Nitric oxide (NO)-releasing statin derivatives, a class of drugs showing enhanced antiproliferative and antiinflammatory properties

Retention of Improved Plantar Sensation in Patients with Type II Diabetes Mellitus and Sensory Peripheral Neuropathy after One Month of Vibrating Insole Therapy: A Pilot Study

Sensory peripheral neuropathy is a common complication of diabetes mellitus and the biggest risk factor for diabetic foot ulcers. There is currently no available treatment that can reverse sensory loss in the diabetic population. The application of mechanical noise has been shown to improve vibration perception threshold or plantar sensation (through stochastic resonance) in the short term, but the therapeutic use, and longer-term effects have not been explored. In this study, vibrating insoles were therapeutically used by 22 participants, for 30 min per day, on a daily basis, for a month by persons with diabetic sensory peripheral neuropathy. The therapeutic application of vibrating insoles in this cohort significantly improved VPT by an average of 8.5 V (p = 0.001) post-intervention and 8.2 V (p < 0.001) post-washout. This statistically and clinically relevant improvement can play a role in protection against diabetic foot ulcers and the delay of subsequent lower-extremity amputation.

Disturbed fluid flow reinforces endothelial tractions and intercellular stresses

Disturbed fluid flow is well understood to have significant ramifications on endothelial function, but the impact disturbed flow has on endothelial biomechanics is not well understood. In this study, we measured tractions, intercellular stresses, and cell velocity of endothelial cells exposed to disturbed flow using a custom-fabricated flow chamber. Our flow chamber exposed cells to disturbed fluid flow within the following spatial zones: zone 1 (inlet; length 0.676-2.027 cm): 0.0037 ± 0.0001 Pa; zone 2 (middle; length 2.027-3.716 cm): 0.0059 ± 0.0005 Pa; and zone 3 (outlet; length 3.716-5.405 cm): 0.0051 ± 0.0025 Pa. Tractions and intercellular stresses were observed to be highest in the middle of the chamber (zone 2) and lowest at the chamber outlet (zone 3), while cell velocity was highest near the chamber inlet (zone 1), and lowest near the middle of the chamber (zone 2). Our findings suggest endothelial biomechanical response to disturbed fluid flow to be dependent on not only shear stress magnitude, but the spatial shear stress gradient as well. We believe our results will be useful to a host of fields including endothelial cell biology, the cardiovascular field, and cellular biomechanics in general.

Liquid plasma promotes angiogenesis through upregulation of endothelial nitric oxide synthase-induced extracellular matrix metabolism: potential applications of liquid plasma for vascular injuries

BACKGROUND

Applications of nonthermal plasma have expanded beyond the biomedical field to include antibacterial, anti-inflammatory, wound healing, and tissue regeneration. Plasma enhances epithelial cell repair; however, the potential damage to deep tissues and vascular structures remains under investigation.

RESULT

This study assessed whether liquid plasma (LP) increased nitric oxide (NO) production in human umbilical vein endothelial cells by modulating endothelial NO synthase (eNOS) phosphorylation and potential signaling pathways. First, we developed a liquid plasma product and confirmed the angiogenic effect of LP using the Matrigel plug assay. We found that the NO content increased in plasma-treated water. NO in plasma-treated water promoted cell migration and angiogenesis in scratch and tube formation assays via vascular endothelial growth factor mRNA expression. In addition to endothelial cell proliferation and migration, LP influenced extracellular matrix metabolism and matrix metalloproteinase activity. These effects were abolished by treatment with NG-L-monomethyl arginine, a specific inhibitor of NO synthase. Furthermore, we investigated the signaling pathways mediating the phosphorylation and activation of eNOS in LP-treated cells and the role of LKB1-adenosine monophosphate-activated protein kinase in signaling. Downregulation of adenosine monophosphate-activated protein kinase by siRNA partially inhibited LP-induced eNOS phosphorylation, angiogenesis, and migration.

CONCLUSION

The present study suggests that LP treatment may be a novel strategy for promoting angiogenesis in vascular damage. Video Abstract.

Microvascular Function and Exercise Training: Functional Implication of Nitric Oxide Signaling and Ion Channels

Background

Exercise training elicits indubitable positive adaptation in microcirculation in health and disease populations. An inclusive overview of the current knowledge regarding the effects of exercise on microvascular function consolidates an in-depth understanding of microvasculature.

Summary

The main physiological function of microvasculature is to maintain optimal blood flow regulation to supply oxygen and nutrition during elevated physical demands in the cardiovascular system. There are several cellular and molecular alterations in resistance vessels in response to exercise intervention, an increase in nitric oxide-mediated vasodilation through the regulation of oxidative stress, inflammatory response, and ion channels in endothelial cells, thus increasing myogenic tone via voltage-gated Ca2+ channels in smooth muscle cells.

Key Messages

In the review, we postulate that exercise should be considered a medicine for people with diverse diseases through a comprehensive understanding of the cellular and molecular underlying mechanisms in microcirculation through exercise training.

Predictive value of oxidant and antioxidant status for contrast-induced nephropathy after percutaneous coronary intervention for ST-segment elevation myocardial infarction

BACKGROUND

Contrast-induced nephropathy (CIN) is a life-threatening complication after primary percutaneous coronary intervention (p-PCI). Oxidative stress and inflammation may play an important role in the development of CIN.

OBJECTIVE

We aimed to assess the relationship between total oxidant status, total antioxidant capacity, high-sensitivity C-reactive protein (hs-CRP), gamma-glutamyltransferase and uric acid (UA) in the development of CIN in patients presenting with ST-elevation myocardial infarction (STEMI).

METHODS

This prospective cohort study consisted of 341 patients with STEMI. Patients were divided into two groups: those with and those without CIN. Predictors of CIN were determined by multivariate regression analyses.

RESULTS

Multivariate regression analysis showed that initial glucose level, contrast media volume/glomerular filtration ratio (eGFR) ratio, hs-CRP, UA and oxidative status index were associated with the development of CIN in patients with STEMI.

CONCLUSION

The main finding of this study is that increased oxidative stress and inflammation parameters were associated with the development of CIN in patients with STEMI. Other independent predictors of CIN were contrast media volume/eGFR ratio, initial glucose level, UA and hs-CRP.

Visualizing the Underlying Signaling Pathway Related to Nitric Oxide and Glutathione in Cardiovascular Disease Therapy by a Sequentially Activated Fluorescent Probe

Clarifying the signaling pathway associated with nitric oxide (NO) and glutathione (GSH) in cardiovascular disease therapy is important for understanding its physiological and pathological processes but is challenging due to the lack of efficient analytical techniques. Herein, we report a BODIPY-based fluorescent probe for recognition of NO and GSH in sequence with high sensitivity and selectivity. The probe exhibits turn-on fluorescence triggered by NO, followed by red-shifted emission in the presence of GSH. The sequentially activated mechanism allows the visualization of NO-induced GSH upregulation in drug-treated endothelial cells and zebrafish for the first time, revealing a signal pathway during the therapy. We hope that it can be used as a convenient and efficient tool for the study of the interplay between NO and GSH and for the screening of effective drugs for cardiovascular disease therapy.

