Diverse effects of inhibition of 3-hydroxy-3-methylglutaryl-CoA reductase on the expression of VCAM-1 and E-selectin in endothelial cells

Cerebral Malaria and Neuronal Implications of Plasmodium Falciparum Infection: From Mechanisms to Advanced Models

Reorganization of host red blood cells by the malaria parasite Plasmodium falciparum enables their sequestration via attachment to the microvasculature. This artificially increases the dwelling time of the infected red blood cells within inner organs such as the brain, which can lead to cerebral malaria. Cerebral malaria is the deadliest complication patients infected with P. falciparum can experience and still remains a major public health concern despite effective antimalarial therapies. Here, the current understanding of the effect of P. falciparum cytoadherence and their secreted proteins on structural features of the human blood-brain barrier and their involvement in the pathogenesis of cerebral malaria are highlighted. Advanced 2D and 3D in vitro models are further assessed to study this devastating interaction between parasite and host. A better understanding of the molecular mechanisms leading to neuronal and cognitive deficits in cerebral malaria will be pivotal in devising new strategies to treat and prevent blood-brain barrier dysfunction and subsequent neurological damage in patients with cerebral malaria.

Statin Use in Hospitalized Patients with COVID-19: A Comprehensive Analysis of the New York City Public Hospital System

INTRODUCTION

Statins have been commonly used for primary and secondary cardiovascular prevention. We hypothesized that statins may improve in-hospital outcomes for hospitalized patients with Coronavirus disease 2019 (COVID-19) due to its known anti-inflammatory effects.

METHODS

We conducted a retrospective study at the largest municipal health care system in the United States, including adult patients who were hospitalized for COVID-19 between March 1 and December 1, 2020. The primary endpoint was in-hospital death. Propensity score matching was conducted to balance possible confounding variables between patients receiving statins during hospitalization (statin group) and those not receiving statins (non-statin group). Multivariate logistic regression was used to evaluate the association of statin use and other variables with in-hospital outcomes.

RESULTS

There were 8897 patients eligible for study enrollment, with 3359 patients in the statin group and 5538 patients in the non-statin group. After propensity score matching, both the statin and non-statin groups included 2817 patients. Multivariate logistic regression analysis showed that the statin group had a significantly lower risk of in-hospital mortality (odds ratio 0.71; 95% confidence interval, 0.63-0.80; P < .001) and mechanical ventilation (OR 0.80; 95% confidence interval, 0.71-0.90; P < .001) compared with the non-statin group.

CONCLUSION

Statin use was associated with lower likelihood of in-hospital mortality and invasive mechanical ventilation in hospitalized patients with COVID-19.

IL-1β and Statin Treatment in Patients with Myocardial Infarction and Diabetic Cardiomyopathy

Statins are effective lipid-lowering drugs with a good safety profile that have become, over the years, the first-line therapy for patients with dyslipidemia and a real cornerstone of cardiovascular (CV) preventive therapy. Thanks to both cholesterol-related and “pleiotropic” effects, statins have a beneficial impact against CV diseases. In particular, by reducing lipids and inflammation statins, they can influence the pathogenesis of both myocardial infarction and diabetic cardiomyopathy. Among inflammatory mediators involved in these diseases, interleukin (IL)-1β is a pro-inflammatory cytokine that recently been shown to be an effective target in secondary prevention of CV events. Statins are largely prescribed to patients with myocardial infarction and diabetes, but their effects on IL-1β synthesis and release remain to be fully characterized. Of interest, preliminary studies even report IL-1β secretion to rise after treatment with statins, with a potential impact on the inflammatory microenvironment and glycemic control. Here, we will summarize evidence of the role of statins in the prevention and treatment of myocardial infarction and diabetic cardiomyopathy. In accordance with the dual lipid-lowering and anti-inflammatory effect of these drugs and in light of the important results achieved by IL-1β inhibition through canakinumab in CV secondary prevention, we will dissect the current evidence linking statins with IL-1β and outline the possible benefits of a potential double treatment with statins and canakinumab.

Lovastatin exerts protective effects on endothelial cells via upregulation of PTK2B

Statins are HMG-CoA reductase inhibitors that are used to decrease the blood levels of low-density lipoprotein (LDL). In addition, they have been shown to exert pleiotropic protective effects in the absence of LDL-lowering activity. The present study investigated the effects of lovastatin on global gene expression in human umbilical vein endothelial cells (HUVECs), in order to further explore its ability to protect against oxidized (ox)-LDL-induced cytotoxicity. HUVECs were treated with lovastatin for 2–24 h, and gene expression patterns were analyzed using cDNA microarrays. The results suggested that numerous genes were regulated by lovastatin, including certain genes associated with cell survival, such as PTK2B, BCL2 and MAP3K3. In particular, PTK2B, which has been shown to exert anti-apoptotic effects against ox-LDL-induced cell injury, was upregulated by lovastatin. Knockdown of PTK2B was able to attenuate ox-LDL-induced cell injury, and this was associated with decreased levels of phosphorylated-AKT and eNOS, and inhibition of mitochondrial-dependent apoptosis. In conclusion, the results of the present study suggested that lovastatin protects against ox-LDL-induced cell injury, potentially via the upregulation of PTK2B, which regulates the anti-apoptosis signaling pathway.

Effects of simvastatin and taurine on delayed cerebral vasospasm following subarachnoid hemorrhage in rabbits

The aim of the current study was to observe the effects of simvastatin and taurine on delayed cerebral vasospasm (DCVS) following experimental subarachnoid hemorrhage (SAH) in rabbits. A total of 48 New Zealand white rabbits were allocated at random into four groups (control, SAH, SAH + simvastatin and SAH + taurine groups; n=12 each). The rabbit model of DCVS was established using a double hemorrhage method, which involved injecting autologous arterial blood into the cisterna magna in the SAH groups. The SAH + simvastatin group was administered oral simvastatin (5 mg/kg) daily between days 0-6. The SAH + taurine group was administered oral taurine (50 mg/kg) daily between days 0-6. Starch (50 mg/kg) was administered orally to the animals in the other two groups (control and SAH groups). The control group were not subjected to any other injections or treatment. The internal diameter and internal diameter/wall thickness of the basilar artery (BA) were measured. The expression levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 were determined using immunohistochemical and quantitative polymerase chain reaction methods following the sacrifice of all animals on day 7. The activity of nuclear factor (NF)-κB in the BA was also measured using an electrophoretic mobility shift assay. The BA walls in the SAH + simvastatin and SAH + taurine groups exhibited reduced narrowing and corrugation of the tunica elastica interna compared with the SAH group. At the protein and cDNA levels, it was found that cerebral vasospasm of the BA in the SAH + simvastatin and SAH + taurine groups was alleviated, as indicated by the reduced expression of TNF-α, IL-1β, IL-6 and NF-κB compared with the SAH group (P<0.05). In conclusion, simvastatin and taurine reduced DCVS following SAH in rabbits, which suggests that these compounds may exert anti-inflammatory effects.

