cyclic-gmp and Atherosclerosis

To provide a systematic review of epidemiological data regarding the association between erectile dysfunction (ED) and lower urinary tract symptoms (LUTS) in men.. A research has been conducted on the Medline database using the keywords: ("erectile dysfunction" or "sexual dysfunction") and ("benign prostatic hyperplasia" or "lower urinary tract symptoms"). The eligibility of studies was defined using the PICOS method in accordance with the PRISMA statement. Cross-sectional studies and prospective cohorts assessing the association between LUTS and ED in the primary care setting or in general practice (i.e. exclusion of patients seen in outpatient urology or andrology) were included.. Among 898 reports assessed, seven studies were included in this systematic review (whole cohort: 1,196,393 men). There were five cross-sectional studies and two prospective cohorts. The whole seven studies reported an association between LUTS and ED (range of odds-ratio: 1.52-4.03). Four common pathogenic mechanisms were found in the literature, all of them being somewhat related with metabolic syndrome and cardiovascular risk factors: reduced nitric oxide (NO) pathway signalling, increased RhoA-Rho kinase signalling, autonomic nervous system hyperactivity and pelvic atherosclerosis.. The main limitations of this review were: a possible publication bias, the relatively low number of included studies and the lack of assessment of potential confounders such as factors related to sexual partner.. The close epidemiological and pathogenic links between LUTS and ED have given rise to a new nosological entity: the erectile urogenital dysfunction, which should be assessed globally with special considerations to frequently associated comorbidities such as metabolic syndrome and cardiovascular risk factors.

Topics: Atherosclerosis; Autonomic Nervous System; Cardiovascular Diseases; Comorbidity; Cross-Sectional Studies; Cyclic GMP; Endothelium, Vascular; Erectile Dysfunction; Humans; Impotence, Vasculogenic; Lower Urinary Tract Symptoms; Male; Metabolic Syndrome; Muscle, Smooth; Nitric Acid; Prospective Studies; Prostatic Hyperplasia; rho-Associated Kinases; rhoA GTP-Binding Protein; Risk Factors; Signal Transduction

Nitric oxide signaling, through eNOS (or possibly nNOS), and gap junction communication are essential for normal vascular function. While each component controls specific aspects of vascular function, there is substantial evidence for cross-talk between nitric oxide signaling and the gap junction proteins (connexins), and more recently, protein-protein association between eNOS and connexins. This review will examine the evidence for interaction between these pathways in normal and diseased arteries, highlight the questions that remain about the mechanisms of their interaction, and explore the possible interaction between nitric oxide signaling and the newly discovered pannexin channels. This article is part of a Special Issue entitled: The Communicating junctions, composition, structure and characteristics.

Topics: Animals; Atherosclerosis; Caveolin 1; Cells, Cultured; Connexins; Cyclic GMP; Diabetes Mellitus; Gap Junctions; Human Umbilical Vein Endothelial Cells; Humans; Hypertension; Mice; Models, Biological; Nerve Tissue Proteins; Nitric Oxide; Nitric Oxide Synthase Type III; Protein Binding; Signal Transduction

Although an abundant amount of research has been devoted to the study of angiogenesis, its precise mechanisms are incompletely understood. Numerous clinical trials focused on therapeutic angiogenesis for the treatment of tissue ischaemia have not been as successful as those of preclinical studies. Thus, additional studies are needed to better understand critical molecular mechanisms regulating ischaemic neovascularization to identify novel therapeutic agents. Nitric oxide (NO) plays a central role in ischaemic neovascularization through the generation of cyclic guanosine monophosphate (cGMP) and the activation of several other signalling responses. Accumulated evidence suggests that endothelial protein kinase A/endothelial NO synthase (PKA/eNOS) signalling may play an important role in ischaemic disorders by promoting neovascularization. This review highlights recent advances in the role of the PKA/eNOS and NO-cGMP-kinase cascade pathway in ischaemic neovascularization. We also discuss molecular relationships of PKA/eNOS with other angiogenic pathways and explore the possibility of activation of the NO/nitrite endocrine system as potential therapeutic targets for ischaemic angiogenesis.

Topics: Animals; Atherosclerosis; Cyclic AMP-Dependent Protein Kinases; Cyclic GMP; Humans; Ischemia; Neovascularization, Physiologic; Nitric Oxide; Nitric Oxide Synthase Type III; Reactive Oxygen Species; Signal Transduction

Benign prostatic hyperplasia (BPH) is a common disease in older men that can lead to lower urinary tract symptoms (LUTS). Male sexual dysfunction is also an age-related condition. Epidemiological studies have confirmed an association between BPH/LUTS and sexual dysfunction in ageing men that is independent of the effects of age, other co-morbidities and lifestyle factors. Proposed pathophysiological mechanisms for BPH/LUTS-associated sexual dysfunction include the nitric oxide/cyclic guanosine monophosphate (NO/cGMP) pathway, rho-kinase and endothelin-1 activity, autonomic nervous system overactivity and the metabolic syndrome, and pelvic organ atherosclerosis. Both BPH/LUTS and sexual dysfunction can have a substantial negative impact on a man's quality of life. However, urologists and primary care physicians appear to under-recognise sexual dysfunction in men with BPH/LUTS. Current guidelines recommend alpha-blockers and 5-alpha reductase inhibitors, either alone or in combination, among appropriate medical treatment options for BPH/LUTS. Randomised, controlled trials demonstrate that these therapies can be associated with sexual adverse effects (AEs) such as loss of libido, erectile dysfunction and ejaculatory disorders. Sexual dysfunction should be fully evaluated in men requiring treatment for BPH/LUTS using validated questionnaires. Management of sexual dysfunction in men treated for BPH/LUTS should involve assessment of co-morbidities and concomitant medications, consideration of lifestyle interventions such as weight loss and increased physical activity to improve risk factors and, if necessary, introduction of pharmacotherapies. In addition, physicians should provide patients with proper counselling on the possible sexual AEs of medical therapies for BPH/LUTS and their impact on sexual satisfaction, while being aware of the possibility that counselling in itself is likely to influence reported rates of sexual dysfunction.

Topics: 5-alpha Reductase Inhibitors; Adrenergic alpha-Antagonists; Adult; Aged; Atherosclerosis; Autonomic Nervous System Diseases; Cyclic GMP; Drug Combinations; Endothelin-1; Humans; Male; Metabolic Syndrome; Middle Aged; Nitric Oxide; Prostatic Hyperplasia; Prostatism; rho-Associated Kinases; Sexual Dysfunction, Physiological