Shear Stress and RBC-NOS Serine1177 Phosphorylation in Humans: A Dose Response

Red blood cells (RBC) express a nitric oxide synthase isoform (RBC-NOS) that appears dependent on shear stress for Serine1177 phosphorylation. Whether this protein is equally activated by varied shears in the physiological range is less described. Here, we explored RBC-NOS Serine1177 phosphorylation in response to shear stress levels reflective of in vivo conditions. Whole blood samples were exposed to specific magnitudes of shear stress (0.5, 1.5, 4.5, 13.5 Pa) for discrete exposure times (1, 10, 30 min). Thereafter, RBC-NOS Serine1177 phosphorylation was measured utilising immunofluorescence labelling. Shear stress exposure at 0.5, 1.5, and 13.5 Pa significantly increased RBC-NOS Serine1177 phosphorylation following 1 min (p < 0.0001); exposure to 4.5 Pa had no effect after 1 min. RBC-NOS Serine1177 phosphorylation was significantly increased following 10 min at each magnitude of shear stress (0.5, 1.5, 13.5 Pa, p < 0.0001; 4.5 Pa, p = 0.0042). Shear stress exposure for 30 min significantly increased RBC-NOS Serine1177 phosphorylation at 0.5 Pa and 13.5 Pa (p < 0.0001). We found that RBC-NOS phosphorylation via shear stress is non-linear and differs for a given magnitude and duration of exposure. This study provides a new understanding of the discrete relation between RBC-NOS and shear stress.

Statin-Induced Nitric Oxide Signaling: Mechanisms and Therapeutic Implications

In addition to their cholesterol-lowering effects, statins are associated with pleiotropic effects including improvements in heart failure (HF), reduced blood pressure, prevention of the rupture of atherosclerotic plaques and improved angiogenesis. In addition to these cardiovascular benefits, statins have been implicated in the treatment of neurological injuries, cancer, sepsis, and cirrhosis. These cholesterol-independent beneficial effects of statins are predominantly mediated through signaling pathways leading to increased production and bioavailability of nitric oxide (NO). In this review, the mechanistic pathways and therapeutic effects of statin-mediated elevations of NO are described and discussed.

Deletion of Robo4 prevents high-fat diet-induced adipose artery and systemic metabolic dysfunction

OBJECTIVE

Accumulating evidence suggests the vascular endothelium plays a fundamental role in the pathophysiology of obesity by regulating the functional status of white adipose and systemic metabolism. Robo4 is expressed specifically in endothelial cells and increases vascular stability and inhibits angiogenesis. We sought to determine the role of Robo4 in modulating cardiometabolic function in response to high-fat feeding.

METHODS

We examined exercise capacity, glucose tolerance, and white adipose tissue artery gene expression, endothelium-dependent dilation (EDD), and angiogenesis in wild type and Robo4 knockout (KO) mice fed normal chow (NC) or a high-fat diet (HFD).

RESULTS

We found Robo4 deletion enhances exercise capacity in NC-fed mice and HFD markedly increased the expression of the Robo4 ligand, Slit2, in white adipose tissue. Deletion of Robo4 increased angiogenesis in white adipose tissue and protected against HFD-induced impairments in white adipose artery vasodilation and glucose intolerance.

CONCLUSIONS

We demonstrate a novel functional role for Robo4 in endothelial cell function and metabolic homeostasis in white adipose tissue, with Robo4 deletion protecting against endothelial and metabolic dysfunction associated with a HFD. Our findings suggest that Robo4-dependent signaling pathways may be a novel target in anti-obesity therapy.

cGMP at the centre of attention: emerging strategies for activating the cardioprotective PKG pathway

The nitric oxide (NO)-protein kinase G (PKG) pathway has been known for some time to be an important target for cardioprotection against ischaemia/reperfusion injury and heart failure. While many approaches for reducing infarct size in patients have failed in the past, the advent of novel drugs that modulate cGMP and its downstream targets shows very promising results in recent preclinical and clinical studies. Here, we review main aspects of the NO-PKG pathway in light of recent drug development and summarise potential cardioprotective strategies in which cGMP is the main player.

Endothelial Cell Autonomous Role of Akt1: Regulation of Vascular Tone and Ischemia-Induced Arteriogenesis

OBJECTIVE

The importance of PI3K/Akt signaling in the vasculature has been demonstrated in several models, as global loss of Akt1 results in impaired postnatal ischemia- and VEGF-induced angiogenesis. The ubiquitous expression of Akt1, however, raises the possibility of cell-type-dependent Akt1-driven actions, thereby necessitating tissue-specific characterization.

APPROACH AND RESULTS

Herein, we used an inducible, endothelial-specific Akt1-deleted adult mouse model (Akt1iECKO) to characterize the endothelial cell autonomous functions of Akt1 in the vascular system. Endothelial-targeted ablation of Akt1 reduces eNOS (endothelial nitric oxide synthase) phosphorylation and promotes both increased vascular contractility in isolated vessels and elevated diastolic blood pressures throughout the diurnal cycle in vivo. Furthermore, Akt1iECKO mice subject to the hindlimb ischemia model display impaired blood flow and decreased arteriogenesis.

CONCLUSIONS

Endothelial Akt1 signaling is necessary for ischemic resolution post-injury and likely reflects the consequence of NO insufficiency critical for vascular repair.

Rosuvastatin Treatment for Preventing Contrast-Induced Acute Kidney Injury After Cardiac Catheterization: A Meta-Analysis of Randomized Controlled Trials

We performed a meta-analysis of randomized controlled trials (RCTs) to evaluate the protective effects of rosuvastatin on contrast-induced acute kidney injury (CI-AKI) and major adverse cardiovascular events (MACEs) in patients undergoing cardiac catherization.PubMed, MEDLINE, Web of Science, EMBASE, ClinicalTrials.gov, and the Cochrane Central RCTs were searched for RCTs from inception to May 2015, to compare rosuvastatin for preventing CI-AKI with placebo treatment in patients undergoing cardiac catherization.Five RCTs with a total of 4045 patients involving 2020 patients pretreated with rosuvastatin and 2025 control patients were identified and analyzed. Patients treated with rosuvastatin had a 51% lower risk of CI-AKI compared with the control group based on a fixed-effect model (OR = 0.49, 95% CI = 0.37-0.66, P < 0.001), and showed a trend toward a reduced risk of MACEs (OR = 0.62, 95% CI = 0.36-1.07, P = 0.08). A subgroup analysis showed that studies with Jadad score ≥3 showed a significant reduction of CI-AKI (OR = 0.53, 95% CI, 0.38-0.73, P < 0.001). However, the risk of CI-AKI did not significantly differ in the studies with Jadad score <3 (OR = 0.54, 95% CI, 0.13-2.24, P = 0.40). In addition, the rosuvastatin treatment showed no effect for preventing CI-AKI in patients with chronic kidney disease (CKD) undergoing elective cardiac catherization (I = 0%, OR = 0.81, 95% CI = 0.41-1.61, P = 0.55).This updated meta-analysis demonstrated that preprocedural rosuvastatin treatment could significantly reduce the incidence of CI-AKI, with a trend toward a reduced risk of MACEs in patients undergoing cardiac catheterization. However, rosuvastatin treatment did not seem to be effective for preventing CI-AKI in CKD patients undergoing elective cardiac catheterization.

