cyclic-gmp and Vascular-Diseases

Vascular cognitive impairment (VCI) describes neurodegenerative disorders characterized by a vascular component. Pathologically, it involves decreased cerebral blood flow (CBF), white matter lesions, endothelial dysfunction, and blood-brain barrier (BBB) impairments. Molecularly, oxidative stress and inflammation are two of the major underlying mechanisms. Nitric oxide (NO) physiologically stimulates soluble guanylate cyclase (sGC) to induce cGMP production. However, under pathological conditions, NO seems to be at the basis of oxidative stress and inflammation, leading to a decrease in sGC activity and expression. The native form of sGC needs a ferrous heme group bound in order to be sensitive to NO (Fe(II)sGC). Oxidation of sGC leads to the conversion of ferrous to ferric heme (Fe(III)sGC) and even heme-loss (apo-sGC). Both Fe(III)sGC and apo-sGC are insensitive to NO, and the enzyme is therefore inactive. sGC activity can be enhanced either by targeting the NO-sensitive native sGC (Fe(II)sGC), or the inactive, oxidized sGC (Fe(III)sGC) and the heme-free apo-sGC. For this purpose, sGC stimulators acting on Fe(II)sGC and sGC activators acting on Fe(III)sGC/apo-sGC have been developed. These sGC agonists have shown their efficacy in cardiovascular diseases by restoring the physiological and protective functions of the NO-sGC-cGMP pathway, including the reduction of oxidative stress and inflammation, and improvement of vascular functioning. Yet, only very little research has been performed within the cerebrovascular system and VCI pathology when focusing on sGC modulation and its potential protective mechanisms on vascular and neural function. Therefore, within this review, the potential of sGC as a target for treating VCI is highlighted.

Topics: Cognitive Dysfunction; Cyclic GMP; Heme; Humans; Inflammation; Soluble Guanylyl Cyclase; Vascular Diseases

The endothelium can evoke relaxations of the underlying vascular smooth muscle, by releasing vasodilator substances. The best-characterized endothelium-derived relaxing factor (EDRF) is nitric oxide (NO) which activates soluble guanylyl cyclase in the vascular smooth muscle cells, with the production of cyclic guanosine monophosphate (cGMP) initiating relaxation. The endothelial cells also evoke hyperpolarization of the cell membrane of vascular smooth muscle (endothelium-dependent hyperpolarizations, EDH-mediated responses). As regards the latter, hydrogen peroxide (H

Topics: Animals; Cyclic GMP; Endothelin-1; Endothelium, Vascular; Humans; Muscle, Smooth, Vascular; Nitric Oxide; Vascular Diseases; Vasoconstriction; Vasodilation

Since the discovery of natriuretic peptides (NPs) by de Bold et al. in 1981, the cardiovascular community has been well aware that they exert potent effects on vessels, heart remodeling, kidney function, and the regulation of sodium and water balance. Who would have thought that NPs are also able to exert metabolic effects and contribute to an original cross talk between heart, adipose tissues, and skeletal muscle? The attention on the metabolic role of NPs was awakened in the year 2000 with the discovery that NPs exert potent lipolytic effects mediated by the NP receptor type A/cGMP pathway in human fat cells and that they contribute to lipid mobilization in vivo. In this review, we will discuss the biological effects of NPs on the main tissues involved in the regulation of energy metabolism (i.e., white and brown adipose tissues, skeletal muscle, liver, and pancreas). These recent results on NPs are opening a new chapter into the physiological properties and therapeutic usefulness of this family of hormones.

Topics: Adipokines; Adipose Tissue; Adipose Tissue, Brown; Animals; Cyclic GMP; Cytokines; Energy Metabolism; Homeostasis; Humans; Lipid Metabolism; Metabolic Diseases; Muscle, Skeletal; Natriuretic Peptides; Signal Transduction; Vascular Diseases

Pathological vascular remodeling is a hallmark of most vascular disorders such as atherosclerosis, postangioplasty restenosis, allograft vasculopathy, and pulmonary hypertension. Pathological vascular remodeling is a multi-cell-dependent process leading to detrimental changes of vessel structure and eventual vessel occlusion. Cyclic nucleotide signaling regulates a variety of vascular functions ranging from cell contractility to cell growth. Cyclic nucleotide phosphodiesterases (PDEs), a large family of structurally and functionally distinct isozymes, regulate cyclic nucleotide levels and compartmentalization through catalyzing their degradation reaction. Increasing evidence has suggested that one of the important mechanisms for specific cyclic nucleotide regulation is exerted through selective activation or inhibition of distinct PDE isozymes. This review summarizes the work done to characterize the role and therapeutic potential of PDE1 isozymes in pathological vascular remodeling.

