of the SNS and RAS may be one mechanism. Other antihypertensives directly targeting the SNS and RAS may have beneficial effects on glucose and lipid metabolism, and may prevent diabetes. Resolution of the controversies surrounding the metabolic effects of antihypertensive agents can only be resolved by further laboratory studies, in addition to controlled clinical trials.
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Jeffery TK, Wanstall JC. Pulmonary vascular remodelling in hypoxic rats: effects of amlodipine, alone and with perindopril. Eur J Pharmacol 2001; 416:123-31. [PMID: 11282121 DOI: 10.1016/s0014-2999(01)00855-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
This study investigated whether pulmonary vascular remodelling in hypoxic pulmonary hypertensive rats (10% oxygen; 4 weeks) could be prevented by treatment, during hypoxia, with amlodipine (10 mg/kg/day, p.o.), either alone or in combination with the angiotensin converting enzyme inhibitor, perindopril (30 mg/kg/day, p.o.). Medial thickening of pulmonary arteries (30-500 microm o.d.) was attenuated by amlodipine whereas it was totally prevented by the combination treatment (amlodipine plus perindopril); neomuscularisation of small alveolar arteries (assessed from critical closing pressure in isolated perfused lungs) was not affected. Pulmonary vascular resistance (isolated perfused lungs) was reduced by both treatment regimes but only combination treatment reduced right ventricular hypertrophy. Thus, amlodipine has anti-remodelling properties in pulmonary hypertensive rats. The finding that combining amlodipine with another anti-remodelling drug produced effects on vascular structure that were additive raises the question of whether combination therapy with two different anti-remodelling drugs may be of value in the treatment of patients with hypoxic (and possibly other forms of) pulmonary hypertension.
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Affiliation(s)
- T K Jeffery
- Pulmonary Pharmacology Group, Department of Physiology and Pharmacology, The University of Queensland, St Lucia, Qld 4072, Brisbane, Australia
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Cheng ZJ, Vaskonen T, Tikkanen I, Nurminen K, Ruskoaho H, Vapaatalo H, Muller D, Park JK, Luft FC, Mervaala EM. Endothelial dysfunction and salt-sensitive hypertension in spontaneously diabetic Goto-Kakizaki rats. Hypertension 2001; 37:433-9. [PMID: 11230314 DOI: 10.1161/01.hyp.37.2.433] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Endothelial dysfunction is associated with hypertension, hypercholesterolemia, and heart failure. We tested the hypothesis that spontaneously diabetic Goto-Kakizaki (GK) rats, a model for type 2 diabetes, exhibit endothelial dysfunction. Rats also received a high-sodium diet (6% NaCl [wt/wt]) and chronic angiotensin type 1 (AT(1)) receptor blockade (10 mg/kg PO valsartan for 8 weeks). Compared with age-matched nondiabetic Wistar control rats, GK rats had higher blood glucose levels (9.3+/-0.5 versus 6.9+/-0.2 mmol/L for control rats), 2.7-fold higher serum insulin levels, and impaired glucose tolerance (all P<0.05). Telemetry-measured mean blood pressure was 15 mm Hg higher in GK rats (P<0.01) compared with control rats, whereas heart rates were not different. Heart weight- and kidney weight-to-body weight ratios were higher in GK rats (P<0.05), and 24-hour albuminuria was increased 50%. Endothelium-mediated relaxation of noradrenaline-precontracted mesenteric arterial rings by acetylcholine was impaired compared with the control condition (P<0.05), whereas the sodium nitroprusside-induced relaxation was similar. Preincubation of the arterial rings with the NO synthase inhibitor N(G)-nitro-L-arginine methyl ester and the cyclooxygenase inhibitor diclofenac inhibited relaxations to acetylcholine almost completely in GK rats but not in Wistar rats, suggesting that endothelial dysfunction can be in part attributed to reduced relaxation via arterial K(+) channels. Perivascular monocyte/macrophage infiltration and intercellular adhesion molecule-1 overexpression were observed in GK rat kidneys. A high-sodium diet increased blood pressure by 24 mm Hg and 24-hour albuminuria by 350%, induced cardiac hypertrophy, impaired endothelium-dependent relaxation further, and aggravated inflammation (all P<0.05). The serum level of 8-isoprostaglandin F(2alpha), a vasoconstrictor and antinatriuretic arachidonic acid metabolite produced by oxidative stress, was increased 400% in GK rats on a high-sodium diet. Valsartan decreased blood pressure in rats fed a low-sodium diet and prevented the inflammatory response. In rats fed a high-sodium diet, valsartan did not decrease blood pressure or improve endothelial dysfunction but protected against albuminuria, inflammation, and oxidative stress. As measured by quantitative autoradiography, AT(1) receptor expression in the medulla was decreased in GK compared with Wistar rats, whereas cortical AT(1) receptor expression, medullary and cortical angiotensin type 2 (AT(2)) receptor expressions, and adrenal ACE and neutral endopeptidase expressions were unchanged. A high-sodium diet did not influence renal AT(1), AT(2), ACE, or neutral endopeptidase expressions. In valsartan-treated GK rats, the cortical and medullary AT(1) receptor expressions were decreased in the presence and absence of a high-sodium diet. A high-sodium diet increased plasma brain natriuretic peptide concentrations in presence and absence of valsartan treatment. We conclude that hypertension in GK rats is salt sensitive and associated with endothelial dysfunction and perivascular inflammation. AT(1) receptor blockade ameliorates inflammation during a low-sodium diet and partially protects against salt-induced vascular damage by blood pressure-independent mechanisms.