The cumulative effect of assisted reproduction procedures on placental development and epigenetic perturbations in a mouse model

Assisted reproductive technologies (ART) are associated with several complications including low birth weight, abnormal placentation and increased risk for rare imprinting disorders. Indeed, experimental studies demonstrate ART procedures independent of existing infertility induce epigenetic perturbations in the embryo and extraembryonic tissues. To test the hypothesis that these epigenetic perturbations persist and result in adverse outcomes at term, we assessed placental morphology and methylation profiles in E18.5 mouse concepti generated by in vitro fertilization (IVF) in two different genetic backgrounds. We also examined embryo transfer (ET) and superovulation procedures to ascertain if they contribute to developmental and epigenetic effects. Increased placental weight and reduced fetal-to-placental weight ratio were observed in all ART groups when compared with naturally conceived controls, demonstrating that non-surgical embryo transfer alone can impact placental development. Furthermore, superovulation further induced overgrowth of the placental junctional zone. Embryo transfer and superovulation defects were limited to these morphological changes, as we did not observe any differences in epigenetic profiles. IVF placentae, however, displayed hypomethylation of imprinting control regions of select imprinted genes and a global reduction in DNA methylation levels. Although we did not detect significant differences in DNA methylation in fetal brain or liver samples, rare IVF concepti displayed very low methylation and abnormal gene expression from the normally repressed allele. Our findings suggest that individual ART procedures cumulatively increase placental morphological abnormalities and epigenetic perturbations, potentially causing adverse neonatal and long-term health outcomes in offspring.

Anticoagulants and Statins As Pharmacological Agents in Free Flap Surgery: Current Rationale

Microvascular free flaps are key components of reconstructive surgery, but despite their common use and usual reliability, flap failures still occur. Many pharmacological agents have been utilized to minimize risk of flap failure caused by thrombosis. However, the challenge of most antithrombotic therapy lies in providing patients with optimal antithrombotic prophylaxis without adverse bleeding effects. There is a limited but growing body of evidence suggesting that the vasoprotective and anti-inflammatory actions of statins can be beneficial for free flap survival. By inhibiting mevalonic acid, the downstream effects of statins include reduction of inflammation, reduced thrombogenicity, and improved vasodilation. This review provides a summary of the pathophysiology of thrombus formation and the current evidence of anticoagulation practices with aspirin, heparin, and dextran. In addition, the potential benefits of statins in the perioperative management of free flaps are highlighted.

The many roles of statins in ischemic stroke

Stroke is the third leading cause of human death. Endothelial dysfunction, thrombogenesis, inflammatory and oxidative stress damage, and angiogenesis play an important role in cerebral ischemic pathogenesis and represent a target for prevention and treatment. Statins have been found to improve endothelial function, modulate thrombogenesis, attenuate inflammatory and oxidative stress damage, and facilitate angiogenesis far beyond lowering cholesterol levels. Statins have also been proved to significantly decrease cardiovascular risk and to improve clinical outcome. Could statins be the new candidate agent for the prevention and therapy in ischemic stroke? In recent years, a vast expansion in the understanding of the pathophysiology of ischemic stroke and the pleiotropic effects of statins has occurred and clinical trials involving statins for the prevention and treatment of ischemic stroke have begun. These facts force us to revisit ischemic stroke and consider new strategies for prevention and treatment. Here, we survey the important developments in the non-lipid dependent pleiotropic effects and clinical effects of statins in ischemic stroke.

99mTc-cAbVCAM1-5 imaging is a sensitive and reproducible tool for the detection of inflamed atherosclerotic lesions in mice

(99m)Tc-cAbVCAM1-5, a single-domain antibody fragment directed against mouse or human vascular cell adhesion molecule 1 (VCAM-1), recently has been proposed as a new imaging agent for the detection of inflamed atherosclerotic lesions. Indeed, in a mouse model of atherosclerosis, (99m)Tc-cAbVCAM1-5 specifically bound to VCAM-1-positive lesions, thereby allowing their identification on SPECT images. The purpose of the present study was to investigate (99m)Tc-cAbVCAM1-5 imaging sensitivity using a reference statin therapy.

METHODS

Thirty apolipoprotein E-deficient mice were fed a western-type diet. First, the relationship between the level of VCAM-1 expression and (99m)Tc-cAbVCAM1-5 uptake was evaluated in 18 mice using immunohistochemistry and autoradiography. Second, longitudinal SPECT/CT imaging was performed on control (n = 9) or atorvastatin-treated mice (0.01% w/w, n = 9).

RESULTS

(99m)Tc-cAbVCAM1-5 uptake in atherosclerotic lesions correlated with the level of VCAM-1 expression (P < 0.05). Atorvastatin exerted significant antiatherogenic effects, and (99m)Tc-cAbVCAM1-5 lesion uptake was significantly reduced in 35-wk-old atorvastatin-treated mice, as indicated by ex vivo γ-well counting and autoradiography (P < 0.05). SPECT imaging quantification based on contrast-enhanced CT was reproducible (interexperimenter intraclass correlation coefficient, 0.97; intraexperimenter intraclass correlation coefficient, 0.90), and yielded results that were highly correlated with tracer biodistribution (r = 0.83; P < 0.0001). Therefore, reduced (99m)Tc-cAbVCAM1-5 uptake in atorvastatin-treated mice was successfully monitored noninvasively by SPECT/CT imaging (0.87 ± 0.06 vs. 1.11 ± 0.09 percentage injected dose per cubic centimeter in control group, P < 0.05).

CONCLUSION

(99m)Tc-cAbVCAM1-5 imaging allowed the specific, sensitive, and reproducible quantification of VCAM-1 expression in mouse atherosclerotic lesions. (99m)Tc-cAbVCAM1-5 therefore exhibits suitable characteristics for the evaluation of novel antiatherogenic agents.

Effect of statins on endothelial function in patients with acute coronary syndrome: a prospective study using adhesion molecules and flow-mediated dilatation

Background

Accumulating evidence suggests that inflammatory mechanisms play a central role in the development, progression and outcome of atherosclerosis. Recent evidence suggests that statins improve anti-inflammatory, anti-thrombotic and endothelial functions, along with their lipid-decreasing effects. We examined the effect of statins on endothelial function using biochemical markers of endothelial dysfunction and brachial artery flow-mediated dilatation (FMD).

Methods

Thirty male patients presenting with acute coronary syndrome (ACS) and 26 age-matched healthy control subjects aged 40 - 60 years who were not on any medication were enrolled in the study. The patient group was started on atorvastatin (40 mg/day) without consideration of their low-density lipoprotein (LDL)-cholesterol levels. Endothelin, sICAM and E-selectin from stored serum samples were measured using commercially available enzyme-linked immunosorbant assays (ELISAs). Endothelial function was assessed using brachial artery FMD.

Results

Prior to statin treatment, E-selectin, sICAM and endothelin levels, endothelial dysfunction markers, were 99.74 ± 34.67 ng/mL, 568.8 ± 149.0 ng/mL and 0.62 ± 0.33 fmol/mL, respectively in the patient group. E-selectin and sICAM levels were significantly higher in the patients than in the control subjects (P < 0.001); however, endothelin levels were not significantly different between groups. Statin treatment significantly reduced E-selectin and sICAM levels (P < 0.001); however, the decrease in endothelin levels was not statistically significant. %FMD values were significantly increased after statin treatment (P = 0.005), and levels of C-reactive protein (CRP), an inflammation marker, were significantly reduced.