Characterization of the anti-inflammatory properties of NCX 429, a dual-acting compound releasing nitric oxide and naproxen

AIMS

Cyclooxygenase (COX)-inhibiting nitric oxide donors (CINODs) are a new class of drugs that structurally combine a COX inhibitor with a nitric oxide (NO) donating moiety. This combination reduces potential toxicity of the non-steroidal anti-inflammatory drugs (NSAIDs) whilst maintaining the analgesic and anti-inflammatory effects. The present study was undertaken to investigate the anti-inflammatory effects of NCX 429, a naproxen-based CINOD, and to assess the additional properties of NO donation beyond those related to naproxen.

MAIN METHODS

We evaluated the in vitro effects of NCX 429 on oxy-radical production, phagocytosis, cytokine release, MMP-9, PPARγ expression and NF-κB activation in human monocytes/MDM and compared to naproxen. Moreover, we compared the in vivo efficacy of NCX 429 and naproxen in a murine model of peritonitis.

KEY FINDINGS

In all the experiments performed in vitro, NCX 429 reduced the inflammatory responses with equal or higher efficacy compared to naproxen. Moreover, in in vivo experiments, NCX 429, at the lowest dose tested, was able to significantly inhibit cell influx in response to IL-1β administration although naproxen was found to be more potent than NCX 429 at reducing PGE2 in inflammatory exudates.

SIGNIFICANCE

These results demonstrate that both in vitro and in vivo--in a murine model of peritonitis--NCX 429 elicits significant anti-inflammatory activity, beyond the simple COX inhibition or pure NO release. Therefore, NO donation along with COX inhibition may represent a strategy for investigating inflammatory diseases in which pain and function are not fully resolved by analgesics/anti-inflammatory drugs.

Recent developments in the effects of nitric oxide-donating statins on cardiovascular disease through regulation of tetrahydrobiopterin and nitric oxide

Since the discovery of the importance of nitric oxide (NO) to the human body three decades ago, numerous laboratory and clinical studies have been done to explore its potential therapeutic actions on many organs. In the cardiovascular system, NO works as a volatile signaling molecule regulating the vascular permeability and vascular tone, preventing thrombosis and inflammation, as well as inhibiting the smooth muscle hyperplasia. Thus, NO is important in the prevention and treatment of cardiovascular disease. NO is synthesized by NO synthase (NOS) with tetrahydrobiopterin (BH4) as the crucial cofactor. Many studies have been done to form nitric oxide donors so as to deliver NO directly to the vessel walls. In addition, NO moieties have been incorporated into existing therapeutic agents to enhance the NO bioavailability, including statins. Statins are inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme (HMG-CoA), the rate-limiting enzyme of the mevalonate pathway. By inhibiting this pathway, statins lower blood cholesterol and exert their pleiotropic effects through activity in reaction cascades, such as Rho/ROCK and Rac 1/NADPH oxidase pathways. Statins have also been observed to implement their non-lipid effects by promoting BH4 synthesis with increase of NO bioavailability. Furthermore, NO-donating statins in laboratory studies have demonstrated to produce better therapeutic effects than their parent's drugs. They offer better anti-inflammatory, anti-proliferative and antithrombotic actions on cardiovascular system. They also cause better revascularization in peripheral ischemia and produce greater enhancement in limb reperfusion and salvage. In addition, it has been shown that NO-donating statin caused less myotoxicity, the most common side effect related to treatment with statins. The initial studies have demonstrated the superior therapeutic effects of NO-donating statins while producing fewer side effects.

Statins and nitric oxide donors affect thrombospondin 1-induced chemotaxis

BACKGROUND

Thrombospondin 1 (TSP-1) induces vascular smooth muscle cell (VSMC) migration and intimal hyperplasia. Statins and nitric oxide (NO) donors decrease intimal hyperplasia. We previously showed that statins (long-term exposure) and NO donors inhibit TSP-1-induced VSMC chemotaxis.

HYPOTHESES

(1) Pretreatment with short-term statin will inhibit TSP-1-induced VSMC chemotaxis and (2) NO donors will enhance statin inhibition of TSP-1-induced or platelet-derived growth factor (PDGF)-induced VSMC chemotaxis.

METHODS

We examined these treatment effects on TSP-1-induced VSMC chemotaxis: (1) long-term (20 hours) versus short-term (20 minutes) pravastatin, (2) diethylenetriamine NONOate (DETA/NO) or S-nitroso-N-acetylpenicillamine (SNAP) in combination with pravastatin, and (3) comparison of TSP-1 to PDGF as a chemoattractant.

RESULTS

Pravastatin (long term or short term) inhibited TSP-1-induced chemotaxis. Diethylenetriamine NONOate and SNAP impeded statin inhibition of TSP-1-induced chemotaxis. Platelet-derived growth factor and TSP-1 had opposite effects on DETA/NO-pravastatin treatment.

CONCLUSION

Short-term statin pretreatment inhibited TSP-1-induced VSMC chemotaxis, suggesting a pleiotropic effect. High-dose NO reversed statin inhibition of TSP-1-induced chemotaxis, suggesting NO and statin combination therapies warrant further study.

Comparison of the efficacy of rosuvastatin versus atorvastatin in preventing contrast induced nephropathy in patient with chronic kidney disease undergoing percutaneous coronary intervention

Objectives

We prospectively compared the preventive effects of rosuvastatin and atorvastatin on contrast-induced nephropathy (CIN) in patients with chronic kidney disease (CKD) undergoing percutaneous coronary intervention (PCI).

Methods

We enrolled 1078 consecutive patients with CKD undergoing elective PCI. Patients in Group 1 (n = 273) received rosuvastatin (10 mg), and those in group 2 (n = 805) received atorvastatin (20 mg). The primary end-point was the development of CIN, defined as an absolute increase in serum creatinine ≥0.5 mg/dL, or an increase ≥25% from baseline within 48–72 h after contrast medium exposure.