Topics: Animals; Blood Vessels; Cyclic AMP; Cyclic GMP; Cyclic Nucleotide Phosphodiesterases, Type 1; Humans; Hypertension, Pulmonary; Isoenzymes; Molecular Targeted Therapy; Phosphodiesterase Inhibitors; Vascular Diseases

Cyclic guanosine 3', 5'-monophosphate (cGMP) plays an integral role in the control of vascular function. Generated from guanylate cyclases in response to the endogenous ligands, nitric oxide (NO) and natriuretic peptides (NPs), cGMP influences a number of vascular cell types and regulates vasomotor tone, endothelial permeability, cell growth and differentiation, as well as platelet and blood cell interactions. Reciprocal regulation of the NO-cGMP and NP-cGMP pathways is evident in the vasculature such that one cGMP generating system may compensate for the dysfunction of the other. Indeed, aberrant cGMP production and/or signalling accompanies many vascular disorders such as hypertension, atherosclerosis, coronary artery disease and diabetic complications. This chapter highlights the main vascular functions of cGMP, its role in disease and the resulting current and potential therapeutic applications. With respect to pulmonary hypertension, heart failure and erectile dysfunction, as well as cGMP signal transduction, the reader is specifically referred to other dedicated chapters.

Topics: Animals; Capillary Permeability; Cyclic GMP; Endothelium, Vascular; Humans; Signal Transduction; Vascular Diseases

Topics: Animals; CD47 Antigen; Cyclic GMP; Drug Delivery Systems; Humans; Nitric Oxide; Signal Transduction; Thrombospondin 1; Vascular Diseases

The Natriuretic Peptide (NP) family, especially its best-characterized member Atrial Natriuretic Peptide (ANP), plays an important role in the regulation of blood pressure homeostasis and salt and water balance. Besides their action in cardiovascular physiology, NPs have been described as anti-inflammatory regulators of macrophage function: they have been reported to inhibit the induction of inflammatory mediators, such as iNOS, COX-2, and TNF-alpha. In the following review we will focus on a rather novel aspect of NP action: NPs, especially ANP, will be presented as vasoprotective agents. We will specifically focus on ANP's interaction with the complex intracellular signalling networks responsible for proliferation, vascular permeability, attraction and adhesion of leukocytes, and the induction of cytoprotective proteins. We will also discuss the critical mediator systems involved in mediating ANP's beneficial actions. Recently, ANP as well as BNP, another member of the NP family, have been introduced as cardiovascular therapeutics. In this context, we will highlight the physiological and pharmacological relevance of NPs, particularly ANP, as endogenous vasoprotective agents.

Topics: Animals; Atrial Natriuretic Factor; Capillary Permeability; Cyclic GMP; Cytoprotection; Endothelial Cells; Heat-Shock Proteins; Humans; Leukocyte Disorders; Natriuretic Peptides; Second Messenger Systems; Tumor Necrosis Factor-alpha; Vascular Diseases

The endothelial cells of the vascular system are responsible for many biological activities that maintain vascular homeostasis. Responding to a variety of chemical and physical stimuli, the endothelium elaborates a host of vasoactive agents. One of these agents, endothelium-derived relaxing factor, now accepted as nitric oxide, influences both cellular constituents of the blood and vascular smooth muscle. A principal intracellular target for nitric oxide is guanylate cyclase, which, when activated, increases the intracellular concentration of cyclic guanosine monophosphate, which in turn activates protein kinase G. Acting by this pathway, nitric oxide induces relaxation of vascular smooth muscle and inhibits platelet activation and aggregation. Derangements in endothelial production of nitric oxide are implicated as both cause and consequence of vascular diseases, including hypertension, atherosclerosis, and coronary artery disease.