This review focuses on the relationship among sexual dysfunction (SD), lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH), and related therapies.. We reviewed the current literature to provide an overview of current data regarding epidemiology and pathophysiology of SD and LUTS. Moreover, we analysed the impact of currently available therapies of LUTS/BPH on both erectile dysfunction (ED) and ejaculatory dysfunction and the effect of phosphodiesterase type 5 inhibitors (PDE5-Is) in patients with ED and LUTS.. We conducted a Medline search to identify original articles, reviews, editorials, and international scientific congress abstracts by combining the following terms: benign prostatic hyperplasia, lower urinary tract symptoms, sexual dysfunction, erectile dysfunction, and ejaculatory dysfunction.. We conducted a comprehensive analysis of more relevant general population-based and BPH/LUTS or SD clinic-based trials and evaluated the common pathophysiologic mechanisms related to both conditions. In a further step, the overall impact of current BPH/LUTS therapies on sexual life, including phytotherapies, novel drugs, and surgical procedures, was scrutinized. Finally, the usefulness of PDE5-Is in LUTS/BPH was critically analysed, including preclinical and clinical research data as well as possible mechanisms of action that may contribute to the efficacy of PDE5-Is with LUTS/BPH.. Community-based and clinical data demonstrate a strong and consistent association between LUTS and ED, suggesting that elderly men with LUTS should be evaluated for SD and vice versa. Pathophysiologic hypotheses regarding common basics of LUTS and SD as discussed in the literature are (1) alteration of the nitric oxide (NO)-cyclic guanosine monophosphate (cGMP) pathway, (2) enhancement of RhoA-Rho-kinase (ROCK) contractile signalling, (3) autonomic adrenergic hyperactivity, and (4) pelvic atherosclerosis. The most important sexual adverse effects of medical therapies are ejaculation disorders after the use of some α-blockers and sexual desire impairment, ED, and ejaculatory disorders after the use of α-reductase inhibitors. Minimally invasive, conventional, and innovative surgical treatments for BPH may induce both retrograde ejaculation and ED. PDE5-Is have demonstrated significant improvements in both LUTS and ED in men with BPH; combination therapy with PDE5-Is and α1-adrenergic blockers seems superior to PDE5-I monotherapy.

Topics: Adrenergic alpha-1 Receptor Antagonists; Atherosclerosis; Clinical Trials as Topic; Cyclic GMP; Drug Therapy, Combination; Humans; Lower Urinary Tract Symptoms; Male; Meta-Analysis as Topic; Nitric Oxide; Phosphodiesterase 5 Inhibitors; Prevalence; Prostatic Hyperplasia; rho-Associated Kinases; Sexual Dysfunction, Physiological

Endothelial dysfunction associated with decreased nitric oxide (NO) bioactivity is a major feature of vascular diseases such as atherosclerosis or diabetes. Sodium nitroprusside (SNP)-induced relaxation is entirely dependent on cyclic guanosine monophosphate (cGMP) and preserved in atherosclerosis, suggesting that smooth muscle response to NO donor is intact. However, NO gas activates both cGMP-dependent and -independent signal pathways in vascular smooth muscle cells, and oxidative stress associated with vascular diseases selectively impairs cGMP-independent relaxation to NO. Sarco/endoplasmic reticulum Ca(2+) ATPase (SERCA), which regulates intracellular Ca(2+) levels by pumping Ca(2+) into store, is a major cGMP-independent target for NO. Physiological levels of reactive nitrogen species (RNS) S-glutathiolate SERCA at Cys674 to increase its activity, and the augmentation of RNS in vascular diseases irreversibly oxidizes Cys674 or nitrates tyrosine residues at Tyr296-Tyr297, which are associated with loss of function. S-glutathiolation of various proteins by NO can explain redox-sensitive cGMP-independent actions, and oxidative inactivation of target proteins for NO can be associated with the pathogenesis of cardiovascular diseases. Oxidative inactivation of SERCA is also implicated with dysregulation of smooth muscle migration, promotion of platelet aggregation, and impairment of cardiac function, which can be implicated with restenosis, pathological angiogenesis, thrombosis, as well as heart failure. Analysis of posttranslational oxidative modifications of SERCA and the preservation of SERCA function can be novel strategies against cardiovascular diseases associated with oxidative stress.

Topics: Animals; Antioxidants; Atherosclerosis; Cyclic GMP; Cyclic GMP-Dependent Protein Kinases; Diabetic Angiopathies; Endothelium, Vascular; Glutathione; Heart Failure; Humans; Mice; Models, Animal; Muscle, Smooth, Vascular; Nitric Oxide; Oxidative Stress; Protein Processing, Post-Translational; Rabbits; Rats; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Tyrosine; Vasodilation

To review the current literature regarding the relationship between lower urinary tract symptoms (LUTS) and erectile dysfunction (ED), and the role of phosphodiesterase-5 (PDE5) inhibitors for the treatment of LUTS. Review of recently published (1990-2009) data regarding epidemiologic and pathophysiologic mechanisms are involved in LUTS-ED, focusing on PDE5 inhibitors particularly evidenced from level 1 clinical trials. Search terms included phosphodiesterase inhibitors, nitric oxide, autonomic hyperactivity, Rho-kinase, atherosclerosis, LUTS, benign prostatic hypertrophy, and ED. Results of several epidemiologic studies show a possible causal relationship between LUTS and ED. Four possible mechanisms have been proposed to explain this association. Multiple large clinical trials have shown a benefit in LUTS after PDE5-inhibitors treatment. PDE5 inhibitors show promise as a future treatment for LUTS, either in conjunction with existing therapies or as a primary treatment.

Topics: Aged; Aging; Animals; Atherosclerosis; Autonomic Nervous System; Clinical Trials as Topic; Cyclic GMP; Cyclic Nucleotide Phosphodiesterases, Type 5; Erectile Dysfunction; Humans; Male; Middle Aged; Nitric Oxide; Nitric Oxide Synthase; Phosphodiesterase Inhibitors; Prostate; Prostatic Hyperplasia; Prostatism; rho-Associated Kinases

Nitric oxide (NO) produced by endothelial NO synthase (NOS) in low concentrations is a unique messenger molecule with key homeostatic functions concerning the prevention of pathological vascular and tissue changes such as increases in blood pressure, platelet degranulation, mononuclear cell infiltration, cell proliferation and extracellular matrix protein accumulation. This is in contrast to high levels of NO derived from inducible NOS which act as detrimental effector molecules and free radicals in immune response. Deficiency in NO's protective signaling actions is a major characteristic in numerous experimental and human disease situations. The main function of the NO signaling pathway is activation of the soluble guanylate cyclase (sGC) enzyme with subsequent generation of cyclic guanosine monophosphate (cGMP) as a second messenger and downstream mediator. In the past, attempts to overcome deficiency in endothelial NO effects were focused primarily on increasing the supply with the NO precursor L-arginine or on the use of directly NO-releasing compounds. The clinical impact of these strategies, however, was rather limited. Recent state-of-the-art studies have revealed that NO signaling is highly regulated at the transcriptional level and that deficiency in NO signaling correlates closely with pathological changes. In parallel efforts, novel pharmacological compounds which specifically enhance NO/cGMP signaling have been developed and have demonstrated remarkable efficacy in experimental disease settings. In this review, we summarize the current state of knowledge on the impairment of NO/cGMP signaling and about its pharmacological stimulation. In the first part, experimental renal fibrosis, i.e. the tandem rat model of acute anti-thy1 glomerulonephritis and progressive anti-thy1 renal fibrosis will serve as a paradigm for introducing this new and exciting field. In the second part, we will address the most recent findings on NO signaling in non-renal diseases. Together, these results point out that deficiency in NO/cGMP is a common key pathway as well as a novel therapeutic target in a number of diseases.