Results

CIN was observed in 58 (5.4%) patients. The incidence of CIN was similar in patients pretreated with either rosuvastatin or atorvastatin (5.9% vs. 5.2%, p = 0.684). The same results were also observed when using other definitions of CIN. Clinical and procedural characteristics did not show significant differences between the two groups (p>0.05). Additionally, there were no significant inter-group differences with respect to in-hospital mortality rates (0.4% vs. 1.5%, p = 0.141), or other in-hospital complications. Multivariate logistic regression analysis revealed that rosuvastatin and atorvastatin demonstrated similar efficacies for preventing CIN, after adjusting for potential confounding risk factors (odds ratio = 1.17, 95% confidence interval, 0.62–2.20, p = 0.623). A Kaplan–Meier survival analysis showed that patients taking either rosuvastatin or atorvastatin had similar incidences of all-cause mortality (9.4% vs. 7.1%, respectively; p = 0.290) and major adverse cardiovascular events (29.32% vs. 23.14%, respectively; p = 0.135) during follow-up.

Conclusions

Rosuvastatin and atorvastatin have similar efficacies for preventing CIN in patients with CKD undergoing PCI.

LDL cholesterol as a novel risk factor for contrast-induced acute kidney injury in patients undergoing percutaneous coronary intervention

BACKGROUND

Low density lipoprotein cholesterol (LDL-C) is associated with endothelial dysfunction, inflammation and increased vasoconstriction, which are involved in the development of contrast-induced acute kidney injury (CI-AKI). However, whether LDL-C is an independent risk factor of CI-AKI in patients undergoing percutaneous coronary intervention (PCI) is unknown.

METHODS

We prospectively enrolled 3236 consecutive patients undergoing PCI between January 2010 and September 2012. Multivariate logistic regression analysis was used to determine whether LDL-C is an independent risk factor of CI-AKI. CI-AKI was defined as an absolute increase in serum creatinine of ≥ 0.5 mg/dL or ≥ 25% over the baseline value within 48-72 h after contrast exposure.

RESULTS

CI-AKI was observed in 338 patients (10.4%). Patients with CI-AKI had a significantly higher rate of in hospital mortality (4.4% vs. 0.5%, p < 0.001), and significantly higher rates of other in hospital complications compared with those without CI-AKI. The LDL-C quartiles were as follows: Q1 (<2.04 mmol/L), Q2 (2.04-2.61 mmol/L), Q3 (2.61-3.21 mmol/L) and Q4 (>3.21 mmol/L). Patients with high baseline LDL-C levels were more likely to develop CI-AKI and composite end points including all-cause mortality, renal replacement therapy, non-fatal myocardial infarction, acute heart failure, target vessel revascularization or cerebrovascular accident during the observation period of hospitalization (8.9%, 9.9%, 10.5%, 12.6%, p = 0.001, and 5.0%, 5.2%, 6.1%, 8.1%, respectively; p = 0.007). Univariate logistic analysis showed that LDL-C levels (increment 1 mmol/L) were significantly associated with CI-AKI (odds ratio = 1.25, 95% confidence interval (CI), 1.11-1.39, p < 0.001). Furthermore, LDL-C remained a significant risk factor of CI-AKI (odds ratio = 1.23, 95% CI, 1.04-1.45, p = 0.014), even after adjusting for potential confounding risk factors.

CONCLUSIONS

Measurement of plasma LDL-C concentrations in patients undergoing PCI may be helpful to identify those who are at risk of CI-AKI and poor in hospital outcomes.

Fluvastatin attenuated the effect of expression of β1 integrin in PAN-treated podocytes by inhibiting reactive oxygen species

It is well accepted that β1 integrin plays a key role in maintaining normal podocytes form and functions; however, its mechanism of the potential protective effect remains unclear. Furthermore, the investigation and understanding of the non-lipid-dependent renal protection of Statins in addition to well-known lipid-lowering effect may provide the therapeutic utility and ultimately improve clinical outcome for patients with renal diseases. In the present study, we investigated the effect and mechanism of fluvastatin (FLV) on the expression of β1 integrin in puromycin aminonucleoside (PAN)-treated podocytes in vitro. Cultured human podocytes were treated with PAN, and/or different concentrations of FLV (1 × 10(-8)-1 × 10(-5 )mol/l), superoxide dismutase (SOD), or H2O2, respectively. The expression of β1 integrin and reactive oxygen species (ROS) in human podocytes under each experimental condition was evaluated by western blot, RT-PCR, and 2'7'-dichlorofluorescein 3'6'-diacetate, respectively. The viability of podocytes was also assessed by MTT colorimetry in the present study. The expression of β1 integrin was significantly decreased, and the synthesis of ROS was significantly increased in podocytes following either PAN or H2O2 treatment (p < 0.05). The up-regulation of β1 integrin and down-regulation of ROS were also observed in PAN-treated podocytes following lower concentrations of FLV or SOD treatment (p < 0.05, respectively). The cytotoxicity data derived from MTT assay revealed that lower podocyte viability was found in the presence of higher concentrations of FLV, PAN, or H2O2. Lower concentration of FLV or SOD can protect podocytes from being impaired by PAN treatment. FLV attenuated the podocyte injury induced by PAN and increased the production of β1 integrin in human podocytes in vitro. This underlying mechanism of FLV may be through inhibiting the activity of ROS in human podocytes.

Statins for the Prevention of Contrast-Induced Nephropathy After Coronary Angiography/Percutaneous Interventions: A Meta-analysis of Randomized Controlled Trials

BACKGROUND

Statins have been demonstrated to prevent the development of contrast-induced nephropathy (CIN). Nevertheless, clinical research has indicated conflicting results. We performed a meta-analysis of randomized controlled trials (RCTs) to evaluate the protective effects of statins on CIN and the requirement of renal replacement therapy (RRT) in patients undergoing coronary angiography/percutaneous interventions.

METHODS

PubMed, MEDLINE, Web of Science, EMBASE, ClinicalTrials.gov, and the Cochrane Central RCTs were searched for RCTs from inception to February 2014 to compare statins with placebo treatment for preventing CIN in patients undergoing coronary angiography/percutaneous interventions.

RESULTS

Nine RCTs were identified and analyzed in a total of 5143 patients involving 2560 patients with statin pretreatment and 2583 patients as control. Patients who received statin therapy had a 53% lower risk of CIN with different definitions (within 48 or 72 hours) compared to the control group based on a fixed effect model (risk ratio = 0.47, 95% confidence interval = 0.37-0.60, P < .0001) and were less likely to require RRT based on Peto fixed effect. Subgroup analysis showed that statin pretreatment could decrease the incidence of CIN in patients with preexisting renal dysfunction or diabetes mellitus. In addition, patients on rosuvastatin had a similar reduced incidence of CIN compared to patients on atorvastatin.