Topics: Cyclic GMP; Endothelium, Vascular; Humans; Muscle, Smooth, Vascular; Nitric Oxide; Platelet Aggregation Inhibitors; Vascular Diseases; Vasodilation; Vasodilator Agents

Chronic arsenic exposure causes vascular diseases associated with systematic dysfunction of endogenous nitric oxide. Replacement of heavily arsenic-contaminated drinking water with low-arsenic water is a potential intervention strategy for arsenosis, although the reversibility of arsenic intoxication has not established. In the present study, we examined urinary excretion of cyclic guanosine 3 ,5 -monophosphate (cGMP), a second messenger of the vasoactive effects of nitric oxide, and signs and symptoms for peripheral vascular function in 54 arsenosis patients before and after they were supplied with low-arsenic drinking water in an endemic area of chronic arsenic poisoning in Inner Mongolia, China. The arsenosis patients showed a marked decrease in urinary excretion of cGMP (mean +/- SEM: male, 37.0 +/- 6.1; female, 37.2 +/- 5.4 nmol/mmol creatinine), and a 13-month period of consuming low-arsenic drinking water reversed this trend (male, 68.0 +/- 5.6; female, 70.6 +/- 3.0 nmol/mmol creatinine) and improved peripheral vascular response to cold stress. Our intervention study indicates that peripheral vascular disease in arsenosis patients can be reversed by exposure cessation and has important implications for the public health approach to arsenic exposure.

Topics: Adolescent; Adult; Aged; Arsenic Poisoning; Biomarkers; Child; China; Cyclic GMP; Environmental Exposure; Female; Humans; Male; Middle Aged; Nitric Oxide; Public Health; Vascular Diseases; Water Purification; Water Supply

Hyperhomocysteinemia is a risk factor for atherosclerosis and venous thrombosis, probably exerting its effects through endothelial function. Homocysteine levels are lowered by folate supplementation, and such treatment improves endothelial function. However, whether folate supplementation decreases vascular risk and improves survival is unknown. The aim of this study was to evaluate endothelial function and mononuclear leukocyte inflammatory activity during homocysteine lowering in patients with hyperhomocysteinemia and vascular disease.. Endothelial function assessed as plasma (p-)endothelin(ET)-1 and intraplatelet cGMP and cAMP, and mononuclear leukocyte inflammatory activity, assessed as p-neopterin were studied during homocysteine lowering in 50 patients with hyperhomocysteinemia and vascular disease, randomized to folate supplementation or no treatment for 3 months.. P-homocysteine decreased during the 3 months not only in patients on folate supplementation (from 27 [21-52] to 14 [8-41] micromol/l; p<0.001), but also in the untreated group (from 23 [20-35] to 19 [4-31] micromol/l; p<0.001). P-ET-1 decreased during folate supplementation (from 5.7 [2.7-11.6] to 4.1 [1.8-9.0] pg/ml; p<0.01), but was unchanged in the untreated group 4.1 [2.0-9.5] pg/ml and 4.5 [2.7-7.1] pg/ml). P-neopterin was unchanged in patients on folate supplementation (9.7 [5.1-54.4] and 7.6 [5.7-73.0] nmol/l), but increased in the untreated group (from 8.2 [4.7-19.5] to 8.6 [4.6-24.6] nmol/l; p<0.05). Intraplatelet cGMP decreased in patients on folate supplementation (from 0.86 [0.21-2.00] platelets to 0.56 [0.17-1.42] pmol/10(9) platelets; p<0.05), but was unchanged in the untreated group. No significant differences concerning intraplatelet cAMP occurred in either group.. Folate supplementation in hyperhomocysteinemia is associated with decreasing levels of both ET-1 and intraplatelet cGMP, and the absence of an increase in the levels of the inflammatory mediator neopterin.

Topics: Aged; Blood Platelets; Cyclic AMP; Cyclic GMP; Endothelin-1; Female; Folic Acid; Humans; Hyperhomocysteinemia; Male; Neopterin; Vascular Diseases