Topics: Animals; Atherosclerosis; Cyclic GMP; Fibrosis; Glomerulonephritis; Heart Failure; Humans; Hypertension, Pulmonary; Kidney; Kidney Diseases; Liver Cirrhosis; Nitric Oxide; Nitric Oxide Synthase Type III; Signal Transduction; Thrombosis

Soluble guanylyl cyclase (sGC) is one of the key enzymes of the nitric-oxide (NO)/cyclic 3',5'-guanosine monophosphate (cGMP) pathway. Located in virtually all mammalian cells, it controls the vessel tone, smooth muscle cell growth, platelet aggregation, and leukocyte adhesion. In vivo sGC activity is mainly regulated by NO which in turn is released from L-arginine by nitric oxide synthases. One of the main diseases of the cardiovascular system, endothelial dysfunction, leads to a diminished NO synthesis and thus increases vessel tone as well as the risk of thrombosis. The predominant therapeutic approach to this condition is a NO replacement therapy, as exemplified by organic nitrates, molsidomin, and other NO releasing substances. Recent advances in drug discovery provided a variety of other approaches to activate sGC, which may help to circumvent both the tolerance problem and some non-specific actions associated with NO donor drugs. Substances like BAY 41-2272 stimulate sGC in a heme-dependent fashion and synergize with NO, allowing to enhance the effects both of endogenous NO and of exogenous NO donors. On the other hand, heme-independent activators like BAY 58-2667 allow to activate sGC even if it is rendered unresponsive to NO due to oxidative stress or heme loss. Furthermore, a few substances have been described as specific inhibitors of sGC that allow to alleviate the effects of excess NO production as seen in shock. This review discusses the cardiovascular effects of heme-dependent and heme-independent activators as well as of inhibitors of sGC.

Topics: Animals; Atherosclerosis; Carbon Monoxide; Cardiovascular Agents; Cyclic GMP; Guanylate Cyclase; Humans; Hypertension; Hypertension, Pulmonary; Nitric Oxide; Nitric Oxide Donors; Signal Transduction

Nitric oxide regulation of the cardiovascular system involves both cGMP-dependent and independent mechanisms. The former directly interacts with the family of catabolic phosphodiesterases (PDEs) that control cGMP levels and thus distal effects such as protein kinase G stimulation. Growing evidence supports an important role of several PDEs, including PDE1, PDE2, and PDE5, in the regulation of cGMP in both vascular smooth muscle and cardiac myocytes. These PDEs have relatively little impact on resting function, but they can potently modulate acute contractile tone in cells stimulated by external agonists such as angiotensin or catecholamines. Regulation by PDEs is compartmentalized, with selective interactions occurring between a given source of cGMP and PDE hydrolysis. PDE1 and/or PDE5 are also reportedly up-regulated in chronic disease conditions such as atherosclerosis or cardiac pressure-load stress and heart failure as well as in response to long-term exposure to nitrates. Such up-regulation is thought to contribute to vascular and cardiac pathophysiology and to drug tolerance. Recent studies utilizing selective PDE5 inhibitors support significant cross-signaling with NO-cGMP synthetic pathways that may be particularly helpful in treating certain disease states.

Topics: Animals; Atherosclerosis; Cyclic GMP; Humans; Muscle, Smooth, Vascular; Nitric Oxide; Phosphoric Diester Hydrolases; Up-Regulation

Several clinical and population-based studies suggest that dehydroepiandrosterone (DHEA) and its sulphate (DHEA-S) play a protective role against atherosclerosis and coronary artery disease in human. However, the mechanisms underlying this action are still unknown. It has recently been suggested that DHEA-S could delay atheroma formation through an increase in nitric oxide (NO) production.. Twenty-four aged male subjects [age (mean +/- SEM): 65.4 +/- 0.7 year; range: 58.2-67.6 years] underwent a blinded placebo controlled study receiving DHEA (50 mg p.o. daily at bedtime) or placebo for 2 months. Platelet cyclic guanosine-monophosphate (cGMP) concentration (as marker of NO production) and serum levels of DHEA-S, DHEA, IGF-I, insulin, glucose, oestradiol (E(2)), testosterone, plasminogen activator inhibitor (PAI)-1 antigen (PAI-1 Ag), homocysteine and lipid profile were evaluated before and after the 2-month treatment with DHEA or placebo.. At the baseline, all variables in the two groups were overlapping. All parameters were unchanged after treatment with placebo. Conversely, treatment with DHEA (a) increased (P < 0.001 vs. baseline) platelet cGMP (111.9 +/- 7.1 vs. 50.1 +/- 4.1 fmol/10(6) plts), DHEA-S (13.6 +/- 0.8 vs. 3.0 +/- 0.3 micromol/l), DHEA (23.6 +/- 1.7 vs. 15.3 +/- 1.4 nmol/l), testosterone (23.6 +/- 1.0 vs. 17.7 +/- 1.0 nmol/l) and E(2) (72.0 +/- 5.0 vs. 60.0 +/- 4.0 pmol/l); and (b) decreased (P < 0.05 vs. baseline) PAI-1 Ag (27.4 +/- 3.8 vs. 21.5 +/- 2.5 ng/ml) and low-density lipoprotein (LDL) cholesterol (3.4 +/- 0.2 vs. 3.0 +/- 0.2 mmol/l). IGF-I, insulin, glucose, triglycerides, total cholesterol, HDL cholesterol, HDL2 cholesterol, HDL3 cholesterol, apolipoprotein A1 (ApoA1), apolipoprotein B (ApoB) and homocysteine levels were not modified by DHEA treatment.. This study shows that short-term treatment with DHEA increased platelet cGMP production, a marker of NO production, in healthy elderly subjects. This effect is coupled with a decrease in PAI-1 and LDL cholesterol levels as well as an increase in testosterone and E(2) levels. These findings, therefore, suggest that chronic DHEA supplementation would exert antiatherogenic effects, particularly in elderly subjects who display low circulating levels of this hormone.

Topics: Aged; Atherosclerosis; Biomarkers; Blood Chemical Analysis; Blood Platelets; Cyclic GMP; Dehydroepiandrosterone; Dehydroepiandrosterone Sulfate; Drug Administration Schedule; Humans; Male; Middle Aged; Nitric Oxide; Vasodilator Agents

This study aimed to investigate how atherosclerosis affects the soluble guanylate cyclase (sGC) system in coronary arteries. Rabbits were fed a normal diet for 12 weeks (N group) or a diet containing high cholesterol (1%) for 4 weeks (S-HC group) and 12 weeks (L-HC group). Cholesterol deposition in the intima of coronary arteries was observed in the S-HC group, but the formation of an atherosclerotic plaque was not observed. In contrast, a major plaque developed in the L-HC group. The relaxant response of isolated coronary arteries to sodium nitroprusside (SNP, nitric oxide donor) was not different between the N and S-HC groups, whereas the response in the L-HC group was markedly attenuated. The relaxation induced by BAY 60-2770 (sGC activator) tended to be augmented in the S-HC group, but it was significantly impaired in the L-HC group compared to that in the N group. sGC β1 immunostaining was equally detected in the medial layer of the arteries among the N, S-HC, and L-HC groups. In addition, a strong staining was observed in the plaque region of the L-HC group. cGMP levels in the arteries stimulated with SNP were identical in the N and S-HC groups and slightly lower in the L-HC group than the other groups. BAY 60-2770-stimulated cGMP formation tended to be increased in the S-HC and L-HC groups. These findings suggest that the sGC system was not normal in atherosclerotic coronary arteries. The redox state of sGC and the distribution pattern are likely to change with the progression of atherosclerosis.