Conclusion

Our results indicate that statins play an important role in treatment endothelial dysfunction by reducing adhesion of inflammatory cells.

Statins role in the prevention and treatment of sepsis

Sepsis is a complex disease with typically poor outcomes. While the onset of sepsis is typically infectious, the detrimental consequences follow pathogen toxin release that produces activation of numerous cytokines and a pro-inflammatory response. These same cytokines also stimulate activation of coagulation and inhibit natural fibrinolysis. Despite decades of research targeted against these pathways the development of sepsis and mortality in patients with sepsis remains high. While statins were developed for reducing cholesterol in patients with atherosclerotic disease, we now know they have a number of other properties which may be helpful in the prevention and treatment of sepsis. Statins have demonstrated the ability to reduce a number of pro-inflammatory cytokines known to be detrimental in the development and progression of sepsis. Statins have also demonstrated the ability to limit the coagulation response and promote fibrinolysis in the setting of sepsis. Based on these encouraging pharmacologic properties of statins a number of trials have been conducted evaluating the impact of statins on the prevention and treatment of sepsis. Most of the trials to date have been retrospective cohort trials, with very few prospective randomized trials. While some trials fail to demonstrate a benefit of statins, most trials suggest a reduction in the development of sepsis and/or other important sepsis related outcomes. While the laboratory and early clinical experience with statins are encouraging, randomized controlled trials will be need to fully define the role of statins in the prevention and treatment of sepsis.

Dual-modal magnetic resonance and fluorescence imaging of atherosclerotic plaques in vivo using VCAM-1 targeted tobacco mosaic virus

The underlying cause of major cardiovascular events, such as myocardial infarctions and strokes, is atherosclerosis. For accurate diagnosis of this inflammatory disease, molecular imaging is required. Toward this goal, we sought to develop a nanoparticle-based, high aspect ratio, molecularly targeted magnetic resonance (MR) imaging contrast agent. Specifically, we engineered the plant viral nanoparticle platform tobacco mosaic virus (TMV) to target vascular cell adhesion molecule (VCAM)-1, which is highly expressed on activated endothelial cells at atherosclerotic plaques. To achieve dual optical and MR imaging in an atherosclerotic ApoE(-/-) mouse model, TMV was modified to carry near-infrared dyes and chelated Gd ions. Our results indicate molecular targeting of atherosclerotic plaques. On the basis of the multivalency and multifunctionality, the targeted TMV-based MR probe increased the detection limit significantly; the injected dose of Gd ions could be further reduced 400x compared to the suggested clinical use, demonstrating the utility of targeted nanoparticle cargo delivery.

CTCF binding site sequence differences are associated with unique regulatory and functional trends during embryonic stem cell differentiation

CTCF (CCCTC-binding factor) is a highly conserved multifunctional DNA-binding protein with thousands of binding sites genome-wide. Our previous work suggested that differences in CTCF’s binding site sequence may affect the regulation of CTCF recruitment and its function. To investigate this possibility, we characterized changes in genome-wide CTCF binding and gene expression during differentiation of mouse embryonic stem cells. After separating CTCF sites into three classes (LowOc, MedOc and HighOc) based on similarity to the consensus motif, we found that developmentally regulated CTCF binding occurs preferentially at LowOc sites, which have lower similarity to the consensus. By measuring the affinity of CTCF for selected sites, we show that sites lost during differentiation are enriched in motifs associated with weaker CTCF binding in vitro. Specifically, enrichment for T at the 18^th position of the CTCF binding site is associated with regulated binding in the LowOc class and can predictably reduce CTCF affinity for binding sites. Finally, by comparing changes in CTCF binding with changes in gene expression during differentiation, we show that LowOc and HighOc sites are associated with distinct regulatory functions. Our results suggest that the regulatory control of CTCF is dependent in part on specific motifs within its binding site.

Dietary carbohydrate restriction improves insulin sensitivity, blood pressure, microvascular function, and cellular adhesion markers in individuals taking statins

Statins positively impact plasma low-density lipoprotein cholesterol, inflammation and vascular endothelial function (VEF). Carbohydrate restricted diets (CRD) improve atherogenic dyslipidemia, and similar to statins, have been shown to favorably affect markers of inflammation and VEF. No studies have examined whether a CRD provides additional benefit beyond that achieved by habitual statin use. We hypothesized that a CRD (<50 g carbohydrate/d) for 6 weeks would improve lipid profiles and insulin sensitivity, reduce blood pressure, decrease cellular adhesion and inflammatory biomarkers, and augment VEF (flow-mediated dilation and forearm blood flow) in statin users. Participants (n = 21; 59.3 ± 9.3 y, 29.5 ± 3.0 kg/m(2)) decreased total caloric intake by approximately 415 kcal at 6 weeks (P < .001). Daily nutrient intakes at baseline (46/36/17% carb/fat/pro) and averaged across the intervention (11/58/28% carb/fat/pro) demonstrated dietary compliance, with carbohydrate intake at baseline nearly 5-fold greater than during the intervention (P < .001). Compared to baseline, both systolic and diastolic blood pressure decreased after 3 and 6 weeks (P < .01). Peak forearm blood flow, but not flow-mediated dilation, increased at week 6 compared to baseline and week 3 (P ≤ .03). Serum triglyceride, insulin, soluble E-Selectin and intracellular adhesion molecule-1 decreased (P < .01) from baseline at week 3, and this effect was maintained at week 6. In conclusion, these findings demonstrate that individuals undergoing statin therapy experience additional improvements in metabolic and vascular health from a 6 weeks CRD as evidenced by increased insulin sensitivity and resistance vessel endothelial function, and decreased blood pressure, triglycerides, and adhesion molecules.

Noninvasive ultrasound molecular imaging of the effect of statins on endothelial inflammatory phenotype in early atherosclerosis

BACKGROUND/OBJECTIVES

Inflammatory changes on the endothelium are responsible for leukocyte recruitment to plaques in atherosclerosis. Noninvasive assessment of treatment-effects on endothelial inflammation may be of use for managing medical therapy and developing novel therapies. We hypothesized that molecular imaging of vascular cell adhesion molecule-1 (VCAM-1) with contrast enhanced ultrasound (CEU) could assess treatment effects on endothelial phenotype in early atherosclerosis.

METHODS

Mice with atherosclerosis produced by gene deletion of the LDL-receptor and Apobec-1-editing protein were studied. At 12 weeks of age, mice received 8 weeks of regular chow or atorvastatin-enriched chow (10 mg/kg/day). At 20 weeks, CEU molecular imaging for aortic endothelial VCAM-1 expression was performed with VCAM-1-targeted (MB(VCAM)) and control microbubbles (MB(Ctr)). Aortic wall thickness was assessed with high frequency ultrasound. Histology, immunohistology and Western blot were used to assess plaque burden and VCAM-1 expression.