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MESH Headings
- Acetylcholine
- Angiotensin Receptor Antagonists
- Animals
- Blood Pressure/drug effects
- Diabetes Mellitus, Type 1/complications
- Diabetes Mellitus, Type 1/physiopathology
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/physiopathology
- Heart Rate/drug effects
- Hypertension/complications
- Hypertension/physiopathology
- In Vitro Techniques
- Mesenteric Arteries/drug effects
- Neprilysin/metabolism
- Nitroprusside
- Norepinephrine
- Peptidyl-Dipeptidase A/metabolism
- Rats
- Rats, Wistar
- Receptor, Angiotensin, Type 1
- Receptor, Angiotensin, Type 2
- Receptors, Angiotensin/metabolism
- Sodium, Dietary/administration & dosage
- Tetrazoles/pharmacology
- Valine/analogs & derivatives
- Valine/pharmacology
- Valsartan
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Affiliation(s)
- Z J Cheng
- Institute of Biomedicine, Department of Pharmacology and Toxicology, University of Helsinki, Helsinki, Finland
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Abstract
In this review, we attempt to outline the age-dependent interactions of principal systems controlling the structure and function of the cardiovascular system in immature rats developing hypertension. We focus our attention on the cardiovascular effects of various pharmacological, nutritional, and behavioral interventions applied at different stages of ontogeny. Several distinct critical periods (developmental windows), in which particular stimuli affect the further development of the cardiovascular phenotype, are specified in the rat. It is evident that short-term transient treatment of genetically hypertensive rats with certain antihypertensive drugs in prepuberty and puberty (at the age of 4-10 wk) has long-term beneficial effects on further development of their cardiovascular apparatus. This juvenile critical period coincides with the period of high susceptibility to the hypertensive effects of increased salt intake. If the hypertensive process develops after this critical period (due to early antihypertensive treatment or late administration of certain hypertensive stimuli, e.g., high salt intake), blood pressure elevation, cardiovascular hypertrophy, connective tissue accumulation, and end-organ damage are considerably attenuated compared with rats developing hypertension during the juvenile critical period. As far as the role of various electrolytes in blood pressure modulation is concerned, prohypertensive effects of dietary Na+ and antihypertensive effects of dietary Ca2+ are enhanced in immature animals, whereas vascular protective and antihypertensive effects of dietary K+ are almost independent of age. At a given level of dietary electrolyte intake, the balance between dietary carbohydrate and fat intake can modify blood pressure even in rats with established hypertension, but dietary protein intake affects the blood pressure development in immature animals only. Dietary protein restriction during gestation, as well as altered mother-offspring interactions in the suckling period, might have important long-term hypertensive consequences. The critical periods (developmental windows) should be respected in the future pharmacological or gene therapy of human hypertension.
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Affiliation(s)
- J Zicha
- Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
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Pourageaud F, Hamon G, Freslon JL. Trandolapril treatment at low dose improves mechanical and functional properties in perfused coronary arteries of spontaneously hypertensive rat. Fundam Clin Pharmacol 1999; 13:300-9. [PMID: 10392306 DOI: 10.1111/j.1472-8206.1999.tb00349.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The ex-vivo effects of a 1-month treatment period with trandolapril at a low dose (0.3 mg/kg/day) were assessed on the mechanical and functional alterations observed in SHR coronary arteries. The in-vitro intrinsic elastic properties of the wall in treated SHR coronary arteries were determined in comparison to those of SHR rats. In preconstricted preparations, agonist- and flow-induced dilatations were investigated in arteries of both groups. Arterial segments were cannulated at both ends using an arteriograph system. Internal diameter and wall thickness were continuously monitored while intraluminal pressure and flow were controlled. Wall thickness was reduced in arteries of treated rats compared to those in control SHR (mm): 52 +/- 2 vs. 41 +/- 2, P < 0.001, respectively. Arterial stiffness, expressed by the incremental elastic modulus-stress relationship, was significantly lower in arteries of treated compared to control SHRs. In preconstricted preparations, dilatations induced by bradykinin were significantly greater in treated SHR compared to control SHR arteries whereas dilatations induced by acetylcholine were slightly but not significantly increased. On the other hand, starting flow at the plateau of 5-HT-induced constriction led to dilatations which were not significantly different in the treated compared to the control group. The maximal dilatation induced by flow in arteries of treated rats was obtained for the same value of shear stress compared to that determined in preparations of control SHRs: (dyn/cm2) 63 +/- 3 vs. 61 +/- 2, respectively, NS. These results show that together with hypertrophy, the abnormal mechanical properties observed in the coronary arterial wall of SHR were improved by a low dose of trandolapril treatment. However, differential effects of trandolapril treatment were observed on agonist and flow-induced dilatations. Although flow-induced dilatation seemed to remain unaffected, acetylcholine-induced dilatation was slightly improved and bradykinin-induced dilatation was markedly increased by trandolapril treatment.