Topics: Animals; Atherosclerosis; Cholesterol, Dietary; Coronary Vessels; Cyclic GMP; Male; Rabbits; Soluble Guanylyl Cyclase

Background Cyclic guanosine monophosphate (cGMP) is a second messenger regulated through natriuretic peptide and nitric oxide pathways. Stimulation of cGMP signaling is a potential therapeutic strategy for heart failure with preserved ejection fraction (HFpEF) and atherosclerotic cardiovascular disease (ASCVD). We hypothesized that plasma cGMP levels would be associated with lower risk for incident HFpEF, any HF, ASCVD, and coronary heart disease (CHD). Methods and Results We conducted a case-cohort analysis nested in the ARIC (Atherosclerosis Risk in Communities) study. Plasma cGMP was measured in 875 participants at visit 4 (1996-1998), with oversampling of incident HFpEF cases. We used Cox proportional hazard models to assess associations of cGMP with incident HFpEF, HF, ASCVD (CHD+stroke), and CHD. The mean (SD) age was 62.4 (5.6) years and median (interquartile interval) cGMP was 3.4 pmol/mL (2.4-4.6). During a median follow-up of 9.9 years, there were 283 incident cases of HFpEF, 329 any HF, 151 ASCVD, and 125 CHD. In models adjusted for CVD risk factors, the hazard ratios (95% CI) associated with the highest cGMP tertile compared with lowest for HFpEF, HF, ASCVD, and CHD were 1.88 (1.17-3.02), 2.18 (1.18-4.06), 2.84 (1.44-5.60), and 2.43 (1.19-5.00), respectively. In models further adjusted for N-terminal-proB-type natriuretic peptide, associations were attenuated for HFpEF and HF but remained statistically significant for ASCVD (2.56 [1.26-5.20]) and CHD (2.25 [1.07-4.71]). Conclusions Contrary to our hypothesis, higher cGMP levels were associated with incident CVD in a community-based cohort. The associations of cGMP with HF or HFpEF may be explained by N-terminal-proB-type natriuretic peptide, but not for ASCVD and CHD.

Topics: Aged; Atherosclerosis; Biomarkers; Case-Control Studies; Coronary Disease; Cyclic GMP; Female; Heart Disease Risk Factors; Heart Failure; Humans; Incidence; Male; Middle Aged; Natriuretic Peptide, Brain; Peptide Fragments; Predictive Value of Tests; Prospective Studies; United States

Angiotensin (Ang)-(1-7) ameliorates vascular injury by increasing nitric oxide (NO) bioavailability. Evidence that Ang-(1-7) attenuates the development of atherosclerosis through a NO-dependent mechanism is still missing. Moreover, it has been postulated that Ang-(1-7) may mediate its effects by other mechanisms than Mas receptor activation. To investigate Ang-(1-7)-dependent Mas receptor function, we treated apoE-KO and apoE/Mas-KO mice chronically with Ang-(1-7) (82 μg/kg per hour) or saline for 6 weeks. Flow-mediated dilation (FMD), a measure for NO-dependent vasodilation and the most accepted prognostic marker for the development of atherosclerosis, was measured in vivo. Chronic Ang-(1-7) treatment improved FMD and attenuated the development of atherosclerosis in apolipoproteinE (apoE)-KO but not in apoE/Mas-KO mice. These effects were accompanied by increased aortic nitrite and cGMP levels. To test whether Ang-(1-7) modulates atherosclerosis through a NO-dependent mechanism, apoE-KO mice were treated with the NO synthase inhibitor L-NAME (20 mg/kg/day) in the presence or absence of Ang-(1-7). L-NAME treatment reduced aortic nitrite content and increased blood pressure and exaggerated atherosclerosis compared to untreated apoE-KO mice. In L-NAME-treated apoE-KO mice, chronic Ang-(1-7) treatment did not increase aortic nitrite content and consequently showed no effect on blood pressure and the development of atherosclerosis. The present study proves that Ang-(1-7) mediates its protective vascular effects through Mas receptor activation. Moreover, Ang-(1-7)-mediated NO generation is essential for improving vascular function and prevents atherosclerosis in apoE-KO mice.

Topics: Angiotensin I; Animals; Aorta; Apolipoproteins E; Atherosclerosis; Blood Pressure; Cyclic GMP; Male; Mice; Mice, Inbred C57BL; Mice, Knockout, ApoE; NG-Nitroarginine Methyl Ester; Nitric Oxide; Nitric Oxide Synthase; Peptide Fragments; Proto-Oncogene Mas; Proto-Oncogene Proteins; Receptors, G-Protein-Coupled; Vasodilation

Epidemiological studies have demonstrated that N-methylnicotinamide (MNA) may exert antithrombotic and anti-inflammatory effects on the endothelium. However, the exact role of MNA in endothelial function remains uncertain.. Apolipoprotein E-deficient (apoE(-/-) ) mice fed with a high-fat, high-cholesterol diet (HCD) and human umbilical vein endothelial cells (HUVECs) were used to explore the role of MNA in endothelial function and its underlying mechanism. The endothelium-dependent vasorelaxation to acetylcholine in the aortas of low and high dose MNA-fed apoE(-/-) mice was improved by 24 and 36% (p < 0.05), respectively, compared with high-fat, HCD-fed control. MNA significantly increased nitric oxide/cyclic guanosinemonophosphate levels and decreased asymmetric dimethylarginine (ADMA) concentrations by induction of dimethylarginine dimethylaminohydrolase (DDAH)2 both in aorta and endothelial cells. Neither the activity nor the protein expression of DDAH1 was influenced upon MNA treatment. Then, DDAH2 depletion by RNA interference in HUVECs abolished the protective effect of MNA on endothelial function. Mechanically, this could be attributed to a direct modulation of the methylation level of DDAH2 gene promoter region by MNA.. The present study reveals a novel mechanism through which MNA improves endothelial dysfunction and attenuates atherogenesis via the modulation of ADMA-DDAH axis.

Topics: Acetylcholine; Amidohydrolases; Animals; Aorta; Arginine; Atherosclerosis; Cholesterol, Dietary; Cyclic GMP; Diet, High-Fat; Endothelium, Vascular; Human Umbilical Vein Endothelial Cells; Humans; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Niacinamide; Nitric Oxide; Promoter Regions, Genetic; Vasodilation

Gal-geun-dang-gwi-tang (GGDGT), an herbal medicine, is used to treat hypertension, stroke, and other inflammatory disorders in the clinical setting. Recently, GGDGT was recognized by the Korea Institute of Oriental Medicine. This study aimed to evaluate the effects of GGDGT in a diabetic atherosclerosis model using apolipoprotein E knockout (ApoE-/-) mice fed a Western diet.. The mice were divided into four groups: control group, C57BL6J mice receiving a regular diet (RD); ApoE-/- group, ApoE-/- mice receiving a Western diet (WD); rosiglitazone group, ApoE-/- mice receiving rosiglitazone (WD + 10 mg · kg(-1) · day(-1)); GGDGT group, ApoE-/- mice receiving GGDGT (WD + 200 mg · kg(-1) · day(-1)).. Treatment with GGDGT significantly improved glucose tolerance and plasma lipid levels. In addition, GGDGT ameliorated acetylcholine-induced vascular relaxation of the aortic rings. Immunohistochemical staining showed that GGDGT suppressed intercellular adhesion molecule (ICAM)-1 expression; however, expression of endothelial nitric oxide synthase (eNOS) and insulin receptor substrate (IRS)-1 were restored in the thoracic aorta and skeletal muscle, respectively.. These findings suggest that GGDGT attenuates endothelial dysfunction via improvement of the nitric oxide (NO)-cyclic guanosine monophosphate (cGMP) signalling pathway and improves insulin sensitivity in diabetic atherosclerosis.