Cigarette smoke (CS) is associated with vascular injury and dysfunction, which may be mediated by iNOS and NLRP3. However, the exact mechanism is unknown.. iNOS-knockout and NLRP3-knockout C57BL/6 mice were exposed to air or CS. The vascular structure was examined by hematoxylin-eosin staining. The vascular tension was measured by a vascular reactivity assay. The expression of iNOS, NLRP3, caspase-1p20, IL-1β and eNOS were measured by western blotting. Human aortic endothelial cells (HAECs) were exposed to L-NIL (iNOS inhibitor), MCC950 (NLRP3 inhibitor), ODQ (sGC inhibitor), KT5823 (PKG inhibitor) or TAPI-1 (TACE/ADAM17 inhibitor) for 1 h prior to cigarette smoke extract (CSE) treatment. The cell viability and lactate dehydrogenase activity were assessed and pyroptosis was determined by scanning electron microscopy. The mRNA expression of TNF-α, and protein expression of iNOS, active-TACE, NLRP3, caspase-1p20, IL-1β, and eNOS were measured.. CS resulted in shrinkage of endothelial cells, impaired aorta relaxation, reduced eNOS expression, and induced expression of iNOS, NLRP3, caspase-1p20 and IL-1β, which could be prevented by knockdown of iNOS and NLRP3. CSE reduced cell viability, induced LDH release and pyroptosis, and promoted iNOS, NLRP3, caspase-1p20, and IL-1β expression and reduced eNOS reduction, which could be reversed by inhibition of iNOS or NLRP3 in HAECs. Altogether, activation of the NLRP3 inflammasome by iNOS in CS-exposed HAECs may be mediated by the sGC/cGMP/PKG/TACE/TNF- α pathway.. These results link iNOS to NLRP3 in CSE-stimulated HAECs through the sGC/cGMP/PKG/TACE/TNF-α pathway. The findings identify a mechanism through which iNOS and NLRP3 contribute to the pathogenesis of CS-induced pyroptosis and impaired aorta relaxation in HAECs.

Topics: ADAM17 Protein; Animals; Aorta; Cell Line; Cigarette Smoking; Cyclic GMP; Cyclic GMP-Dependent Protein Kinases; Endothelial Cells; Humans; Inflammasomes; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Nitric Oxide Synthase Type II; NLR Family, Pyrin Domain-Containing 3 Protein; Pyroptosis; Signal Transduction; Soluble Guanylyl Cyclase; Tumor Necrosis Factor-alpha; Vascular Diseases

Notch3 mutations cause Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL), which predisposes to stroke and dementia. CADASIL is characterised by vascular dysfunction and granular osmiophilic material (GOM) accumulation in cerebral small vessels. Systemic vessels may also be impacted by Notch3 mutations. However vascular characteristics and pathophysiological processes remain elusive. We investigated mechanisms underlying the peripheral vasculopathy mediated by CADASIL-causing Notch3 gain-of-function mutation. We studied: (i) small arteries and vascular smooth muscle cells (VSMCs) from TgNotch3R169C mice (CADASIL model), (ii) VSMCs from peripheral arteries from CADASIL patients, and (iii) post-mortem brains from CADASIL individuals. TgNotch3R169C vessels exhibited GOM deposits, increased vasoreactivity and impaired vasorelaxation. Hypercontractile responses were normalised by fasudil (Rho kinase inhibitor) and 4-phenylbutyrate (4-PBA; endoplasmic-reticulum (ER) stress inhibitor). Ca2+ transients and Ca2+ channel expression were increased in CADASIL VSMCs, with increased expression of Rho guanine nucleotide-exchange factors (GEFs) and ER stress proteins. Vasorelaxation mechanisms were impaired in CADASIL, evidenced by decreased endothelial nitric oxide synthase (eNOS) phosphorylation and reduced cyclic guanosine 3',5'-monophosphate (cGMP) levels, with associated increased soluble guanylate cyclase (sGC) oxidation, decreased sGC activity and reduced levels of the vasodilator hydrogen peroxide (H2O2). In VSMCs from CADASIL patients, sGC oxidation was increased and cGMP levels decreased, effects normalised by fasudil and 4-PBA. Cerebral vessels in CADASIL patients exhibited significant oxidative damage. In conclusion, peripheral vascular dysfunction in CADASIL is associated with altered Ca2+ homoeostasis, oxidative stress and blunted eNOS/sGC/cGMP signaling, processes involving Rho kinase and ER stress. We identify novel pathways underlying the peripheral arteriopathy induced by Notch3 gain-of-function mutation, phenomena that may also be important in cerebral vessels.