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Affiliation(s)
- F Pourageaud
- Department of Pharmacology, Faculty of Pharmacy, University Victor-Segalen Bordeaux II, France
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12
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Ozdem SS, Oğütman C. The effects of short-term nifedipine treatment on responsiveness of aortic rings of cadmium-hypertensive rats. Clin Exp Hypertens 1999; 21:423-40. [PMID: 10369384 DOI: 10.3109/10641969909068674] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The effects of short-term antihypertensive treatment with nifedipine on blood pressure and vascular responsiveness were studied in cadmium-hypertensive and normotensive control rats. Cadmium administration caused a significant increase in mean arterial blood pressure. Endothelin-1, noradrenaline and angiotensin II produced concentration dependent contractions of aortic rings that attained a lower maximal contraction in cadmium-hypertensive rats. Responses of aortic rings to KCl did not show a significant difference between the groups. Nifedipine administered simultaneously with cadmium inhibited the induction of hypertension. Nifedipine treatment for 5 days significantly reduced the blood pressure in cadmium-hypertensive and normotensive rats. Neither inhibition of hypertension nor normalization of blood pressure in cadmium-hypertensive rats caused an alteration in contractile responses of aortic rings to vasoconstrictors which suggested that development of decreased vascular reactivity and of hypertension occurs simultaneously in cadmium-hypertensive rats but the role of decreased vascular reactivity in maintenance of hypertension is questionable in cadmium-hypertension.
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Affiliation(s)
- S S Ozdem
- Department of Pharmacology, Medical Faculty of Akdeniz University, Antalya, Turkey.
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Mervaala EM, Malmberg L, Teräväinen TL, Laakso J, Vapaatalo H, Karppanen H. Influence of dietary salts on the cardiovascular effects of low-dose combination of ramipril and felodipine in spontaneously hypertensive rats. Br J Pharmacol 1998; 123:195-204. [PMID: 9489606 PMCID: PMC1565153 DOI: 10.1038/sj.bjp.0701591] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
1 In spontaneously hypertensive rat (SHR) we examined over a 4-week period the influence of control low sodium diet, common salt-enriched diet (sodium chloride 6% of the dry weight of the chow) and a novel mineral salt-enriched diet (potassium-, magnesium-, and l-lysine-enriched mineral salt added at a 75% higher level of 10.5% to produce the same sodium chloride concentration of 6%) on the cardiovascular effects produced by a low-dose combination of an angiotensin converting enzyme inhibitor ramipril (0.25 mg kg(-1) day(-1) in the food) and a calcium channel blocker felodipine (0.4 mg kg(-1) day(-1) subcutaneously via an osmotic minipump). 2 Common salt, but not the mineral salt, accelerated the development of hypertension and induced left ventricular and renal hypertrophy in SHR. Neither common salt nor mineral salt significantly affected heart rate. 3 The combination of ramipril and felodipine decreased systolic blood pressure and prevented the development of left ventricular hypertrophy effectively during the common salt diet without any significant effect on the heart rate. The cardiovascular effects of the drug combination were improved by the low sodium diet or by replacement of high common salt in the diet by mineral salt. 4 Responses of endothelium-intact mesenteric arterial rings in vitro were examined at the end of the four-week study. The combination of ramipril and felodipine markedly improved the endothelium-dependent vascular relaxation responses to acetylcholine and enhanced the endothelium-independent vascular relaxation responses to sodium nitroprusside in SHR on control and common salt diets. Replacement of common salt in the diet by mineral salt improved the endothelium-dependent vascular relaxation responses to acetylcholine. The drug combination attenuated the alpha-adrenoceptor-mediated vascular contractile responses to noradrenaline during the common salt diet. 5 Ramipril and felodipine in combination increased plasma renin activity by 1.9-3.2 fold without affecting serum aldosterone levels. 6 Our findings suggest that the cardiovascular effect of the low-dose combination of ramipril and felodipine was maintained during high salt intake. However, salt restriction or replacement of common salt in the diet by the potassium- and magnesium-enriched mineral salt improved the cardiovascular effects of the drug combination. In the face of a high intake of sodium, a part of the beneficial cardiovascular effects of the drug combination is apparently mediated by improved endothelium-dependent and endothelium-independent vascular relaxation responses and attenuated alpha-adrenoceptor-mediated vascular contractile responses.
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Affiliation(s)
- E M Mervaala
- Institute of Biomedicine, Department of Pharmacology and Toxicology, University of Helsinki, Finland
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