Topics: Animals; Aorta, Thoracic; Apolipoproteins E; Atherosclerosis; Blood Glucose; Cyclic GMP; Diabetic Angiopathies; Diet, Western; Endothelium, Vascular; Hypertension; Insulin; Insulin Receptor Substrate Proteins; Insulin Resistance; Lipids; Male; Medicine, Korean Traditional; Mice, Inbred C57BL; Mice, Knockout; Nitric Oxide; Nitric Oxide Synthase Type III; Phytotherapy; Plant Extracts; Vasodilation

Chronic supplementation with L-citrulline plus L-arginine has been shown to exhibit anti-atherosclerotic effects. However, the short-term action of this combination on the nitric oxide (NO)-cGMP pathway remains to be elucidated. The objective of the present study was to investigate the acute effects of a combination of oral L-citrulline and L-arginine on plasma L-arginine and NO levels, as well as on blood circulation.. Rats or New Zealand white rabbits were treated orally with L-citrulline, or L-arginine, or a combination of each at half dosage. Following supplementation, plasma levels of L-arginine, NOx, cGMP and changes in blood circulation were determined sequentially.. L-Citrulline plus L-arginine supplementation caused a more rapid increase in plasma L-arginine levels and marked enhancement of NO bioavailability, including plasma cGMP concentrations, than with dosage with the single amino acids. Blood flow in the central ear artery in rabbits was also significantly increased by L-citrulline plus L-arginine administration as compared with the control.. Our data show for the first time that a combination of oral L-citrulline and L-arginine effectively and rapidly augments NO-dependent responses at the acute stage. This approach may have clinical utility for the regulation of cardiovascular function in humans.

Topics: Administration, Oral; Animals; Arginine; Atherosclerosis; Biological Availability; Citrulline; Cyclic GMP; Dietary Supplements; Drug Synergism; Humans; Male; Nitric Oxide; Rabbits; Rats; Rats, Sprague-Dawley; Signal Transduction

Xuezhikang is the extract of red yeast rice, which has been widely used for the management of atherosclerotic disease, but the molecular basis of its antiatherosclerotic effects has not yet been fully identified. Here we investigated the changes of eNOS in vascular endothelia and RBCs, eNOS regulatory factor Caveolin-1 in endothelia, and hemorheological parameters in atherosclerotic rats to explore the protective effects of Xuezhikang.. Wistar rats were divided into 4 groups (n = 12/group) group C, controls; group M, high-cholesterol diet (HCD) induced atherosclerotic models; group X, HCD+Xuezhikang; and group L, HCD +Lovastatin. In group X, Xuezhikang inhibited oxidative stress, down-regulated caveolin-1 in aorta wall (P<0.05), up-regulated eNOS expression in vascular endothelia and erythrocytes (P<0.05), increased NOx (nitrite and nitrate) in plasma and cGMP in erythrocyte plasma and aorta wall (P<0.05), increased erythrocyte deformation index (EDI), and decreased whole blood viscosity and plasma viscosity (P<0.05), with the improvement of arterial pathology.. Xuezhikang up-regulated eNOS expression in vascular endothelia and RBCs, increased plasma NOx and improved abnormal hemorheology in high cholesterol diet induced atherosclerotic rats. The elevated eNOS/NO and improved hemorheology may be beneficial to atherosclerotic disease.

Topics: Animals; Antioxidants; Aorta; Atherosclerosis; Caveolin 1; Cell Membrane; Cyclic GMP; Drugs, Chinese Herbal; Erythrocytes; Hemorheology; Lipids; Malondialdehyde; Medicine, Chinese Traditional; Nitric Oxide; Nitric Oxide Synthase Type III; Oxidative Stress; Rats; Superoxide Dismutase

Hypercholesterolemia increases the incidence of atherosclerosis and its pathologic complications. This study was performed to test the effect of an ethanol extract of Cynanchum wilfordii (ECW) on vascular dysfunction in rats fed with high fat/cholesterol diets (HFCD). Male rats were fed a HFCD consisting of 7.5% cocoa butter and 1.25% cholesterol, with or without 100, 200 mg/day/kg ECW. Rats fed with HFCD increased body weight associated with an increase in plasma low-density lipoprotein (LDL) cholesterol level. Chronic ECW treatment in HFCD-fed rats lessened LDL cholesterol and triglyceride levels as well as elevated high-density lipoprotein (HDL) cholesterol. Chronic ECW treatment recovered the HFCD-induced increase in systolic blood pressure, maintained smooth and soft intima endothelial layers by the decrease of intima-media thickness. ECW significantly recovered the diet-induced decrease in vasorelaxation to acetylcholine, high-dose ECW apparently increased vasorelaxation response to sodium nitroprusside in rats fed with HFCD. ECW clearly restored the HFCD-induced reduction in endothelial nitric oxide (NO) synthase expression and Akt expression levels in aortic tissue, leading to improve endothelial function through an increase in endothelium-derived NO production. Furthermore, treatment of ECW significantly recovered the HFCD-induced decrease in aortic cGMP levels in rats. These findings suggest that ECW ameliorates hypertension and endothelial dysfunction via improvement of NO/cGMP signaling pathway in aortic tissue of rats fed with HFCD, suggesting a vascular protective role for this herb in the treatment and prevention of atherosclerotic vascular disease.

Topics: Animals; Aorta; Atherosclerosis; Cholesterol; Cholesterol, HDL; Cholesterol, LDL; Cyclic GMP; Cynanchum; Dietary Fats; Drug Synergism; Hypertension; Male; Nitric Oxide; Nitroprusside; Plant Extracts; Rats; Rats, Sprague-Dawley; Signal Transduction; Tunica Intima; Vasodilation; Vasodilator Agents

Atherosclerotic lesions develop in regions of disturbed flow, whereas laminar flow protects from atherogenesis; however, the mechanisms involved are not completely elucidated. Integrins are mechanosensors of shear stress in endothelial cells, and integrin-linked kinase (ILK) is important for blood vessel integrity and cardiovascular development.. To explore the role of ILK in vascular function by studying conditionally ILK-deficient (cKO) mice and human atherosclerotic arteries.. ILK expression was detected in the endothelial cell layer of nonatherosclerotic vessels but was absent from the endothelium of atherosclerotic arteries. Live ultrasound imaging revealed that acetylcholine-mediated vasodilatation was impaired in cKO mice. These mice exhibited lowered agonist-induced nitric oxide synthase (NOS) activity and decreased cyclic guanosine monophosphate and nitrite production. ILK deletion caused endothelial NOS (eNOS) uncoupling, reflected in reduced tetrahydrobiopterin (BH4) levels, increased BH2 levels, decreased dihydrofolate reductase expression, and increased eNOS-dependent generation of superoxide accompanied by extensive vascular protein nitration. ILK reexpression prevented eNOS uncoupling in cKO cells, whereas superoxide formation was unaffected by ILK depletion in eNOS-KO cells, indicating eNOS as a primary source of superoxide anion. eNOS and ILK coimmunoprecipitated in aortic lysates from control animals, and eNOS-ILK-shock protein 90 interaction was detected in human normal mammary arteries but was absent from human atherosclerotic carotid arteries. eNOS-ILK interaction in endothelial cells was prevented by geldanamycin, suggesting heat shock protein 90 as a binding partner.. Our results identify ILK as a regulatory partner of eNOS in vivo that prevents eNOS uncoupling, and suggest ILK as a therapeutic target for prevention of endothelial dysfunction related to shear stress-induced vascular diseases.