CONCLUSION

This updated meta-analysis demonstrated that preprocedural statin treatment could reduce the risk of CIN and the need for RRT in patients undergoing coronary angiography/percutaneous interventions. Moreover, statin therapy would be helpful in reducing the incidence of CIN in high-risk patients with preexisting renal dysfunction or diabetes mellitus. Additionally, rosuvastatin and atorvastatin had similar efficacies in preventing CIN development.

Nitric oxide-donating atorvastatin attenuates neutrophil recruitment during vascular inflammation independent of changes in plasma cholesterol

PURPOSE

Polymorphonuclear neutrophils, the first leukocytes to infiltrate the inflamed tissue, can make important contributions to vascular inflammatory processes driving the development of atherosclerosis. We herein investigated the effects of atorvastatin and NCX 6560 (a nitric oxide (NO)-donating atorvastatin derivative that has completed a successful phase 1b study) on neutrophilic inflammation in carotid arteries of normocholesterolemic rabbits subjected to perivascular collar placement.

METHODS

Atorvastatin or NCX 6560 were administered orally (5 mg/kg/day or equimolar dose) to New Zealand White rabbits for 6 days, followed by collar implantation 1 h after the last dose. Twenty-four hours later carotids were harvested for neutrophil quantification by immunostaining.

RESULTS

Treatment with NCX 6560 was associated with a lower neutrophil infiltration (-39.5 %), while atorvastatin did not affect neutrophil content. The result was independent of effects on plasma cholesterol or differences in atorvastatin bioavailability, which suggests an important role of NO-related mechanisms in mediating this effect. Consistent with these in vivo findings, in vitro studies showed that NCX 6560, as compared to atorvastatin, had greater inhibitory activity on processes involved in neutrophil recruitment, such as migration in response to IL-8 and IL-8 release by endothelial cells and by neutrophils themselves. Pretreatment with NCX 6560, but not with atorvastatin, reduced the ability of neutrophil supernatants to promote monocyte chemotaxis, a well-known pro-inflammatory activity of neutrophils.

CONCLUSION

Experimental data suggest a potential role of NO-releasing statins in the control of the vascular inflammatory process mediated by polymorphonuclear neutrophils.

[In vitro study over statins effects on cellular growth curves and its reversibility with mevalonate]

HMG-CoA-Reductase inhibitors, also known as statins, are currently the most powerful cholesterol-lowering drugs available on the market. Clinical trials and experimental evidence suggest that statins have heavy anti-atherosclerotic effects. These are in part consequence of lipid lowering but also result from pleiotropic actions of the drugs. These so-called pleiotropic properties affect various aspects of cell function, inflammation, coagulation, and vasomotor activity. These effects are mediated either indirectly through LDL-c reduction or via a direct effect on cellular functions. Although many of the pleiotropic properties of statins may be a class effect, some may be unique to certain agents and account for differences in their pharmacological activity. So, although statins typically have similar effects on LDL-c levels, differences in chemical structure and pharmacokinetic profile can lead to variations in pleiotropic effects. In this paper we analize the in vitro effects of different statins over different cell lines from cells implicated in atherosclerotic process: endothelial cells, fibroblasts, and vascular muscular cells. In relation with our results we can proof that the effects of different dosis of different statins provides singular effects over growth curves of different cellular lines, a despite of a class-dependent effects. So, pleiotropic effects and its reversibility with mevalonate are different according with the molecule and the dosis.

Nitric oxide prevents atorvastatin-induced skeletal muscle dysfunction and alterations in mice

INTRODUCTION

Myopathy is the most common side effect of statins. Because nitric oxide (NO) has a key role in regulating skeletal muscle function, we studied whether the NO-donating atorvastatin NCX 6560 could show a better profile on skeletal muscle function and structure compared with atorvastatin.

METHODS

C57BL/6 mice received atorvastatin 40 mg/kg/day or an equivalent dose of NCX 6560 for 2 months. Muscle function assessed by treadmill test, serum creatine kinase (CK) activity, citrate synthase (CS) activity, and muscle histology were evaluated.

RESULTS

Atorvastatin significantly (P < 0.001) reduced muscle endurance, increased serum CK by 6-fold, and induced muscle fiber atrophy. Conversely, NCX 6560 preserved muscle function, prevented CK increase and did not modify muscle structure. Interestingly, atorvastatin reduced CS activity, a marker for mitochondrial function, in gastrocnemius, diaphragm, and heart, whereas NCX 6560 prevented such decrease.

CONCLUSIONS

These findings suggest that NO may prevent statin-induced myopathy.

Pleiotropic effects of pitavastatin

3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) are established first line treatments for hypercholesterolaemia. In addition to the direct effects of statins in reducing concentrations of atherogenic low density lipoprotein cholesterol (LDL-C), several studies have indicated that the beneficial effects of statins may be due to some of their cholesterol-independent, multiple (pleiotropic) effects which may differ between different members of the class. Pitavastatin is a novel synthetic lipophilic statin that has a number of pharmacodynamic and pharmacokinetic properties distinct from those of other statins, which may underlie its potential pleiotropic benefits in reducing cardiovascular risk factors. This review examines the principal pleiotropic effects of pitavastatin on endothelial function, vascular inflammation, oxidative stress and thrombosis. The article is based on a systematic literature search carried out in December 2010, together with more recent relevant publications where appropriate. The available data from clinical trials and in vitro and animal studies suggest that pitavastatin is not only effective in reducing LDL-C and triglycerides, but also has a range of other effects. These include increasing high density lipoprotein cholesterol, decreasing markers of platelet activation, improving cardiac, renal and endothelial function, and reducing endothelial stress, lipoprotein oxidation and, ultimately, improving the signs and symptoms of atherosclerosis. It is concluded that the diverse pleiotropic actions of pitavastatin may contribute to reducing cardiovascular morbidity and mortality beyond that achieved through LDL-C reduction.

Nitric oxide-donating statin improves multiple functions of circulating angiogenic cells

BACKGROUND AND PURPOSE

Statins, a major component of the prevention of cardiovascular disease, aid progenitor cell functions in vivo and in vitro. Statins bearing a NO-releasing moiety were developed for their enhanced anti-inflammatory/anti-thrombotic properties. Here, we investigated if the NO-donating atorvastatin (NCX 547) improved the functions of circulating angiogenic cells (CACs).

EXPERIMENTAL APPROACH

Circulating angiogenic cells (CACs) were prepared from peripheral blood monocytes of healthy volunteers and type-2 diabetic patients and were cultured in low (LG) or high glucose (HG) conditions, in presence of atorvastatin or NCX 547 (both at 0.1 µM) or vehicle. Functional assays (outgrowth, proliferation, viability, senescence and apoptosis) were performed in presence of the endothelial NOS inhibitor L-NIO, the NO scavenger c-PTIO or vehicle.