RESULTS

Plaque burden was reduced on histology, and VCAM-1 was reduced on Western blot by atorvastatin, which corresponded to less endothelial expression of VCAM-1 on immunohistology. High frequency ultrasound did not detect differences in aortic wall thickness between groups. In contrast, CEU molecular imaging demonstrated selective signal enhancement for MB(VCAM) in non-treated animals (MB(VCAM) 2±0.3 vs MB(Ctr) 0.7±0.2, p<0.01), but not in statin-treated animals (MB(VCAM) 0.8±0.2 vs MB(Ctr) 1.0±0.2, p = ns; p<0.01 for the effect of statin on MB(VCAM) signal).

CONCLUSIONS

Non-invasive CEU molecular imaging detects the effects of anti-inflammatory treatment on endothelial inflammation in early atherosclerosis. This easily accessible, low-cost technique may be useful in assessing treatment effects in preclinical research and in patients.

HOXA9 methylation by PRMT5 is essential for endothelial cell expression of leukocyte adhesion molecules

The induction of proinflammatory proteins in stimulated endothelial cells (EC) requires activation of multiple transcription programs. The homeobox transcription factor HOXA9 has an important regulatory role in cytokine induction of the EC-leukocyte adhesion molecules (ELAM) E-selectin and vascular cell adhesion molecule 1 (VCAM-1). However, the mechanism underlying stimulus-dependent activation of HOXA9 is completely unknown. Here, we elucidate the molecular mechanism of HOXA9 activation by tumor necrosis factor alpha (TNF-α) and show an unexpected requirement for arginine methylation by protein arginine methyltransferase 5 (PRMT5). PRMT5 was identified as a TNF-α-dependent binding partner of HOXA9 by mass spectrometry. Small interfering RNA (siRNA)-mediated depletion of PRMT5 abrogated stimulus-dependent HOXA9 methylation with concomitant loss in E-selectin or VCAM-1 induction. Chromatin immunoprecipitation analysis revealed that PRMT5 is recruited to the E-selectin promoter following transient HOXA9 binding to its cognate recognition sequence. PRMT5 induces symmetric dimethylation of Arg140 on HOXA9, an event essential for E-selectin induction. In summary, PRMT5 is a critical coactivator component in a newly defined, HOXA9-containing transcription complex. Moreover, stimulus-dependent methylation of HOXA9 is essential for ELAM expression during the EC inflammatory response.

Atorvastatin treatment is effective when used in combination with mefloquine in an experimental cerebral malaria murine model

BACKGROUND

One of the major complications of Plasmodium falciparum infection is cerebral malaria (CM), which causes one million deaths worldwide each year, results in long-term neurological sequelae and the treatment for which is only partially effective. Statins are recognized to have an immunomodulatory action, attenuate sepsis and have a neuroprotective effect. Atorvastatin (AVA) has shown in vitro anti-malarial activity and has improved the activity of mefloquine (MQ) and quinine.

METHODS

The efficiency of 40 mg/kg intraperitoneal AVA, alone or in association with MQ, was assessed in an experimental Plasmodium berghei ANKA rodent parasite model of CM and performed according to different therapeutic schemes. The effects on experimental CM were assessed through the evaluation of brain histopathological changes and neuronal apoptosis by TUNEL staining.

RESULTS

AVA alone in the therapeutic scheme show no effect on survival, but the prophylactic scheme employing AVA associated with MQ, rather than MQ alone, led to a significant delay in mouse death and had an effect on the onset of CM symptoms and on the level of parasitaemia. Histopathological findings show a correlation between brain lesions and CM onset. A neuronal anti-apoptotic effect of AVA in the AVA + MQ combination was not shown.

CONCLUSIONS

The combination of AVA and MQ therapy led to a significant delay in mouse mortality. There were differences in the incidence, time to cerebral malaria and the level of parasitaemia when the drug combination was administered to mice. When used in combination with MQ, AVA had a relevant effect on the in vivo growth inhibition and clinical outcome of P. berghei ANKA-infected mice.

Systemic lupus erythematosus and cardiovascular disease: prediction and potential for therapeutic intervention

Patients with systemic lupus erythematosus have a significantly increased risk of cardiovascular events due to atherosclerosis. Traditional cardiac risk factors cannot fully explain this increased risk. Recent evidence strongly suggests that atherosclerotic plaque is largely driven by inflammation and an active immunological response, in contrast to the long-held belief that plaque is a passive accumulation of lipids in the arterial wall. Current approaches to the prevention of atherosclerosis in systemic lupus erythematosus involve targeting modifiable cardiac risk factors. Future preventive strategies may include therapies that counteract the immunologic responses that lead to plaque formation.

Effect of vitamin C and iron chelation on diesel exhaust particle and carbon black induced oxidative damage and cell adhesion molecule expression in human endothelial cells

Exposure to particulate matter is associated with oxidative stress and risk of cardiovascular diseases. We investigated if vitamin C and desferrioxamine (iron chelator) altered the levels of oxidative stress and expression of cell adhesion molecules upon exposure to diesel exhaust particles (DEP) and carbon black in cultured human umbilical vein endothelial cells (HUVECs). We found that the particles were only slightly cytotoxic in the high concentration ranges. Particle-induced intracellular reactive oxygen species (ROS) production was attenuated by vitamin C administration or iron chelation and particularly when combined (p<0.001). Only desferrioxamine protected the DNA from oxidative damage in terms of strand breaks and formamidopyrimidine DNA glycosylase sensitive sites induced by carbon black (p<0.01). Carbon black and small sized DEP generated from an Euro4 engine increased the surface expression of VCAM-1 and ICAM-1, whereas DEP from an engine representing an old combustion type engine (SRM2975) with larger particles did not affect the expression of cell adhesion molecules. These effects were also attenuated by desferrioxamine but not vitamin C. The study shows that exposure to carbon black and DEP in HUVECs can generate both oxidative stress and expression of cell surface adhesion molecules and that these effects can in part be attenuated by vitamin C and desferrioxamine.

Protein geranylgeranylation controls collagenase expression in osteoarthritic cartilage

OBJECTIVE

Statins possess anti-inflammatory properties. This study was undertaken to characterize the mechanism of action of statin drugs on collagenase expression in primary human osteoarthritic cartilage tissue.

METHOD

Human articular chondrocytes and cartilage explants from osteoarthritic donors were exposed to simvastatin in the presence or absence of interleukin-1 beta (IL-1beta). Collagenase expression was determined by quantifying levels of matrix metalloproteinase 13 (MMP-13) and MMP-1 mRNA and MMP-13 protein. The mechanism of statin action was tested by addition of farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP) or by using inhibitors of farnesyl transferase (FT) and geranylgeranyl transferase (GGT-1).

RESULTS

Treatment of osteoarthritic chondrocytes with simvastatin decreased mRNA levels of MMP-13 and MMP-1 whether under basal conditions or during stimulation with IL-1beta. MMP-13 protein secreted into the culture media was also decreased. Genes involved in cartilage synthesis (type II collagen and aggrecan) were not down-regulated by simvastatin. Exogenous addition of GGPP completely reversed the statin-mediated decrease in MMP-13 mRNA and protein levels whereas FPP partially reversed the statin-mediated effect. An inhibitor of GGT-1 mimicked the simvastatin-mediated reduction in MMP-13 expression by chondrocytes. Finally, consistent with impacts on MMP-13 and MMP-1 expression, simvastatin as well as the GGT-1 inhibitor both blocked type II collagen degradation in primary human articular cartilage explants.

