OP0338 MASS SPECTROMETRY IDENTIFIES NOVEL BIOMARKERS IN GIANT CELL ARTERITIS, USEFUL IN PATIENTS ON INTERLEUKIN-6 RECEPTOR BLOCKADE

Background:

Acute phase reactants (erythrosedimentation rate [ESR], C-reactive protein [CRP]) have limited utility in GCA, even in patients treated with prednisone alone. Furthermore, the lack of reliable biomarkers in patients receiving interleukin (IL)-6 blockade therapy is a major unmet need.

Objectives:

To identify biomarkers of disease activity in GCA patients treated with prednisone monotherapy and with prednisone in combination with tocilizumab (TCZ).

Methods:

We mapped the serum proteome of GCA patients with active and inactive disease in an unbiased manner using high-throughput multiplexed mass spectrometry. Proteomic analyses were performed in 5 µl serum samples with 11-plexed tandem mass tag (TMT) technology using an Orbitrap Lumos mass spectrometer. A SEQUEST-based database search engine was employed for peptide identification. Quantification was based on TMT reporter ion intensities. All patients were sampled during their participation in the GiACTA trial,1in which they received TCZ plus 26 weeks of prednisone (TCZ group) or placebo plus 26 or 52 weeks of prednisone (PRED group). Active disease was defined as the presence of cranial or PMR symptoms requiring treatment intensification regardless of ESR and CRP levels. Samples were selected if patients were in clear states of active or inactive disease at GiACTA systematic sample collection timepoints (baseline and weeks 4, 12, 24, 48). An exhaustive leave-2-out strategy was used to identify classification markers. All possible pairs of samples were isolated as test samples and the remaining training samples were used to identify the protein markers. Proteins with an absolute log2 fold concentration difference ≥0.5 between active and inactive samples and a P-value <0.1 were retained and sorted based on the metric -log10(P-value)*absolute(log2 fold change). Top markers within each training set were selected to generate normalized ranks {0,1} across all samples. A mean rank was calculated for every sample. The set of normalized ranks for the test samples across all sets of top markers were bootstrapped for each test sample 100 times with replacement. The bootstrapped rankings were evaluated by determining areas under the curves (AUC) of receiver operator characteristic (ROC) curves.

Results:

The PRED group included 21 patients (active, n = 16; inactive, n = 5) and the TCZ group included 21 patients (active, n = 14; inactive, n = 7). Using high-throughput sample preparation methods without applying any depletion of known highly abundant serum proteins, we quantified 760 proteins across all samples and 344 proteins in at least half the samples. Compared to inactive PRED-treated patients, active PRED-treated patients showed significant overexpression of several acute phase reactants including serum amyloid A1 and 2 (SAA1, SAA2) and complement factor H (CFH) (Fig. 1a). The magnitude of concentration change and the level of statistical significance observed for SSA1, SSA2 and CFH in PRED-treated patients were higher than those of CRP (Fig. 1a). Compared to inactive TCZ-treated patients, active TCZ-treated patients demonstrated significant overexpression of multiple biomarkers including haptoglobin, haptoglobin precursor, SSA2 and complement factor 4A, and underexpression of peptidase inhibitor 16 (Fig. 1b), a protein involved in vascular and regulatory T cell biology. Sets of 10 biomarkers resulted in a classification of active versus inactive disease with ROC AUCs of 0.89 (95% CI 0.79-0.96) in the PRED group (Fig. 2a) and 0.97 (95% CI 0.95-0.97) in the TCZ group (Fig. 2b).

Conclusion:

We identified several differentially expressed serum proteins in GCA patients with active and inactive disease receiving prednisone monotherapy or TCZ-based treatment regimens. In both treatment groups, a signature of biomarkers classified disease activity status with high accuracy. Haptoglobin, a readily available laboratory test, may be useful in monitoring disease activity in GCA patients receiving IL-6 blockade therapy.

References:

[1]Stoneet al.NEJM2017

Disclosure of Interests:

Sebastian Unizony Grant/research support from: Genentech, Inc., Robert Morris: None declared, Johannes Kreuzer: None declared, Wilhelm Haas: None declared, John H. Stone Grant/research support from: Roche, Consultant of: Roche

Current management of upper gastrointestinal bleeding

Despite the introduction of proton pump inhibitors and modern flexible endoscopy techniques, upper gastrointestinal bleeding is still a common and serious condition. Once considered the domain of surgery, it is now uncommon to treat endoscopically controllable bleeding surgically. Therefore, most surgically treated cases are complicated and associated with a high mortality rate. This article presents the current management of upper gastrointestinal bleeding. Besides the description of current endoscopic treatment, medical prophylaxis and treatment, as well as radiological intervention, the article describes the indication and the surgical procedure.