KEY RESULTS

Culturing in HG conditions lowered NO in CACs, inhibited outgrowth, proliferation, viability and migration, and induced cell senescence and apoptosis. NCX 547 fully restored NO levels and functions of HG-cultured CACs, while atorvastatin prevented only apoptosis in CACs. The activity of Akt, a pro-survival kinase, was increased by atorvastatin in LG-cultured but not in HG-cultured CACs, whereas NCX 547 increased Akt activity in both conditions. L-NIO partially blunted and c-PTIO prevented NCX 547-induced improvements in CAC functions. Finally, NCX 547 improved outgrowth and migration of CACs prepared from patients with type 2 diabetes.

CONCLUSIONS AND IMPLICATIONS

NCX 547 was more effective than atorvastatin in preserving functions of CACs. This property adds to the spectrum of favourable actions that would make NO-releasing statins more effective agents for treating cardiovascular disease.

Nitric oxide enhances the anti-inflammatory and anti-atherogenic activity of atorvastatin in a mouse model of accelerated atherosclerosis

AIMS

The aim of the present study was to assess whether the addition of a nitric oxide (NO)-donating moiety to atorvastatin enhances anti-inflammatory and anti-atherogenic effects in an animal model of endothelial dysfunction, systemic peroxidation and inflammation, and accelerated atherosclerosis.

METHODS AND RESULTS

Low-density lipoprotein receptor (LDLR)(-/-) mice kept on a high-fat diet (HFD) for 16 weeks underwent photochemical injury to the femoral artery with the local production of oxygen radicals. HFD markedly enhanced cholesterol, inflammatory biomarkers in plasma and in the femoral arterial wall, and atherosclerotic lesions in the aortic arch; inflammation and atherosclerosis were further increased by photochemically generated oxygen radicals. Treatment with the NO-donating atorvastatin NCX 6560 (11.7 mg/kg) was significantly more effective than atorvastatin (10 mg/kg) in reducing the following parameters: lipid-rich lesions in the aortic arch (surface covered: atorvastatin = 24 ± 5%; NCX 6560 = 14.7 ± 3.9%; P< 0.05); the production of radical oxygen species in the aorta (dichlorofluorescein fluorescence intensity per milligram of protein: atorvastatin = 2419 ± 136.7; NCX 6560 = 1766 ± 161.2; P< 0.05); femoral artery intima/media thickness (atorvastatin = 1.2 ± 0.11; NCX 6560 = 0.3 ± 0.14; P< 0.05); circulating interleukin-6 (atorvastatin = 34.3 ± 6.8 pg/mL; NCX 6560 = 17.7 ± 14.4 pg/mL; P< 0.05); and matrix metalloproteinase 2 in the arterial wall (atorvastatin = 55.2 ± 1.9 ng/µg of proteins; NCX 6560 = 45.8 ± 2.6 ng/µg of proteins; P < 0.05).

CONCLUSION

In conditions of severe endothelial dysfunction, systemic peroxidation and inflammation, and accelerated atherosclerosis, atorvastatin, even at high doses, displays suboptimal anti-atherogenic and anti-inflammatory effects, while the addition of a NO-donating property confers enhanced anti-atherogenic and anti-inflammatory effects.

Pleiotropic effects of statins in distal human pulmonary artery smooth muscle cells

BACKGROUND

Recent clinical data suggest statins have transient but significant effects in patients with pulmonary arterial hypertension. In this study we explored the molecular effects of statins on distal human pulmonary artery smooth muscle cells (PASMCs) and their relevance to proliferation and apoptosis in pulmonary arterial hypertension.

METHODS

Primary distal human PASMCs from patients and controls were treated with lipophilic (simvastatin, atorvastatin, mevastatin and fluvastatin), lipophobic (pravastatin) and nitric-oxide releasing statins and studied in terms of their DNA synthesis, proliferation, apoptosis, matrix metalloproteinase-9 and endothelin-1 release.

RESULTS

Treatment of human PASMCs with selected statins inhibited DNA synthesis, proliferation and matrix metalloproteinase-9 production in a concentration-dependent manner. Statins differed in their effectiveness, the rank order of anti-mitogenic potency being simvastatin > atorvastatin > > pravastatin. Nevertheless, a novel nitric oxide-releasing derivative of pravastatin (NCX 6550) was effective. Lipophilic statins, such as simvastatin, also enhanced the anti-proliferative effects of iloprost and sildenafil, promoted apoptosis and inhibited the release of the mitogen and survival factor endothelin-1. These effects were reversed by mevalonate and the isoprenoid intermediate geranylgeranylpyrophosphate and were mimicked by inhibitors of the Rho and Rho-kinase.

CONCLUSIONS

Lipophilic statins exert direct effects on distal human PASMCs and are likely to involve inhibition of Rho GTPase signalling. These findings compliment some of the recently documented effects in patients with pulmonary arterial hypertension.

Pediatric pulmonary arterial hypertension: current and emerging therapeutic options

INTRODUCTION

Pulmonary arterial hypertension (PAH) is a rare disease in neonates, infants and children that is associated with significant morbidity and mortality. An adequate understanding of the controlling pathophysiologic mechanisms is lacking and although mortality has decreased as therapeutic options have increased over the past several decades, outcomes remain unacceptable.

AREAS COVERED

This review summarizes the currently available therapies for neonates, infants and children with PAH and describes emerging therapies in the context of what is known about the underlying pathophysiology of the disease.

EXPERT OPINION

All of the currently approved PAH therapies impact one of three endothelial-based pathways: nitric oxide-guanosine-3'-5'cyclic monophosphate, prostacyclin or endothelin-1. The beneficial effects of these agents may relate to their impact on pulmonary vascular tone, and/or their antiproliferative and antithrombotic properties. Fundamental advances in PAH therapy are likely to relate to: i) a better understanding of PAH subpopulations, allowing for therapies to be better tailored to individual patients and pathophysiologic processes; and ii) therapies that promote the regression of advanced structural remodeling.

Nitric oxide affects IL-6 expression in human peripheral blood mononuclear cells involving cGMP-dependent modulation of NF-κB activity

Interleukin 6 (IL-6) and nitric oxide (NO) are important mediators of the inflammatory response. We report that in human peripheral blood mononuclear cells (PBMCs), NO exerts a biphasic effect on the expression of IL-6. Using sodium nitroprusside (SNP) and S-nitrosoglutathione (GSNO) as NO-donating compounds, we observed that both mRNA and protein levels of IL-6 increased at lower (≤10μM) and decreased at higher (>100μM) concentrations of NO donors. Changes in the expression of IL-6 correlated with changes in the activity of NF-κB, which increased at lower and decreased at higher concentrations of both NO donors as shown by the electrophoretic mobility shift assay (EMSA). The effects of NO on NF-κB activity were cGMP-dependent because they were reversed in the presence of ODQ, the inhibitor of soluble guanylyl cyclase (sGC), and KT5823, the inhibitor of cGMP-dependent protein kinase (PKG). Moreover, the membrane permeable analog of cGMP (8-Br-cGMP) mimicked the effect of the NO donors. These observations show that NO, depending on its concentration, may act in human PBMCs as a stimulator of IL-6 expression involving the sGC/cGMP/PKG pathway.