CONCLUSION

These results suggest that statins modulate chondrocyte metabolism by reducing prenylation of key signaling molecules that control the expression of collagen-degrading enzymes. Our results strongly support the hypothesis that protein prenyltransferases including geranylgeranyl transferase regulate chondrocyte collagenase expression in osteoarthritis.

Pleiotropic effects of statins. - Basic research and clinical perspectives -

Statins are 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, which are widely used to lower serum cholesterol levels in the primary and secondary prevention of cardiovascular disease. Recent experimental and clinical evidence suggests that the beneficial effects of statins may extend beyond their cholesterol-lowering effects, to include so-called pleiotropic effects. These cholesterol-independent effects include improving endothelial function, attenuating vascular and myocardial remodeling, inhibiting vascular inflammation and oxidation, and stabilizing atherosclerotic plaques. The mechanism underlying some of these pleiotropic effects is the inhibition of isoprenoid synthesis by statins, which leads to the inhibition of intracellular signaling molecules Rho, Rac and Cdc42. In particular, inhibition of Rho and one of its downstream targets, Rho kinase, may be a predominant mechanism contributing to the pleiotropic effects of statins. The aim of the present review is to provide an update on the non-cholesterol-dependent statin effects in the cardiovascular system and highlight some of the recent findings from bench to bedside to support the concept of statin pleiotropy.

Statins and cardiovascular diseases: from cholesterol lowering to pleiotropy

Statins are 3-hydroxy-3-methyglutaryl coenzyme A (HMG-CoA) reductase inhibitors, which are prescribed extensively for cholesterol lowering in the primary and secondary prevention of cardiovascular disease. Recent compelling evidence suggests that the beneficial effects of statins may not only be due to their cholesterol lowering effects, but also, to their cholesterol-independent or pleiotropic effects. Through these so-called pleiotropic effects, statins are directly involved in restoring or improving endothelial function, attenuating vascular remodeling, inhibiting vascular inflammatory response, and perhaps, stabilizing atherosclerotic plaques. These cholesterol-independent effects of statins are predominantly due to their ability to inhibit isoprenoid synthesis, the products of which are important lipid attachments for intracellular signaling molecules, such as Rho, Rac and Cdc42. In particular, inhibition of Rho and its downstream target, Rho-associated coiled-coil containing protein kinase (ROCK), has emerged as the principle mechanisms underlying the pleiotropic effects of statins. This review provides an update of statin-mediated vascular effects beyond cholesterol lowering and highlights recent findings from bench to bedside to support the concept of statin pleiotropy.

HMG-CoA reductase inhibitors: do they have potential in the treatment of polycystic ovary syndrome?

Many women of reproductive age are affected by polycystic ovary syndrome (PCOS), a heterogeneous endocrinopathy characterized by androgen excess, chronic oligo-anovulation and/or polycystic ovarian morphology. In addition, PCOS is often associated with insulin resistance, systemic inflammation and oxidative stress, which, on one hand, lead to endothelial dysfunction and dyslipidaemia with subsequent cardiovascular sequelae and, on the other hand, to hyperplasia of the ovarian theca compartment with resultant hyperandrogenism and anovulation. Traditionally, HMG-CoA reductase inhibitors (statins) have been used to treat dyslipidaemia by blocking HMG-CoA reductase (the rate-limiting step in cholesterol biosynthesis); however, they also possess pleiotropic actions, resulting in antioxidant, anti-inflammatory and anti-proliferative effects. Statins offer a novel therapeutic approach to PCOS in that they address the dyslipidaemia associated with the syndrome, as well as hyperandrogenism or hyperandrogenaemia. These actions may be due to an inhibition of the effects of systemic inflammation and insulin resistance/hyperinsulinaemia. Evidence to date, both in vitro and in vivo, suggests that statins have potential in the treatment of PCOS; however, further clinical trials are needed before they can be considered a standard of care in the medical management of this common endocrinopathy.

Statins in the treatment of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy affecting reproductive-aged women. The hyperandrogenemia associated with the syndrome is a result of excessive growth and steroidogenic activity of theca-interstitial tissues in response to various factors, including elevated gonadotropins, hyperinsulinemia, and oxidative stress. PCOS frequently coexists with other cardiovascular risk factors, such as dyslipidemia and systemic inflammation. Statins inhibit the synthesis of mevalonate, the key precursor to cholesterol biosynthesis, and reduce cardiovascular morbidity and mortality. Blockade of mevalonate production may also lead to decreased maturation of insulin receptors, inhibition of steroidogenesis (e.g., via limiting the amount of substrate: cholesterol), and alteration of signal transduction pathways that mediate cellular proliferation. The latter depend upon posttranslational modification of proteins (prenylation), a process mediated by mevalonate derivatives. Statins also have intrinsic antioxidant properties. Given the pleiotropic actions of statins, they are likely not only to improve the dyslipidemia associated with PCOS but may also exert other beneficial metabolic and endocrine effects.

Reversal of chemoresistance and enhancement of apoptosis by statins through down-regulation of the NF-kappaB pathway

We recently found that simvastatin can modulate the nuclear factor-kappaB (NF-kappaB) activation pathway, but whether other statins have similar effects to those of simvastatin is unknown. Therefore, we evaluated the effect six different statins on TNF-induced NF-kappaB activation in human myeloid leukemia cells. We then determined whether the combination of statins and standard chemotherapeutic agents could overcome chemoresistance and augment apoptosis. Of the six statins evaluated, only the natural statins (simvastatin, mevastatin, lovastatin, and pravastatin), not the synthetic statins (fluvastatin and atorvastatin), inhibited TNF-induced NF-kappaB activation. Simvastatin suppressed the NF-kappaB activation and potentiated the apoptosis induced by doxorubicin, paclitaxel, and 5-fluorouracil. These results suggest that different statins behave differently from one another and that they may be useful in overcoming chemoresistance.

Statins and biomarkers of inflammation

Clinical and epidemiologic studies convincingly demonstrate that increased levels of low-density lipoprotein cholesterol promote premature atherosclerosis. Several large clinical trials have demonstrated that 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) decrease cardiovascular events. The beneficial effects of statins may extend to mechanisms beyond cholesterol reduction. Evidence for the pleiotropic effects of statins is provided by recent clinical trials in which the benefit of statin drugs is manifest early in the course of lipid-lowering therapy, well before plaque regression could occur. Inflammation is pivotal in all stages of atherosclerosis, and C-reactive protein (CRP), the prototypic marker of inflammation, has emerged as a cardiovascular risk marker. Statins reduce CRP levels, and this reduction in most studies does not correlate to reduction in cholesterol. In addition, statins have beneficial effects on endothelial function, monocyte-macrophages, and platelets. In this review we discuss the role of inflammation in atherosclerosis, the role of CRP as a risk marker, the clinical evidence implicating the anti-inflammatory effects of statins, and the cellular and molecular basis underlying the anti-inflammatory effects of statins.