Topics: Animals; Arteries; Brain; CADASIL; Cyclic GMP; Cytoplasmic Granules; Endoplasmic Reticulum Stress; Gain of Function Mutation; Humans; Mice; Mice, Transgenic; Muscle, Smooth, Vascular; Nitric Oxide; Oxidative Stress; Receptor, Notch3; Signal Transduction; Soluble Guanylyl Cyclase; Vascular Diseases

Inhibition of leukocyte adhesion to the vascular endothelium represents a novel and important approach for decreasing sickle cell disease (SCD) vaso-occlusion. Using a humanized SCD-mouse-model of tumor necrosis factor-α-induced acute vaso-occlusion, we herein present data demonstrating that short-term administration of either hydroxyurea or the phosphodiesterase 9 (PDE9) inhibitor, BAY73-6691, significantly altered leukocyte recruitment to the microvasculature. Notably, the administration of both agents led to marked improvements in leukocyte rolling and adhesion and decreased heterotypic red blood cell-leukocyte interactions, coupled with prolonged animal survival. Mechanistically, these rheologic benefits were associated with decreased endothelial adhesion molecule expression, as well as diminished leukocyte Mac-1-integrin activation and cyclic guanosine monophosphate (cGMP)-signaling, leading to reduced leukocyte recruitment. Our findings indicate that hydroxyurea has immediate beneficial effects on the microvasculature in acute sickle-cell crises that are independent of the drug's fetal hemoglobin-elevating properties and probably involve the formation of intravascular nitric oxide. In addition, inhibition of PDE9, an enzyme highly expressed in hematopoietic cells, amplified the cGMP-elevating effects of hydroxyurea and may represent a promising and more tissue-specific adjuvant therapy for this disease.

Topics: 3',5'-Cyclic-AMP Phosphodiesterases; Acute Disease; Anemia, Sickle Cell; Animals; Antisickling Agents; Cell Adhesion; Cell Communication; Cyclic GMP; Disease Models, Animal; Endothelium, Vascular; Erythrocytes; Female; Humans; Hydroxyurea; Leukocyte Rolling; Leukocytes; Male; Mice; Mice, Inbred C57BL; Pyrazoles; Pyrimidines; Tumor Necrosis Factor-alpha; Vascular Diseases

In this issue of Blood, Almeida et al report immediate benefits of hydroxyurea (HU) acute administration in diminishing vaso-occlusive processes in sickle cell disease (SCD) mice.(1)

Topics: Anemia, Sickle Cell; Animals; Antisickling Agents; Cyclic GMP; Female; Humans; Hydroxyurea; Male; Pyrazoles; Pyrimidines; Vascular Diseases

Endothelial dysfunction is a feature of hypertension and diabetes. Methylglyoxal (MG) is a reactive dicarbonyl metabolite of glucose and its levels are elevated in spontaneously hypertensive rats and in diabetic patients. We investigated if MG induces endothelial dysfunction and whether MG scavengers can prevent endothelial dysfunction induced by MG and high glucose concentrations.. Endothelium-dependent relaxation was studied in aortic rings from Sprague-Dawley rats. We also used cultured rat aortic and human umbilical vein endothelial cells. The MG was measured by HPLC and Western blotting and assay kits were used.. Incubation of aortic rings with MG (30 µM) or high glucose (25 mM) attenuated endothelium-dependent, acetylcholine-induced relaxation, which was restored by two different MG scavengers, aminoguanidine (100 µM) and N-acetyl cysteine (NAC) (600 µM). Treatment of cultured endothelial cells with MG or high glucose increased cellular MG levels, effects prevented by aminoguanidine and NAC. In cultured endothelial cells, MG and high glucose reduced basal and bradykinin-stimulated nitric oxide (NO) production, cGMP levels, and serine-1177 phosphorylation and activity of endothelial NO synthase (eNOS), without affecting threonine-495 and Akt phosphorylation or total eNOS protein. These effects of MG and high glucose were attenuated by aminoguanidine or NAC.. Our results show for the first time that MG reduced serine-1177 phosphorylation, activity of eNOS and NO production. MG caused endothelial dysfunction similar to that induced by high glucose. Specific and safe MG scavengers have potential to prevent endothelial dysfunction induced by MG and high glucose concentrations.