Topics: Aged; Aged, 80 and over; Animals; Arteries; Atherosclerosis; Cattle; Cells, Cultured; Cyclic GMP; Disease Models, Animal; Down-Regulation; Endothelium, Vascular; Female; HSP90 Heat-Shock Proteins; Humans; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Middle Aged; Nitric Oxide; Nitric Oxide Synthase Type III; Protein Serine-Threonine Kinases; Signal Transduction; Vasomotor System

Insulin/insulin-like growth factor (IGF-1) signaling is important for a variety of age-related processes. However, whether or not it affects atherosclerosis is unknown.. Six groups of 6 male New Zealand white rabbits were treated for 12 weeks under the following conditions: Groups YC and YIGF: Young rabbits (10 weeks old) were fed regular chow w/wo IGF-1(Somazon 0.1 mg/kg/day, s.c.). Groups HC and HIGF: young rabbits were fed HCD (0.5% cholesterol plus regular chow) w/wo IGF-1. Groups OC and OIGF: old rabbits (120 weeks old) were fed regular chow w/wo IGF-1.. Plasma lipid levels, endothelial responses and morphological findings did not differ between groups YIGF and YC. Animals in group HC had increased plasma lipid levels and atheromas. In group HIGF, IGF led to atheromas with increased plasma insulin growth factor binding protein 3 (IBP3), inducible nitric oxide synthase(iNOS) expression and nitrotyrosine staining, macrophage staining, SM1 staining and SM embryo staining compared to HC. Basal nitric oxide (NO) release evaluated by plasma NO metabolites (NOx) and cGMP levels were lowest in the HIGF group.. Overall, IGF-1 promoted atherosclerosis by affecting endothelial function and aging. These findings indicate that Insulin/IGF1 may contribute to atherogenesis in the elderly.

Topics: Acetylcholine; Aging; Animals; Aorta, Thoracic; Atherosclerosis; Cholesterol, Dietary; Cyclic GMP; Drug Therapy, Combination; Endothelium, Vascular; Hyperlipidemias; Injections, Subcutaneous; Insulin-Like Growth Factor Binding Protein 3; Insulin-Like Growth Factor I; Lipids; Male; Nitric Oxide; Nitric Oxide Synthase; Rabbits; Signal Transduction; Vasodilator Agents

ApolipoproteinE-deficient [apoE (-/-)] mice, a model of human atherosclerosis, develop endothelial dysfunction caused by decreased levels of nitric oxide (NO). The endogenous peptide, angiotensin-(1-7) [Ang-(1-7)], acting through its specific GPCR, the Mas receptor, has endothelium-dependent vasodilator properties. Here we have investigated if chronic treatment with Ang-(1-7) improved endothelial dysfunction in apoE (-/-) mice.. ApoE (-/-) mice fed on a lipid-rich Western diet were divided into three groups and treated via osmotic minipumps with either saline, Ang-(1-7) (82 µg·kg(-1) ·h(-1) ) or the same dose of Ang-(1-7) together with D-Ala-Ang-(1-7) (125 µg·kg(-1) ·h(-1) ) for 6 weeks. Renal vascular function was assessed in isolated perfused kidneys.. Ang-(1-7)-treated apoE (-/-) mice showed improved renal endothelium-dependent vasorelaxation induced by carbachol and increased renal basal cGMP production, compared with untreated apoE (-/-) mice. Tempol, a reactive oxygen species (ROS) scavenger, improved endothelium-dependent vasorelaxation in kidneys of saline-treated apoE (-/-) mice whereas no effect was observed in Ang-(1-7)-treated mice. Chronic treatment with D-Ala-Ang-(1-7), a specific Mas receptor antagonist, abolished the beneficial effects of Ang-(1-7) on endothelium-dependent vasorelaxation. Renal endothelium-independent vasorelaxation showed no differences between treated and untreated mice. ROS production and expression levels of the NAD(P)H oxidase subunits gp91phox and p47phox were reduced in isolated preglomerular arterioles of Ang-(1-7)-treated mice, compared with untreated mice, whereas eNOS expression was increased.. Chronic infusion of Ang-(1-7) improved renal endothelial function via Mas receptors, in an experimental model of human cardiovascular disease, by increasing levels of endogenous NO.

Topics: Angiotensin I; Angiotensin II; Animals; Antihypertensive Agents; Apolipoproteins E; Atherosclerosis; Cyclic GMP; Dose-Response Relationship, Drug; Endothelium, Vascular; Hydrogen Peroxide; Infusion Pumps, Implantable; Kidney; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Nitric Oxide; Peptide Fragments; Perfusion; Proto-Oncogene Mas; Proto-Oncogene Proteins; Receptors, G-Protein-Coupled; Vasodilation

Endothelial dysfunction plays an important role in the pathogenesis of hypertension. Other risk factors of atherosclerosis also affect its development. The aim of the study was to assess nitric oxide metabolites concentration (nitrites and nitrates No(x)) and endothelin (ET-1) in plasma and cyclic 3,5-guanosine monophosphate (cGMP) in 24 h-urine collection in patients with noncomplicated hypertension without risk factors of atherosclerosis and in hypertensive patients with coronary artery disease (CAD). Sixty-eight subjects were included in the study (44 men, 24 women), aged 47 +/- 76 years, allotted into four groups: I - controls (18 clinically healthy subjects); II - 12 subjects with hypertension without risk factors of atherosclerosis; III - 16 subjects with hypertension and risk factors of atherosclerosis; and IV - 22 subjects with hypertension and CAD. Plasma NO(x) concentration was determined using the Greiss method, plasma ET-1 by ELISA, and urine cGMP using the immunoenzymatic method. Plasma NO(x) concentration was 14.00 +/- 6.88 micromol/L in group I, in group II - 18.62 +/- 5.84 micromol, in group III - 9.96 +/- 4.72 micromol/L, and in group IV - 8.78 +/- 3.72 micromol/L. Statistically significant differences were between groups I and III (p < 0.05) and I and IV (p < 0.04) and groups II and III (p < 0.01) and II and IV (p < 0.01). The concentration of cGMP in 24 h urine collection was in group I - 40 +/- 24 pmol/L; in group II - 54 +/- 41 pmol/L; in group III - 38 +/- 32 pmol/L; and in group IV - 42 +/- 36 pmol/L. There were no significant differences between the groups. Plasma ET-1 concentration was 3.86 +/- 0.52 pg/mL in group I, in group II - 4.05 +/- 0.71 pg/mL, in group III - 4.22 +/- 0.79 pg/mL and in group IV - 4.38 +/- 0.75 pg/mL. Statistically significant differences were between group I and III (p < 0.05), I and IV (p < 0.03), and between group II and IV (p < 0.04). Endothelial dysfunction was not found in hypertensive patients without a family history of cardiovascular diseases and without other risk factors of atherosclerosis. Deterioration of endothelial function was observed in patients with hypertension with risk factors of atherosclerosis. It was most pronounced in those with CAD.

Topics: Aged; Atherosclerosis; Case-Control Studies; Coronary Artery Disease; Cyclic GMP; Endothelin-1; Endothelium, Vascular; Female; Humans; Hypertension; Male; Middle Aged; Nitrates; Nitric Oxide; Nitrites; Risk Factors; Vasodilation

Atherosclerosis is a cardiovascular disease; however, there is little information on signal transduction for vascular function in the early stage of atherosclerosis. In this work, we investigated the role of Rho/Rho-kinase and nitrogen oxide (NO)/cyclic GMP (cGMP) signaling pathways in the aorta prior to atherosclerosis.. Tension, the expression of RhoA protein, Rho-kinase activity and the cGMP level were measured using endothelium-intact or -denuded aorta prepared from apolipoprotein E-deficient (apoE-KO) and C57BL/6 wild-type (WT) mice at 2 months of age.. Phenylephrine (PE) induced less maximal contraction in the endothelium-denuded aorta from apoE-KO than from WT mice. A Rho-kinase inhibitor (Y-27632) reduced more effectively the contraction of apoE-KO than WT mice, but their RhoA proteins and Rho-kinase activities were not so different. Acetylcholine caused larger relaxation of the PE-stimulated, endothelium-intact aorta in apoE-KO due to endothelial NO release than WT mice. The basal cGMP level in the endothelium-intact aorta of apoE-KO mice was higher than that of WT.. Smooth muscle contraction via alpha(1)-adrenergic receptor shows higher dependency on Rho-kinase activity, suggesting down-regulation of the mechanism different from Rho/Rho kinase signaling in the aorta prior to atherosclerosis. Endothelium-dependent relaxation is also intensified through the NO/cGMP pathway.