High dosage of simvastatin reduces TNF-alpha-induced apoptosis of endothelial progenitor cells but fails to prevent apoptosis induced by IL-1beta in vitro

Endothelial progenitor cells (EPC) could provide a possible source for the improvement of neovascularization in injured tissues following multiple trauma. Recently, it became obvious that at least two types of EPC can be cultured from peripheral blood mononuclear cells. In this work we focused on the fraction of the easily accessible early EPC, which can be generated in clinically relevant amounts within 5 days. Periods of hyper-inflammation, systemic or local, often occur during a multiple trauma. Thus, this study was conducted to elucidate the influence of the prototypical proinflammatory cytokines interleukin (IL)-1beta and tumor necrosis factor-alpha (TNF-alpha) on the survival of early EPC. In the past years it was observed that HMG-CoA reductase inhibitors (statins) exert protective effects during inflammatory processes. Therefore, the effect of a preconditioning of early EPC with simvastatin on the survival of EPC under proinflammatory conditions was tested as well. Incubation with 50 mu/mL TNF-alpha [0.45 ng/mL] or IL-1beta [0.25 ng/mL] resulted in a 3-fold (18.4 +/- 2.9%), respectively, 4-fold (25.5 +/- 3.4%) increase of apoptotic EPC in comparison to the untreated control (6.1 +/- 1.6%). In accordance, 24 h after the cytokines had been added, the EPC number per high power field decreased significantly. A preconditioning with simvastatin [25 microM] resulted in significant inhibition of the TNF-alpha-induced apoptosis, whereas the IL-1beta-mediated apoptosis was only slightly reduced. In conclusion, this study shows clearly that TNF-alpha and IL-1beta are harmful to early EPC and that the HMG-CoA reductase inhibitor simvastatin protects EPC from TNF-alpha- and eventually from IL-1beta-mediated apoptosis. These results suggest that simvastatin has protective effects on EPC survival and differentiation in a hyperinflammatory situation.

The effect of HMG-CoA reductase inhibitors on naturally occurring CD4+CD25+ T cells

Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) are in widespread use due to their LDL reducing properties and concomitant improvement of clinical outcome in patients with and without preexisting atherosclerosis. Considerable evidence suggests that immune mediated mechanisms play a dominant role in the beneficial effects of statins. Naturally occurring CD4(+)CD25(+) regulatory T cells (Tregs) have a key role in the prevention of various inflammatory and autoimmune disorders by suppressing immune responses. We tested the hypothesis that statins influence the circulating number and the functional properties of Tregs. We studied the effects of in vivo and in vitro statin treatment of human and murine mononuclear cells on the number of Tregs and the expression level of their master transcription regulator, Foxp3. Atorvastatin, but not mevastatin nor pravastatin, treatment of human peripheral blood mononuclear cells (PBMCs) increased the number of CD4(+)CD25(high) cells, and CD4(+)CD25(+)Foxp3(+) cells. These Tregs, induced by atorvastatin, expressed high levels of Foxp3, which correlated with an increased regulatory potential. Furthermore, co-culture studies revealed that atorvastatin induced CD4(+)CD25(+)Foxp3(+) Tregs were derived from peripheral CD4(+)CD25(-)Foxp3(-) cells. Simvastatin and pravastatin treatment in hyperlipidemic subjects increased the number of Tregs. In C57BL/6 mice however, no effect of statins on Tregs was evident. In conclusion, statins appear to significantly influence the peripheral pool of Tregs in humans. This finding may shed light on the mechanisms governing the plaque stabilizing properties of statins.

Effectiveness of statins in reducing the rate of severe sepsis: a retrospective evaluation

STUDY OBJECTIVES

To determine whether use of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) is associated with a reduced rate of severe sepsis, and to further characterize the effect of statins on the frequency of organ dysfunction in patients with severe sepsis.

DESIGN

Retrospective cohort study.

SETTING

University-associated teaching hospital.

PATIENTS

Fifty-three patients admitted with sepsis; 16 were receiving statins and 37 were not receiving statins (controls) before admission.

MEASUREMENTS AND MAIN RESULTS

Patients were identified by the International Classification of Diseases, Ninth Revision, Clinical Modification codes. Patient demographics, vital signs, and laboratory values were collected from their electronic medical records. The primary end point was rate of severe sepsis, defined in accordance with guidelines from the American College of Chest Physicians and the Society of Critical Care Medicine. Secondary end points were in-hospital mortality rate and rate of five categories of organ dysfunction (cardiovascular, renal, pulmonary, hematologic, and metabolic). Preadmission statin therapy, compared with no statin therapy, was associated with a 30% lower rate of severe sepsis (56% vs 86%, p<0.02). In-hospital mortality was not significantly different between groups (38% vs 49%, p=0.33); however, the rate of cardiovascular dysfunction, defined as hypotension requiring vasopressor therapy, was significantly lower in the statin group (38% vs 73%, p<0.02). No significant differences in the other organ dysfunction categories were noted between groups.

CONCLUSION

Statins appear to prevent sepsis from becoming severe, most notably through prevention of sepsis-induced hypotension. This potential role for statins in the prevention and treatment of severe sepsis should be further evaluated in a randomized controlled trial.

Statins and the vascular endothelial inflammatory response

Statins reduce cholesterol synthesis and are widely used for the treatment of hyperlipidaemia and ischaemic heart disease. Besides their cholesterol-lowering effects, statins also possess broad immunomodulatory and anti-inflammatory properties. Vascular endothelial cells have a crucial role in the pathogenesis of inflammatory disease, and, alongside leukocytes and antigen-presenting cells, represent a key cellular target for statin therapy. Recent studies investigating how these drugs modify endothelial cell function demonstrate that the therapeutic effect of statins can be attributed, in part, to their action on the endothelium. Accordingly, statins attenuate endothelial MHC class II expression, increase endothelial nitric oxide synthase and fibrinolytic activity, decrease leukocyte adhesion and transmigration, and enhance resistance to local injurious stimuli. Many of these effects are brought about by the modulation of small GTPase function and the downregulation of proinflammatory gene expression.

Simvastatin inhibits the migration and adhesion of monocytic cells and disorganizes the cytoskeleton of activated endothelial cells

Statins are powerful agents for lowering plasma cholesterol levels, which act by inhibition of the 3-hydroxy-3-methylglutaryl-CoA reductase. Evidence suggests that some of the beneficial effects may depend on their anti-inflammatory properties, due to their ability to suppress the synthesis of isoprenoids. The present study analyzes the effects of short-term simvastatin exposure on monocyte migration, cell adhesion, and endothelial cytoskeleton. We demonstrate that simvastatin completely inhibited the migration of THP-1 monocytic cells after 24 h of incubation, being prevented by coincubation with mevalonate (MVA) and geranylgeranylpyrophosphate (GGPP), but not by farnesylpyrophosphate (FPP). Simvastatin decreased chemotaxis to 70% after one hour of incubation; surprisingly neither MVA, GGPP nor FPP were able to restore the effects of the drug. Simvastatin also significantly reduced the adhesion of monocytes to interleukin-1beta (IL-1beta)-activated endothelium to 80% after preincubation for 24 h. This effect was completely reversed by coincubation with MVA and GGPP, and partially with FPP. Unexpectedly, simvastatin increased adhesion molecules expression VCAM-1 and ICAM-1 on cytokine-stimulated endothelial cells. Examination of the actin cytoskeleton on IL-1beta-activated endothelial cells showed that both 4 and 24 h of incubation with simvastatin produced a complete disappearance of F-actin, being completely restored by MVA and partially by GGPP and FPP after 24 h of coincubation. We suggest that cytoskeleton disorganization in endothelial cells is important for inhibiting monocyte adhesion, altering the adhesion molecules function. Taken together, these results strongly support the beneficial anti-inflammatory properties of statins, contributing to the overall clinical effects.