A novel nitric oxide releasing prostaglandin analog, NCX 125, reduces intraocular pressure in rabbit, dog, and primate models of glaucoma

PURPOSE

Nitric oxide (NO) is involved in a variety of physiological processes including ocular aqueous humor dynamics by targeting mechanisms that are complementary to those of prostaglandins. Here, we have characterized a newly synthesized compound, NCX 125, comprising latanoprost acid and NO-donating moieties.

METHODS

NCX 125 was synthesized and tested in vitro for its ability to release functionally active NO and then compared with core latanoprost for its intraocular pressure (IOP)-lowering effects in rabbit, dog, and nonhuman primate models of glaucoma.

RESULTS

NCX 125 elicited cGMP formation (EC(50) = 3.8 + or - 1.0 microM) in PC12 cells and exerted NO-dependent iNOS inhibition (IC(50) = 55 + or - 11 microM) in RAW 264.7 macrophages. NCX 125 lowered IOP to a greater extent compared with equimolar latanoprost in: (a) rabbit model of transient ocular hypertension (0.030% latanoprost, not effective; 0.039% NCX 125, Delta(max) = -10.6 + or - 2.3 mm Hg), (b) ocular hypertensive glaucomatous dogs (0.030% latanoprost, Delta(max)= -6.7 + or - 1.2 mm Hg; 0.039% NCX 125, Delta(max) = -9.1 + or - 3.1 mm Hg), and (c) laser-induced ocular hypertensive non-human primates (0.10% latanoprost, Delta(max) = -11.9 + or - 3.7 mm Hg, 0.13% NCX 125, Delta(max) = -16.7 + or - 2.2 mm Hg). In pharmacokinetic studies, NCX 125 and latanoprost resulted in similar latanoprost-free acid exposure in anterior segment ocular tissues.

CONCLUSIONS

NCX 125, a compound targeting 2 different mechanisms, is endowed with potent ocular hypotensive effects. This may lead to potential new perspectives in the treatment of patients at risk of glaucoma.

Atorvastatin preconditioning attenuates the production of endothelin-1 and prevents experimental vasospasm in rats

OBJECTIVE

Induced endothelin-1 (ET-1) production and decreased nitric oxide synthase (NOS) bioavailability have been found in aneurysmal subarachnoid hemorrhage (SAH). Atorvastatin is recognized to have pleiotropic effects including increasing NOS bioavailability as well as reducing inflammation and oxidative damage other than reducing dyslipidemia. This study is of interest to examine the effect of atorvastatin on ET-1/endothelial nitric oxide synthase (eNOS) in experimental SAH.

METHODS

A rodent double-hemorrhage SAH model was employed. Animals were randomly assigned as sham-operated, SAH, vehicle plus SAH, 5 mg/day atorvastatin treatment plus SAH and 5 mg/day atorvastatin precondition plus SAH groups. Administration with atorvastatin (5 mg/day) was initiated 1 week before (precondition) and 24 hr later (treatment). Cerebrospinal fluid samples were collected at 72 hr after second SAH. ET-1 (ELISA) was measured. The basilar arteries (BAs) were harvested and sliced, and their cross-sectional areas were measured. Radiolabeled NOS assay kit was used to detect eNOS.

RESULTS

Morphologically, convoluted internal elastic lamina, distorted endothelial cells and myonecrosis of the smooth muscle were predominantly observed in the BA of SAH and vehicle-treated SAH groups, which was not detected in the atorvastatin-preconditioned SAH group or the healthy controls. Significant vasospasm was noted in the vehicle group (lumen potency 64.5%, compared with the sham group, p </= 0.01) and less prominent in the atorvastatin treatment group (lumen potency, 76.6%, p < 0.05). In addition, increased ET-1 levels were found in all the animals subject to SAH (SAH only, SAH plus vehicle and SAH plus atorvastatin reversal) except in the atorvastatin precognition group when compared with the healthy controls (no SAH). Likewise, the levels of expressed NOS in BAs is induced in the atorvastatin groups (both atorvastatin treatment and precondition) when compared with that in the SAH group (p < 0.01).

CONCLUSION

This study offers first evidence that atorvastatin in the preconditioning status reduces the level of ET-1, which corresponds to its antivasospastic effect in the condition of chronic vasospasm. Although there is increased expression of NOS in both atorvastatin precondition and reversal groups, BA's lumen potency is significantly increased in the atorvastatin precondition group when compared with the SAH group (p < 0.01).

COX-2 expression is unexpectedly high in viable colorectal mucosal cells: is there life for chemoprophylaxis after VICTOR?

INTRODUCTION

Trials investigating colorectal cancer (CRC) chemoprophylaxis with cyclooxygenase-2 (COX-2) inhibitors have been discontinued because of adverse cardiovascular effects. Nevertheless, identification of patients where beneficial, chemo-prophylactic effects of COX-2 inhibitors outweigh side-effects may be possible; this study aimed to investigate whether such patient groups might exist.

METHOD

The COX-2 status of viable epithelial and inflammatory cells in freshly disaggregated CRC and paired normal colonic samples was assessed by three-colour flow cytometry.

RESULTS

21/31 (67.7%) CRCs expressed COX-2, with inflammatory cells positive in 19/31 (61.3%), epithelial cells in 12/31 (38.7%), and both positive in 10/31 (32.3%). 25/30 (83.33%) normal samples expressed COX-2, with epithelial cells positive in 18/30 (60%), inflammatory cells in 15/30 (50%) and both positive in 10/30 (33.3%). Strength of expression by CRC and normal was similar. More advanced cancers had higher expression rates (COX-2 in 12/13 (92.3%) with nodal disease vs 9/17 (52.9%) node-negative; P = 0.04).

CONCLUSION

Investigation of ex-vivo CRC cells by flow cytometry demonstrated COX-2 expression rates comparable to that previously reported. However, expression by paired live normal colon was significantly greater, suggesting that COX-2 may be expressed at higher rates in normal colonic cells in patients with CRC. Patients identified at resection as expressing COX-2 in normal colon may benefit from Coxib chemo-prophylaxis, thus potentially offering a refined approach to that adopted in the VICTOR trial.

NCX 2057, a novel NO-releasing derivative of ferulic acid, suppresses inflammatory and nociceptive responses in in vitro and in vivo models

BACKGROUND AND PURPOSE

We previously reported that NCX 2057, a compound comprising a nitric oxide (NO)-releasing moiety and the natural antioxidant, ferulic acid (FA), inhibits pro-inflammatory mediators through NO-mediated gene regulation. Here, we have assessed the activities of NCX 2057 in models of inflammatory and neuropathic pain, and characterized its effects on cyclooxygenase (COX)-1 and COX-2.