Topics: Amides; Animals; Apolipoproteins E; Atherosclerosis; Cyclic GMP; Endothelium, Vascular; Humans; Mice; Mice, Inbred C57BL; Mice, Knockout; Muscle Contraction; Nitric Oxide; Pyridines; rho GTP-Binding Proteins; rho-Associated Kinases; Signal Transduction

Diet and exercise affect endothelial function in the penis, but the molecular mechanisms underlying their effects are not understood.. We evaluated endothelial nitric oxide synthase (eNOS) interaction with its negative regulator caveolin-1 and eNOS uncoupling as molecular targets in the penis associated with the beneficial effects of low-fat diet and chronic exercise.. The penes were obtained from adult male Yucatan pigs fed a normal-fat or high-fat diet on exercised or sedentary regimen for 24 weeks. Markers of endothelial function (guanosine 3',5'-monophosphate [cGMP] production), endothelial dysfunction (eNOS uncoupling and eNOS interaction with caveolin-1), and oxidative stress (thiobarbituric acid reactive substances [TBARS]) were measured in the penes. The concentrations of cGMP and TBARS were determined using commercial kits. eNOS uncoupling was determined by low-temperature sodium dodecyl sulfate polyacrylamide gel electrophoresis. eNOS binding to caveolin-1, eNOS phosphorylation (Ser-1177), and protein expression of eNOS and caveolin-1 were measured by Western blot analysis in penes purified for NOS and in homogenates, respectively.. Molecular parameters of endothelial function including eNOS regulatory function.. Relative to normal-fat diet, high-fat diet significantly (P < 0.05) reduced cGMP levels and significantly (P < 0.05) increased eNOS uncoupling, eNOS binding to caveolin-1, and TBARS production in the penis of sedentary pigs. Exercise of pigs on high-fat diet reversed (P < 0.05) the abnormalities in cGMP levels, eNOS uncoupling, and eNOS binding to caveolin-1, but not TBARS levels. Exercise of pigs on normal-fat diet did not affect any of these parameters. Protein expressions of caveolin-1, phosphorylated (Ser-1177), and total eNOS were unaffected by diet or exercise.. Low-fat diet and chronic exercise preserve endothelial function in the pig penis by sustaining active eNOS in its dimeric form and by limiting eNOS interaction with its negative regulator caveolin-1.

Topics: Animals; Atherosclerosis; Blotting, Western; Caveolin 1; Cyclic GMP; Diet, Fat-Restricted; Dietary Fats; Male; Nitric Oxide Synthase Type III; Penile Erection; Physical Conditioning, Animal; Swine; Swine, Miniature; Thiobarbituric Acid Reactive Substances; Up-Regulation

The antiatherogenic role of exercise is poorly understood. We examined the swimming exercise-induced vascular mechanisms which enhance the endothelial vasodilator function in apoE(-/-) mice. Male apoE(-/-) mice treated for 9 weeks with a lipid-rich diet were divided into two groups: the exercise group (apoE(-/-) X), which underwent a 9-week swimming protocol (50 min/day; 5days/week) and the sedentary group (apoE(-/-) S). C57BL/6 mice were used as the control group. Atherosclerotic lesions in the aortic roots were significantly reduced in apoE(-/-) X compared to apoE(-/-) S. Relaxation to acetylcholine was improved in apoE(-/-) X as compared to apoE(-/-) S and control mice with E(max) and pD(2) values significantly higher. pD(2) values in response to papaverine were higher in apoE(-/-) X than in the other groups. Relaxation in response to A23187 and DEA-NONOate were similar. These findings suggest that swimming training may increase the sensitivity of relaxation to acetylcholine, which in turn activates acetylcholine-mediated signaling pathways leading to increased NO bioactivity. Swimming may also prolong the signaling actions of NO by stimulating the sensitivity of vascular smooth muscle cells to cyclic nucleotides. These appear to be the key mechanisms underlying the improvement of the NO-cGMP pathway in exercised apoE(-/-) mice.

Topics: Acetylcholine; Animals; Aorta; Apolipoproteins E; Atherosclerosis; Cyclic GMP; Endothelium, Vascular; Hydrazines; Male; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Muscle Contraction; Muscle, Smooth, Vascular; Nitric Oxide; Nitric Oxide Donors; Physical Conditioning, Animal; Swimming; Triglycerides; Vasodilation; Vasodilator Agents

Coating a silica surface with the isolated lipoprotein receptor proteoheparan sulfate (HS-PG) from arterial endothelium and vascular matrices and adding both the atherogenic VLDL/IDL/LDL lipid fraction in its native composition and Ca(2+) ions, we could observe in vitro the earliest stages of atherosclerotic plaque development by ellipsometric techniques (patent EP 0 946 876). This so-called nanoplaque formation is represented by the ternary aggregational complex of the HS-PG receptor, lipoprotein particles and calcium ions. The model was validated in several clinical studies on statins in cardiovascular high-risk patients. In eight patients who had undergone an aortocoronary bypass operation, the reduction of atherosclerotic nanoplaque formation amounted to 11.9+/-2.5% (p<0.0078) and of nanoplaque size to 24.4+/-8.1% (p<0.0234), respectively, after a 2-month therapy with Ginkgo biloba extract (2x 120 mg daily, EGb 761). Additionally, superoxide dismutase (SOD) activity was upregulated by 15.7+/-7.0% (p<0.0391), the quotient oxLDL/LDL lowered by 17.0+/-5.5% (p<0.0234) and lipoprotein(a) concentration decreased by 23.4+/-7.9% (p<0.0234) in the patients' blood. The concentration of the vasodilating substances cAMP and cGMP was augmented by 37.5+/-9.1% (p<0.0078) and 27.7+/-8.3% (p<0.0156), respectively. A multiple regression analysis between the patients' VLDL/IDL/LDL lipoprotein fraction applied in the ellipsometry measurements as well as the further risk factors oxLDL/LDL and Lp(a) on the one hand and changes in nanoplaque formation on the other hand reveals a basis for a mechanistic explanation of nanoplaque reduction under ginkgo treatment. The atherosclerosis inhibiting effect is possibly due to an upregulation in the body's own radical scavenging enzymes and an attenuation of the risk factors oxLDL/LDL and Lp(a).