Statins and the endothelium

Statins have been shown to have pleiotropic effects apart from serum lipid-lowering effect in human. One of the major target organs for the effects of statins is the vascular endothelium, which plays an important role in the development of atherosclerosis and angiogenesis. Recent numerous studies have shown that the statins' cholesterol-independent vascular effects appear to involve directly restoring or improving endothelial function by increasing NO production, promoting re-endothelialization after arterial injury, and inhibiting inflammatory responses within the vessel wall that are thought to contribute to atherosclerosis. This review provides an update of the unique effects of statins on endothelial cells including endothelial progenitor cells as well as highlighting the therapeutic potential of statins beyond their established lipid-lowering effects.

Simvastatin inhibits cigarette smoking-induced emphysema and pulmonary hypertension in rat lungs

RATIONALE

In cigarette smoking-induced chronic obstructive pulmonary disease, structural and functional derangements are characterized by parenchymal destruction and pulmonary hypertension. Statins are 3-hydroxy-3-methyl-glutaryl-coenzyme-A reductase inhibitors that have been used as lipid-lowering agents. These drugs also have additional pharmacologic properties, including antiinflammation, scavenging reactive oxygen species, restoring endothelial function, and antithrombogenesis, all of which can counteract the harmful effects of cigarette smoking.

OBJECTIVE

We performed assays to determine whether simvastatin could attenuate lung damage induced by chronic cigarette smoking in rats.

METHODS

In Sprague-Dawley rats exposed to cigarette smoke for 16 weeks, morphologic changes in the lungs and pulmonary arterial pressure were examined.

MAIN RESULTS

Simvastatin inhibited lung parenchymal destruction and development of pulmonary hypertension, and also inhibited peribronchial and perivascular infiltration of inflammatory cells and induction of matrix metalloproteinase-9 activity in lung tissue. Simvastatin additionally prevented pulmonary vascular remodeling and the changes in endothelial nitric oxide synthase expression induced by smoking. In human lung microvascular endothelial cells, simvastatin increased expression of endothelial nitric oxide synthase mRNA.

CONCLUSIONS

Simvastatin ameliorated the structural and functional derangements of the lungs caused by cigarette smoking, partly by suppressing inflammation and matrix metalloproteinase-9 induction and preventing pulmonary vascular abnormality. These findings indicate that statins may play a role in the treatment of cigarette smoking-induced chronic obstructive pulmonary disease.

Inhibition of phosphoinositide 3 kinase-Akt (protein kinase B)-nuclear factor-kappaB pathway by lovastatin limits endothelial-monocyte cell interaction

Integrity of the blood-brain barrier is essential for the normal functioning of CNS. Its disruption contributes to the pathobiology of various inflammatory neurodegenerative disorders. We have shown that the HMG-CoA reductase inhibitor (lovastatin) attenuated experimental autoimmune encephalomyelitis (EAE, an inflammatory disease of CNS) in rodents by inhibiting the infiltration of mononuclear cells into the CNS. Here, using an in vitro system, we report that lovastatin inhibits endothelial-monocyte cell interaction by down-regulating the expression of vascular cell adhesion molecule-1 and E-selectin by inhibiting the phosphoinositide 3 kinase (PI3-kinase)/protein kinase B (Akt)/nuclear factor-kappa B (NF-kappaB) pathway in endothelial cells. It inhibits tumor necrosis factor alpha (TNFalpha)-induced PI3-kinase, Akt and NF-kappaB activation in these cells. Co-transfection of constitutively active forms of PI3-kinase and Akt reversed the lovastatin-mediated inhibition of TNFalpha-induced adhesion, as well as activation of NF-kappaB, indicating the involvement of the PI3-kinase/Akt pathway in the interaction of adhesion molecules and the process of adhesion. This study reports that lovastatin down-regulates the pathway affecting the expression and interaction of adhesion molecules on endothelial cells, which in turn restricts the migration and infiltration of mononuclear cells thereby attenuating the pathogenesis of inflammatory diseases.

Utility of statin therapy using high-sensitivity C-reactive protein as an indicator of coronary heart disease risk

High-sensitivity C-reactive protein (CRP), a nonspecific marker of inflammation, is a newly available biomarker for predicting the risk of cardiovascular events. CRP has been shown to predict risk of cardiovascular events independent of traditional risk factors and in the setting of low levels of low-density lipoprotein cholesterol. Statins have been shown to decrease CRP, and studies are now under way to evaluate if targeting patients with high CRP and low low-density lipoprotein cholesterol will have any impact on future cardiovascular events and survival and whether changes in CRP correlate to event reduction. The utility of CRP as a target of therapy remains to be proved, and these ongoing studies will likely provide us with guidance.

Simvastatin blunts the increase of circulating adhesion molecules after coronary artery bypass surgery with cardiopulmonary bypass

OBJECTIVES

Endothelial dysfunction has been shown to be a critical early component of organ injury after myocardial ischemia and reperfusion. Circulating levels of adhesion molecules have been regarded as a valid index of endothelial activation. Recent reports suggest that statins, widely used in the control of hypercholesterolemia, exert a protective effect on the endothelium reflected by a reduced level of circulating adhesion molecules. In this study, the effects of preoperative simvastatin treatment, at doses equivalent to those used orally for cholesterol control, were studied on plasma levels of VCAM-1, ICAM-1, and ELAM-1.

DESIGN

A case-control study.

SETTING

University hospital.

PARTICIPANTS

Fifteen patients taking simvastatin with good control of cholesterol levels, 15 patients not responsive to the simvastatin treatment, and 15 normocholesterolemic patients (control) undergoing elective coronary artery bypass surgery.

MEASUREMENTS AND MAIN RESULTS

The plasma levels of VACM-1, ICAM-1, and ELAM-1 were evaluated at baseline; during cardiopulmonary bypass; and 6 hours, 24 hours, and 48 hours postoperatively. In the late postoperative samples, the plasma levels of ICAM-1 and ELAM-1 were lower in both simvastatin-treated patients compared with the control patients. No significant difference was found between the patients responsive to statin and those not responsive. Finally, no significant difference was found for VCAM-1 plasma levels between the control group and the 2 treatment groups.

CONCLUSIONS

Pretreatment with simvastatin significantly reduces the increase of ICAM-1 and ELAM-1 after coronary artery bypass surgery, by a mechanism that seems not related to its efficacy in lowering cholesterol levels.