Topics: Acetylcholine; Acetylcysteine; Animals; Aorta; Cells, Cultured; Cyclic GMP; Endothelial Cells; Glucose; Guanidines; Humans; Male; Nitric Oxide; Nitric Oxide Synthase; Phosphorylation; Pyruvaldehyde; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Vascular Diseases; Vasodilation

This article summarizes perspectives on how reactive oxygen species (ROS) and redox signaling mechanisms participate in regulating vascular smooth muscle function that have resulted from our studies over the past 25 years in areas including oxygen sensing and the regulation of cGMP production by soluble guanylate cyclase (sGC) that were presented in the Robert M. Berne Distinguished Lectureship at the 2008 Experimental Biology Meeting. It considers mechanisms controlling the activity of sources of ROS including Nox oxidases and mitochondria by physiological stimuli, vascular diseases processes, and metabolic mechanisms linked to NAD(P)H redox and hypoxia. Metabolic interactions of individual ROS such as hydrogen peroxide with cellular peroxide metabolizing enzymes are viewed as some of the most sensitive ways of influencing cellular signaling systems. The control of cytosolic NADPH redox also seems to be a major contributor to bovine coronary arterial relaxation to hypoxia, where its oxidation functions to coordinate the lowering of intracellular calcium, whereas increased cytosolic NADPH generation in pulmonary arteries appears to maintain elevated Nox oxidase activity, and relaxation to hydrogen peroxide, which is attenuated by hypoxia. The sensitivity of sGC to nitric oxide seems to be regulated by thiol and heme redox systems controlled by cytosolic NADPH. Heme biosynthesis and metabolism are also important factors regulating the sGC system. The signaling pathways controlling oxidases and their colocalization with redox-regulated systems enables selective activation of numerous regulatory mechanisms influencing vascular function in physiological processes and the progression of aging-associated vascular diseases.

Topics: Aging; Animals; Calcium; Cyclic GMP; Guanylate Cyclase; Heme Oxygenase (Decyclizing); Humans; Hypoxia; Mitochondria, Muscle; Muscle, Smooth, Vascular; NADPH Oxidases; Nitric Oxide; Oxidation-Reduction; Reactive Oxygen Species; Signal Transduction; Vascular Diseases; Vasoconstriction; Vasodilation

Reduced bioavailability of nitric oxide (NO) is a hallmark of diabetes mellitus-induced vascular complications. In the present study we investigated whether a pharmacological increase of endothelial NO synthase (eNOS) production can restore the impaired hindlimb flow in a rat model of severe diabetes.. A model of diabetes mellitus was induced in male Sprague-Dawley rats by a single injection of streptozotozin. Rats were treated chronically with the eNOS transcription enhancer AVE3085 (10 mg [kg body weight](-1) day(-1); p.o.) or vehicle for 48 days and compared with controls. Endothelial function and arterial BP were investigated in vivo using an autoperfused hindlimb model and TIP-catheter measurement, respectively. Protein production of eNOS, total and phosphorylated vasodilator-stimulated phosphoprotein (VASP) were assessed in their quadriceps muscle tissue, whereas cyclic GMP (cGMP) concentrations were assessed in blood plasma. RNA levels of intracellular and vascular cell adhesion molecules (ICAM-1 and VCAM-1) were measured by real-time PCR.. Untreated diabetic rats showed significantly reduced quadriceps muscle contents of eNOS (-64%) and phosphorylated VASP (-26%) protein associated with impaired vascular function (maximum vasodilatation: -30%, p < 0.05) and enhanced production of ICAM-1 (+121%) and VCAM-1 (+156%). Chronic treatment with AVE3085 did not alter arterial BP or severe hyperglycaemia, but did lead to significantly increased production of eNOS (+95%), cGMP (+128%) and VASP phosphorylation (+65%) as well as to improved vascular function (+36%) associated with reduced production of ICAM-1 (-36%) and VCAM-1 (-58%).. In a rat model of severe diabetes, pharmacological enhancement of impaired eNOS production and NO-cGMP signalling by AVE3085 restores altered hindlimb blood flow and prevents vascular inflammation.

Topics: Animals; Cell Adhesion Molecules; Cyclic GMP; Diabetes Complications; Diabetes Mellitus, Experimental; Gene Expression Regulation; Hindlimb; Humans; Inflammation; Intracellular Signaling Peptides and Proteins; Lipid Peroxidation; Male; Microfilament Proteins; Muscles; Nitric Oxide Synthase Type II; Nitric Oxide Synthase Type III; Phosphoproteins; Rats; Rats, Sprague-Dawley; Streptozocin; Vascular Cell Adhesion Molecule-1; Vascular Diseases