Topics: Adsorption; Aged; Atherosclerosis; Biosensing Techniques; Coronary Artery Bypass; Cyclic AMP; Cyclic GMP; Female; Ginkgo biloba; Humans; Lipoprotein(a); Lipoproteins, LDL; Male; Middle Aged; Pilot Projects; Plant Extracts; Superoxide Dismutase

Ageing is associated with an increase in atherothrombotic disease. Platelet-derived nitric oxide (NO) inhibits platelet activation, but the effect of age on platelet NO signaling is unknown. We investigated platelet NO biosynthesis and responsiveness in older (> 45 years old) as compared with younger (< 30 years old) healthy human subjects.. Platelet NO synthase (NOS) activity was evaluated by l-[3H]-arginine to l-[3H]-citrulline conversion, and cGMP was determined by radioimmunoassay. Platelet expression of NOS3, phosphoserine-1177-NOS3 and soluble guanylyl cyclase (sGC) were quantified by Western blotting. Circulating monocyte-platelet aggregates (MPA) were measured by flow cytometry.. Basal NOS activity was similar in both groups. By contrast, whereas both albuterol and collagen stimulated platelet NOS in younger subjects, stimulation was absent in older subjects. Platelet NOS3 expression was similar in both age groups, but NOS3 serine-1177 phosphorylation was greater in younger subjects. Basal, albuterol- and collagen-stimulated cGMP, as well as sGC expression, were all greater in younger than older subjects, and within the younger group both cGMP (basal and stimulated) and sGC expression were greater in women than in men. Circulating MPA were greater in older subjects and, whilst NOS inhibition increased MPA further in both groups, it did so to a lesser extent in the older age bracket.. These data suggest that platelet NO production and responsiveness decrease with age, and this is reflected in increased circulating MPA.

Topics: Adult; Age Factors; Aging; Albuterol; Atherosclerosis; Blood Platelets; Blotting, Western; Calcium; Cell Adhesion; Collagen; Cyclic GMP; Female; Guanylate Cyclase; Humans; Male; Middle Aged; Monocytes; Nitric Oxide; Nitric Oxide Synthase Type III; Platelet Adhesiveness; Risk Factors; Sex Factors; Signal Transduction; Stimulation, Chemical; Superoxides; Thrombosis

Decreased blood flow secondary to peripheral vascular disease underlies a significant number of chronic diseases that account for the majority of morbidity and mortality among the elderly. Blood vessel diameter and blood flow are limited by the matricellular protein thrombospondin-1 (TSP1) through its ability to block responses to the endogenous vasodilator nitric oxide (NO). In this study we investigate the role TSP1 plays in regulating blood flow in the presence of advanced age and atherosclerotic vascular disease.. Mice lacking TSP1 or CD47 show minimal loss of their resistance to ischemic injury with age and increased preservation of tissue perfusion immediately after injury. Treatment of WT and apolipoprotein E-null mice using therapeutic agents that decrease CD47 or enhance NO levels reverses the deleterious effects of age- and diet-induced vasculopathy and results in significantly increased tissue survival in models of ischemia.. With increasing age and diet-induced atherosclerotic vascular disease, TSP1 and its receptor CD47 become more limiting for blood flow and tissue survival after ischemic injury. Drugs that limit TSP1/CD47 regulation of blood flow could improve outcomes from surgical interventions in the elderly and ameliorate vascular complications attendant to aging.

Topics: Aging; Animals; Apolipoproteins E; Atherosclerosis; Blood Flow Velocity; CD47 Antigen; Cell Survival; Collateral Circulation; Cyclic GMP; Disease Models, Animal; Femoral Artery; Hindlimb; Ischemia; Ligation; Mice; Mice, Inbred C57BL; Mice, Knockout; Muscle, Skeletal; Necrosis; Nitric Oxide; Peripheral Vascular Diseases; Regional Blood Flow; Signal Transduction; Thrombospondin 1; Vasodilation

We have reported that inducible nitric oxide synthase (iNOS) is present only in deep areas of plaque in atherosclerosis. However, the role of iNOS in the development of atherosclerosis is not well known. We therefore investigated the relevance of iNOS inhibition.. Seven groups of male rabbits were fed a 0.5% high-cholesterol diet (HCD) for 8 weeks. Gp1-HCD was fed HCD only; Gp2-O17 was fed HCD with ONO1714, an iNOS inhibitor; Gp3-AG was fed HCD with amino-guanidine (AG), an iNOS inhibitor; Gp4-AR was fed HCD with l-arginine; Gp5-AR-O17 was fed HCD with l-arginine with ONO1714; Gp6-LNA was fed HCD with l-NAME (a NOS inhibitor); and Gp7-LN-O17 was fed HCD with l-NAME plus ONO1714. ONO1714 decreased atherosclerosis by about 70% (area occupied by lesions: 3.0+/-0.4% in Gp2-O17 versus 10.3+/-1.6% in Gp1-HCD) and also decreased atherosclerosis in Gp7-LN-O17. The ONO compound enhanced the atheroprotective effect of l-arginine. Amino-guanidine also showed an anti-atherosclerotic effect. Tone-related basal NO release and acetylcholine-induced NO-dependent relaxation were improved in Gp2-O17 and Gp5-AR-O17. O(2)(-) release was decreased in Gp2-O17 and Gp7-LN-O17.. ONO1714 retards the progression of atherosclerosis in rabbits. Although the up-regulation of endothelial nitric oxide synthase (eNOS) and the decrease of O(2)(-) may play roles in this retardation, the inhibition of iNOS may be the principal factor, alone was not sufficient.

Topics: Amidines; Animals; Aorta, Thoracic; Arginine; Atherosclerosis; Blotting, Western; Cholesterol, Dietary; Cyclic GMP; Endothelium, Vascular; Enzyme Inhibitors; Heterocyclic Compounds, 2-Ring; Immunohistochemistry; Macrophages; Male; NG-Nitroarginine Methyl Ester; Nitric Oxide; Nitric Oxide Synthase Type II; Nitric Oxide Synthase Type III; Rabbits; Reactive Oxygen Species; RNA, Messenger; Up-Regulation; Vasodilation

Activation of protein kinase C (PKC) in vascular tissue is associated with endothelial dysfunction and insulin resistance. However, the effect of vascular PKC activation on insulin-stimulated endothelial nitric oxide (NO) synthase (eNOS) regulation has not been characterized in obesity-associated insulin resistance. Diacylglycerol (DAG) concentration and PKC activity were increased in the aorta of Zucker fatty compared with Zucker lean rats. Insulin-stimulated increases in Akt phosphorylation and cGMP concentration (a measure of NO bioavailability) after euglycemic-hyperinsulinemic clamp were blunted in the aorta of fatty compared with lean rats but were partly normalized after 2 weeks of treatment with the PKCbeta inhibitor ruboxistaurin (LY333531). In endothelial cell culture, overexpression of PKCbeta1 and -beta2, but not PKCalpha, -delta, or -zeta, decreased insulin-stimulated Akt phosphorylation and eNOS expression. Overexpression of PKCbeta1 and -beta2, but not PKCalpha or -delta, also decreased Akt phosphorylation stimulated by vascular endothelial growth factor (VEGF). In microvessels isolated from transgenic mice overexpressing PKCbeta2 only in vascular cells, Akt phosphorylation stimulated by insulin was decreased compared with wild-type mice. Thus, activation of PKCbeta in endothelial cells and vascular tissue inhibits Akt activation by insulin and VEGF, inhibits Akt-dependent eNOS regulation by insulin, and causes endothelial dysfunction in obesity-associated insulin resistance.

Topics: Animals; Atherosclerosis; Blood Vessels; Cattle; Cells, Cultured; Cyclic GMP; Diglycerides; Enzyme Activation; Insulin Resistance; Male; Mice; Mice, Transgenic; Nitric Oxide Synthase Type III; Obesity; Phosphorylation; Protein Kinase C; Protein Kinase C beta; Proto-Oncogene Proteins c-akt; Rats; Rats, Zucker; Vascular Endothelial Growth Factor A