Growth hormone receptor expression and function in pituitary adenomas

OBJECTIVE AND DESIGN

Hypopituitarism, in particular GH deficiency, is prevalent in patients with clinically nonfunctioning pituitary adenomas (NFPAs) both before and after surgery. The factors regulating the growth of pituitary adenomas in general and residual tumour tissue in particular are not fully characterized, and the effect of GH and IGF-I on human pituitary cell proliferation has not previously been reported. In NFPA tissue from 14 patients we evaluated GH receptor (GHR) expression and signal transduction, and the effect of GH and IGF-I exposure on cell proliferation and hormone secretion in vitro.

MEASUREMENTS

Tissue samples from 14 NFPAs were investigated. Expression of GHR in tissue samples was assessed by reverse transcription polymerase chain reaction (RT-PCR). Six tumours were immunostained with a GHR antibody. In the cell cultures, STAT5 (signal transducer and activator of transcription 5) phosphorylation was measured by Western blot analysis as an index of GHR signalling; cell proliferation was evaluated by [H3]-thymidine incorporation and glycoprotein hormone production analysed by radioimmunoassay (RIA).

RESULTS

All adenomas investigated expressed the GHR, but there was no detection of STAT5 phosphorylation. Overall, GH and IGF-I administration did not significantly stimulate cell proliferation in vitro, although some individual adenomas exhibited a proliferative response to various extents. GH also did not significantly influence glycoprotein hormone secretion in vitro.

CONCLUSION

GH receptors are expressed in human pituitary adenoma cells but their functional role is uncertain. GH and IGF-I do not consistently influence the proliferation of cultured pituitary adenoma cells.

Cellular adhesion molecules and cardiovascular disease. Part II. Their association with conventional and emerging risk factors, acute coronary events and cardiovascular risk prediction

The role of cellular adhesion molecules in the patho-genesis of atherosclerosis has now been clearly demonstrated. Plasma levels of adhesion molecules, which have been shed from the cell surface, have also been associated with the presence of clinical atherosclerotic disease, cardiovascular risk factors and acute coronary syndromes. However, there is little consensus in the literature, including between the large well-designed population studies. This may be explained either by unrecognized confounding factors or, alternatively, by the unpredictable relationship between cell surface expression and activity of cellular adhesion molecules and their shedding into the plasma under different circumstances. Probably for the latter reasons, there is at present little evidence that the measurement of circulating adhesion molecules is likely to offer any additional benefit for individual patients above the assessment of conventional cardiovascular risk factors in the assessment of either the extent of, or future risk from, cardiovascular disease.

Effects of statins on adhesion molecule expression in endothelial cells

BACKGROUND

Inhibitors of HMG-CoA reductase are widely used to prevent atherosclerosis progression. The expression of adhesion molecules on activated endothelial cells (EC) is an important step in the initiation and progression of atherosclerosis.

OBJECTIVES

We investigated whether adhesion molecule expression on activated EC is influenced by simvastatin, fluvastatin and pravastatin and, if so, by which mechanisms.

METHODS

Human EC from umbilical veins or saphenous veins were pretreated overnight with statins with or without mevalonate, and also for simvastatin or fluvastatin with the isoprenoid intermediates, farnesyl pyrophosphate (FPP), or geranylgeranyl pyrophosphate (GGPP). After 4-6 h activation with tumor necrosis factor (TNF)-alpha or lipopolysaccharide (LPS), surface adhesion molecule expression was evaluated by ELISA and by flow cytometry. The same experiments were performed with selective inhibitors of geranylgeranyltransferase (GGTI-286) and farnesyltransferase (FTI-277).

RESULTS

Pretreatment with simvastatin, fluvastatin or pravastatin potentiated the TNF-alpha and LPS-induced expression of E-selectin and VCAM-1, and mevalonate reversed the potentiating effect of these statins. GGPP also reversed the potentiating effect of simvastatin or fluvastatin on adhesion molecule expression, while FPP only partially reversed this effect. Furthermore, GGTI-286, but not FTI-277, mimicked the effect of simvastatin by increasing the TNF-alpha-mediated overexpression of E-selectin.

CONCLUSIONS

Statins increase E-selectin- and VCAM-1-induced expression on vascular endothelial cells stimulated with TNF-alpha or LPS. The inhibition of geranylgeranylated proteins could contribute to this effect.

Effect of atorvastatin on adhesive phenotype of human endothelial cells activated by tumor necrosis factor alpha

We studied the effect of atorvastatin on the adhesive phenotype of human endothelial cells (HUVEC) stimulated by tumor necrosis factor (TNF)-alpha. Surface expression of adhesion molecules on HUVEC was examined by flow cytometry and confocal microscopy, and adhesion of monocytes (human THP-1 cell line) was measured in vitro under flow conditions. In TNF-alpha-activated HUVEC, atorvastatin significantly enhanced surface expression of vascular cell adhesion molecule (VCAM)-1, intercellular adhesion molecule (ICAM)-1, E-selectin, and fractalkine, when compared with TNF-alpha stimulation alone. This enhancement was reversed by mevalonate or geranylgeranyl pyrophosphate (GGPP) and was mimicked by an inhibitor of geranylgeranylation. The enhancing effect of atorvastatin was restricted to TNF-alpha-inducible adhesion molecule and was the reflect of an increased protein synthesis (mRNA and protein) and not of a reduced shedding. Confocal microscopy examination showed that atorvastatin also altered the surface distribution of adhesion molecules. Adhesion of human THP-1 cells on TNF-alpha-activated HUVEC was significantly reduced by atorvastatin (-42% at 1 microM). Mevalonate or GGPP restored the TNF-alpha-induced adhesive potential. These results show that atorvastatin, by inhibiting prenylation of G proteins, enhances the TNF-alpha-induced expression of adhesion molecules at the endothelial cell surface and also alters their surface distribution which may account for the reduced binding of monocytes.

Pravastatin promotes coronary collateral circulation in patients with coronary artery disease

BACKGROUND

Previous studies suggested that hydroxymethylglutaryl coenzyme A reductase inhibitor (statin) promotes collateral circulation in ischemic limbs of rabbits. The present study was designed to determine the association between treatment with pravastatin and the development of coronary collateral circulation as assessed by the Rentrop Score in patients with coronary artery disease (CAD) in a case-control study.

DESIGN

The study included patients who had one (1-V), two (2-V) or three (3-V) significantly stenosed vessels. Patients who did and did not receive pravastatin were defined as case participants (n = 42) and control participants (n = 100), respectively.

RESULTS

The case participants included a higher percentage of 3-V patients with a Rentrop Score 1 compared to the control participants but there was no difference among 1-V and 2-V patients, suggesting that pravastatin was associated with coronary collateral circulation independent of the number of stenosed vessels. Patients with 3-V disease who were treated with pravastatin were most likely [odds ratio (confidence interval), 17.4 (4.4-115)] to develop collateral circulation, as assessed by multiple logistic regression analysis.

CONCLUSIONS

Treatment with pravastatin was associated with the development of collateral circulation in patients with CAD, suggesting that such action constitutes part of the pleiotropic effects of statin.