Vascular calcification often occurs with advancing age, atherosclerosis, and metabolic disorders such as diabetes mellitus and end-stage renal disease. Vascular calcification is associated with cardiovascular events and increased mortality. Nitric oxide (NO) is crucial for maintaining vascular function, but little is known about how NO affects vascular calcification. The aim of this study was to examine the effect of NO on vascular calcification.. In this study, we examined the inhibitory effects of NO on calcification of murine vascular smooth muscle cells (VSMCs) in vitro. We measured calcium concentration, alizarin red staining, and alkaline phosphatase activity to examine the effect of NO on calcification of VSMCs and differentiation of VSMCs into osteoblastic cells. We also determined gene expression and levels of phosphorylation of Smad2/3 by RT-PCR and western blotting. NO inhibited calcification of VSMCs and differentiation of VSMCs into osteoblastic cells. An inhibitor of cyclic guanosine monophosphate (cGMP)-dependent protein kinase restored the inhibition by NO of osteoblastic differentiation and calcification of VSMCs. NO inhibited transforming growth factor-beta (TGF-beta)-induced phosphorylation of Smad2/3 and expression of TGF-beta-induced genes such as plasminogen activator inhibitor-1. In addition, NO inhibited expression of the TGF-beta receptor ALK5.. Our data show that NO prevents differentiation of VSMCs into osteoblastic cells by inhibiting TGF-beta signalling through a cGMP-dependent pathway. Our findings suggest that NO may play a beneficial role in atherogenesis in part by limiting vascular calcification.

Topics: Animals; Calcinosis; Cell Differentiation; Cells, Cultured; Cyclic GMP; Cyclic GMP-Dependent Protein Kinases; Mice; Mice, Inbred C57BL; Muscle, Smooth, Vascular; Nitric Oxide; Osteoblasts; Signal Transduction; Transforming Growth Factor beta; Vascular Diseases

Acrolein, an environmental pollutant and a lipid peroxidation product, is implicated in vascular pathogenesis. Although evidence indicates a link between vascular pathogenesis and acrolein, no direct studies relating to effects of acrolein on vascular function and responses are known. This study investigated the effects of acrolein on vascular function to understand the underlying mechanism of acrolein-induced vascular responses. Male Sprague-Dawley rats were treated with acrolein (2 or 4 mg/kg; i.p.) for 3 or 7 days. Urine and blood samples were collected. Changes in systolic blood pressure (SBP) and responses to acetylcholine and phenylephrine were determined. Acrolein (4 mg/kg, 7 days) significantly increased SBP by 25%, phenylephrine vasoconstriction by 2-fold, but decreased urinary excretion of nitrite by 25%. Acrolein inhibited generation of cyclic guanosine 3'5'-monophosphate (cGMP) by 98%, and did not alter expression of nitric oxide synthase (eNOS). Acrolein increased the generation of lipid hydroperoxide in plasma and aortic tissue by 21% and 124% respectively, increased glutathione-S-transferase (GST) and glutathione peroxidase (GSH-Px) activities. Acrolein up-regulated the expression of GST by 2 fold. These data suggest that induced SBP and altered vasoconstriction/vasodilatation in acrolein treated rats may be due to reduced availability of NO via increased free radical generation and reduced antioxidant defense.

Topics: Acrolein; Animals; Aorta, Thoracic; Blotting, Western; Cyclic GMP; Environmental Pollutants; Glutathione Peroxidase; Glutathione Transferase; Hemodynamics; Lipid Peroxidation; Male; Muscle, Smooth, Vascular; Nitric Oxide; Nitric Oxide Synthase; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Vascular Diseases; Vasoconstriction; Vasodilation

Patients with kidney failure present endothelial dysfunction, which was shown to be partly corrected by hemodialysis. No data exist on the effects of hemodialysis on endothelial dysfunction in kidney failure patients with associated vascular risk factors. The aim of this study was to evaluate the acute effects of hemodialysis on endothelial dysfunction in patients with kidney failure and associated vascular risk factors and to assess the role of endothelium-toxic substances.. We assessed endothelial dysfunction in 13 patients with chronic renal failure and other vascular risk factors before and after hemodialysis and in 13 healthy controls and simultaneously measured nitric oxide (NO) synthesis and activity. Endothelial dysfunction was studied using an echographic method as flow-mediated dilation (FMD) of the brachial artery; plasma NO2- and NO3-, cyclic guanosine-5-monophosphate (cGMP), plasma homocysteine levels and low molecular mass-advanced glycation end-products (LMM-AGEs) were simultaneously measured.. As compared with healthy controls, patients with renal failure showed a reduced FMD (2.89 +/- 1.43 vs. 7.81 +/- 1.54%, p < 0.01) which was not corrected by dialysis (after dialysis 2.40 +/- 1.65%, p = NS vs. pre). Plasma NO2- and NO3- were normal or slightly increased and remained unchanged after dialysis. Plasma cGMP levels were reduced and remained unchanged after dialysis. Homocysteine and LMM-AGE plasma levels were raised and, although significantly reduced by dialysis, remained higher than in controls.. Patients with kidney failure and associated vascular risk factors show an endothelial dysfunction related to defective NO activity, which is not corrected by hemodialysis despite the reduction, though not to normal, in homocysteine and LMM-AGE levels. Endothelial dysfunction may contribute to the progression of atherosclerosis in patients with kidney failure and vascular risk factors.