EXPERIMENTAL APPROACH

Anti-nociceptive and anti-inflammatory activities of NCX 2057 were measured in vitro and in vivo in models of inflammatory (carrageenan) and neuropathic (chronic constriction injury; CCI) pain. Effects of NCX 2057 were measured on COX-1 and COX-2 activities in RAW 264.7 macrophages.

KEY RESULTS

NCX 2057 dose-dependently inhibited single motor unit responses to noxious mechanical stimulation (ID(50)= 100 micromol kg(-1)) and wind-up responses in rats with paw inflammation induced by carrageenan. Moreover, NCX 2057 inhibited allodynic responses following CCI of the sciatic nerve [ipsilateral Paw Withdrawal Threshold (g): vehicle: 41.4 +/- 3.3; NCX 2057: 76.3 +/- 4.8 FA: 37.9 +/- 15.5 at 175 micromol kg(-1)]. NCX 2057 reversed carrageenan-induced hyperalgesic responses in mice and inhibited prostaglandin E(2) formation in paw exudates. Finally, NCX 2057 competitively inhibited COX-1 and COX-2 activities in whole RAW macophages (IC(50)= 14.7 +/- 7.4 and 21.6 +/- 7.5 microM, respectively). None of these properties were exhibited by equivalent treatments with FA or standard NO donor compounds.

CONCLUSIONS AND IMPLICATIONS

These studies indicate that NCX 2057 is effective in chronic inflammatory and neuropathic pain models, probably because of its particular combination of anti-COX, antioxidant and NO-releasing properties.

Cyclic GMP signaling in cardiovascular pathophysiology and therapeutics

Cyclic guanosine 3',5'-monophosphate (cGMP) mediates a wide spectrum of physiologic processes in multiple cell types within the cardiovascular system. Dysfunctional signaling at any step of the cascade - cGMP synthesis, effector activation, or catabolism - have been implicated in numerous cardiovascular diseases, ranging from hypertension to atherosclerosis to cardiac hypertrophy and heart failure. In this review, we outline each step of the cGMP signaling cascade and discuss its regulation and physiologic effects within the cardiovascular system. In addition, we illustrate how cGMP signaling becomes dysregulated in specific cardiovascular disease states. The ubiquitous role cGMP plays in cardiac physiology and pathophysiology presents great opportunities for pharmacologic modulation of the cGMP signal in the treatment of cardiovascular diseases. We detail the various therapeutic interventional strategies that have been developed or are in development, summarizing relevant preclinical and clinical studies.

Inhibitory effects of NO-fluvastatin on proliferation of human lens epithelial cells in vitro by modulating cell cycle regulatory proteins

The effects of NO-Fluvastatin on proliferation of human lens epithelial cells (HLECs) and the action mechanism were investigated. Cell proliferation was assessed by MTT assay. Cell cycle was analyzed by flow cytometry. The expression of cell cycle regulatory proteins CyclinE mRNA and P21(waf1) mRNA was detected by reverse transcription polymerase chain reaction (RT-PCR). MTT staining colorimetry showed that HLECs proliferation was markedly inhibited by NO-Fluvastatin and the effect was dependently related to time (24, 48 and 72 h) and dosage (1, 5 and 20 mumol/L). Flow cytometry revealed that NO-Fluvastatin could significantly block HLECs in the G(0)/G(1) phase, resulting in the increased cells in the G(0)/G(1) phase and decreased in the S phase (P<0.05). RT-PCR showed that NO-Fluvastatin could obviously inhibit the CyclinE mRNA expression and induce the P21(waf1) mRNA expression as compared with the negative control groups (P<0.05). This experiment suggested that NO-Fluvastatin could suppress the proliferation of HLECs by regulating cell cycle regulatory proteins (inhibiting the expression of CyclinE mRNA and inducing the expression of P21(waf1) mRNA), resulting in the arrest of HLECs in the G(0)/G(1) phase, which can offer theory basis for NO-Fluvastatin in treating posterior capsular opacification in clinic practice.

Fluvastatin reduces pulmonary vein spontaneous activity through nitric oxide pathway

INTRODUCTION

Pulmonary veins (PVs) are the most important focus for the generation of atrial fibrillation. The HMG-CoA reductase inhibitors (statins) can reduce the occurrence of atrial fibrillation. The purposes of this study were to evaluate whether statins may inhibit the PV arrhythmogenic activity to prevent atrial arrhythmias from PVs and to investigate the link between fluvastatin, nitric oxide synthase (NOS) activity, mechanical activity, and electrical activity.

METHODS

Conventional microelectrodes and Western blot were used to record the electrical activity, diastolic tension, contractility and expression of Akt, endothelial nitric oxide synthase (eNOS), neuronal nitric oxide synthase (nNOS), and phosphorylated Akt and eNOS before and after the administration of fluvastatin in rabbit PVs or atria.

RESULTS

Fluvastatin decreased the PV spontaneous activity, diastolic tension, and contractility, but did not change the action potential duration or resting membrane potential. The effects of fluvastatin on the PV firing rate and diastolic tension were attenuated in the presence of L-NAME (100 microM), wortmannin (100 nM), and ODQ (3 microM). Fluvastatin (1 muM) increased the phosphorylated Akt and eNOS, but did not change the total Akt or eNOS in the PVs and atria. In contrast, fluvastatin (1 microM) decreased the total nNOS in the PVs and atria.

CONCLUSIONS AND IMPLICATIONS

Fluvastatin produced nitric oxide through the PI3kinase/Akt pathway, thus reducing the PV vascular diastolic tension and PV spontaneous activity. These results may contribute to the beneficial effects of statins.

Nitric oxide in the vasculature: where does it come from and where does it go? A quantitative perspective

Nitric oxide (NO) affects two key aspects of O2 supply and demand: It regulates vascular tone and blood flow by activating soluble guanylate cyclase (sGC) in the vascular smooth muscle, and it controls mitochondrial O2 consumption by inhibiting cytochrome c oxidase. However, significant gaps exist in our quantitative understanding of the regulation of NO production in the vascular region. Large apparent discrepancies exist among the published reports that have analyzed the various pathways in terms of the perivascular NO concentration, the efficacy of NO in causing vasodilation (EC50), its efficacy in tissue respiration (IC50), and the paracrine and endocrine NO release. In this study, we review the NO literature, analyzing NO levels on various scales, identifying and analyzing the discrepancies in the reported data, and proposing hypotheses that can potentially reconcile these discrepancies. Resolving these issues is highly relevant to improving our understanding of vascular biology and to developing pharmaceutical agents that target NO pathways, such as vasodilating drugs.