Topics: Adult; Aged; Biomarkers; Blood Pressure; Cyclic GMP; Diastole; Endothelium, Vascular; Female; Homocysteine; Humans; Kidney; Kidney Failure, Chronic; Male; Middle Aged; Nitrates; Nitrites; Regional Blood Flow; Renal Circulation; Renal Dialysis; Risk Factors; Statistics as Topic; Systole; Time Factors; Treatment Outcome; Vascular Diseases; Vasodilation

Plasma endothelin-1, the nitric oxide (NO) mediator intraplatelet cyclic guanosine monophosphate (cGMP), the prostacyclin mediator cyclic adenosine monophosphate (cAMP) and the macrophage derived inflammatory mediator plasma neopterin were measured in men with Type 2 diabetes mellitus (n=91), impaired glucose tolerance (IGT; n=51), previously abnormal glucose tolerance (PAGT; n=20), and 34 healthy control men. Plasma endothelin-1was higher in men with Type 2 diabetes mellitus than in controls [4.1 (1.0-14.3) vs. 2.1 (0.2-8. 7) ng/l; P<0.001). Intraplatelet cGMP was higher in men with PAGT [0. 84 (0.57-2.76) pmol/10(9) platelets; P<0.05], IGT [0.85 (0.48-3.53); P<0.001] and Type 2 diabetes mellitus [0.90 (0.47-3.86); P<0.001] than in controls [0.70 (0.42-1.70]. No differences existed between groups concerning intraplatelet cAMP or plasma neopterin. Plasma endothelin-1 correlated with fasting plasma glucose (r=0.33; P<0.001) and HbA1(c) (r=0.29; P<0.001). In conclusion, elevated plasma endothelin-1 in Type 2 diabetes mellitus and its relationship to glucose and HbA1(c) suggest a putative role for endothelin-1 in diabetic endothelial cell damage. Increased cGMP indicating enhanced production/activity of NO suggests that factors other than reduced NO activity contribute to enhanced platelet aggregation in diabetes.

Topics: Aged; Blood Glucose; Blood Platelets; Blood Pressure; Cholesterol; Cyclic GMP; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Endothelin-1; Glucose Intolerance; Glycated Hemoglobin; Humans; Leukocyte Count; Lipoproteins, HDL; Lipoproteins, LDL; Male; Middle Aged; Reference Values; Smoking; Vascular Diseases

Topics: Adolescent; Adult; Cerebrovascular Disorders; Coronary Disease; Cyclic AMP; Cyclic GMP; Female; Humans; Hypertension; Male; Middle Aged; Vascular Diseases

The literature concerned with studies of the occurrence and function of the cyclic nucleotides in blood vessels is reviewed. Emphasis is placed on the critical evaluation of the evidence which relates to the hypothesis that cyclic nucleotides meditate the effects of drugs and neurotransmitters on vascular contractility. The hypothesis that cyclic AMP mediates vasodilation, especially that induced by beta-adrenergic relaxation, is supported by many experimental approaches, but it is concluded that the evidence remains unconvincing based on the criteria established for such a mediator role. Possible sites of action of cyclic AMP are discussed. The demonstrated action of cyclic AMP on vascular membrane electrophysiology and calcium ion pumps are reviewed as possible causes of relaxation. The role of both nucleotides in vascular disease, especially hypertension is discussed. Finally the needs for further research in this area are suggested.

Topics: Animals; Arteries; Blood Vessels; Cattle; Cyclic AMP; Cyclic GMP; Dogs; Humans; Muscle Contraction; Muscle, Smooth; Phosphoric Diester Hydrolases; Rabbits; Rats; Swine; Sympatholytics; Sympathomimetics; Vascular Diseases; Vascular Resistance; Veins