Update on anti-coagulation in atrial fibrillation

Atrial fibrillation (AF), the most common clinically relevant arrhythmia, affects 2.2 million individuals in the USA and 4.5 million in Europe, resulting in significant morbidity and mortality. Pharmacotherapy aimed at controlling both heart rate and rhythm is employed to relieve AF symptoms, though debate continues about which approach is preferable. AF prevalence rises with age from 0.4% to 1% in the general population to 11% in those aged >70 years. AF is associated with a pro-thrombotic state and other comorbidities; age, hypertension, heart failure and diabetes mellitus all play a key role in AF pathogenesis. Anti-coagulation is essential for stroke prevention in patients with AF and is recommended for patients with one or more risk factors for stroke. Used within the recommended therapeutic range, warfarin and other vitamin K antagonists decrease the incidence of stroke and mortality in AF patients. Warfarin remains under-used, however, because of the perceived high risk of haemorrhage, narrow therapeutic window and need for regular monitoring. Several novel anti-coagulants show promise in AF-related stroke prevention. In particular, the novel, oral, direct thrombin inhibitor, dabigatran etexilate, recently licensed by the US Food and Drug Administration (FDA) and Health Canada has shown improved efficacy and safety compared with warfarin for stroke prevention in AF, and has the potential to replace warfarin in this indication. The increasing number of new therapeutic options, including improved anti-arrhythmic agents, novel anti-coagulants and more accessible ablation techniques, are likely to deliver better care for AF patients in the near future.

Clopidogrel versus aspirin in patients with atherothrombosis: CAPRIE-based calculation of cost-effectiveness for Germany

OBJECTIVES

To model the 2-year cost-effectiveness of secondary prevention with clopidogrel versus aspirin (acetylsalicylic acid) (ASS) in German patients with myocardial infarction (MI), ischaemic stroke (IS) or diagnosed with peripheral arterial disease (PAD), based on CAPRIE trial data and from the perspective of German third party payers (TPP).

METHODS

An existing Markov model was adapted to Germany by using German cost data. The model was extended by using different datasets for cardiovascular event survival times (Framingham vs. Saskatchewan health databases) and in two separate scenarios.

RESULTS

The treatment with clopidogrel leads to a reduction of 13.19 vascular events per 1000 patients, of which 2.21 are vascular deaths. The overall incremental costs for the 2-year management of atherothrombotic patients with clopidogrel instead of ASS are calculated to be about euro1 241 440 per 1000 patients. The number of life-years saved (LYS) has been calculated as the difference in the number of life-years lost due to vascular death or events with ASS versus clopidogrel: it is 86.35 LYS when analysis is based on Framingham data and 66.07 LYS with Saskatchewan-based survival data. The incremental costs per LYS are euro14 380 and euro18 790, respectively. Cost-effectiveness is sensitive to changes in survival data, discounting and daily costs of clopidogrel, but stable against substantial (+/- 25%) changes in all other cost data.

CONCLUSION

The findings for Germany are in line with published results for Belgium (euro13 390 per LYS) and also with results for Italy (euro17 500 per LYS), both based on Saskatchewan data, and with a French analysis based on Framingham data (euro15 907 per LYS). Even if no officially accepted cost-effectiveness threshold exists for Germany at present, incremental cost-effectiveness results of less than euro20 000 per LYS for the treatment with clopidogrel can be assumed to be acceptable for German third party payers.

Influence of the angiotensin converting enzyme inhibitor ramipril on high-sensitivity C-reactive protein (hs-CRP) in patients with documented atherosclerosis

Some medications have been shown to produce reductions in hs-CRP levels after initiating therapy. Whereas the role of the renin-angiotensin system in the inflammatory process has been documented in more detail during the last few years, the impact of an ACE-inhibitor therapy on this process has not been fully understood so far. The aim of this study was to investigate the effect of a therapy with the angiotensin-converting enzyme (ACE) inhibitor ramipril on hs-CRP plasma concentrations in patients with atherosclerosis.

METHODS AND RESULTS

A total of 24 patients were enrolled in this prospective, uncontrolled, open-label multicenter study. Inclusion criteria were documented atherosclerosis, baseline high-sensitivity C-reactive protein between 3 and 12 mg/l, LDL-Cholesterol < or =150 mg/dl and no previous treatment with ACE inhibitors or angiotensin receptor blockers. Ten patients, pretreated with statins, and 10 patients not previously treated with statins were eligible for statistical analysis. Baseline high-sensitivity C-reactive protein was significantly decreased from 3.99+/-1.61 mg/l (mean+/-SD) to 2.72+/-1.19 mg/l (-32%) after 3 months treatment with 10 mg ramipril daily (p=0.0002). The decrease was more pronounced in patients who had not been treated with statins previously (-1.50 mg/l+/-1.44 mg/l) compared to those who were pretreated (-0.90 mg/l+/-0.93 mg/l).

CONCLUSIONS

The ACE inhibitor ramipril administered in a daily dose of 10 mg to patients with atherosclerosis reduces the high-sensitivity C-reactive protein concentration. This effect may contribute to cardiovascular risk reduction mediated by ramipril aside from the blood pressure lowering effect.

Nitric oxide-mediated endothelial dysfunction--is there need to treat?

Before it gets to the development of manifest atherosclerotic lesions, all known risk factors primarily induce functional alterations in the vascular wall, namely in endothelial cells. Being termed endothelial dysfunction or endothelial activation, this condition is characterized by an altered availability of nitric oxide (NO). Under physiological conditions, NO is of unequivocal importance for the regulation of vascular homeostasis. Endothelium-derived NO released abluminally increases soluble guanylat cyclase activity in smooth muscle cells, thereby inducing relaxation and consequently vasodilatation. Intraluminally, NO inhibits the expression of adhesion molecules both on endothielial cells and neutrophils, thus preventing the adherence of cellular elements to the vascular wall. Furthermore, NO has antithrombotic effcts by inhibiting platelet aggregation and directly infuencing the synthesis of different factors involved in the coagulation cascade. Finally, in the long term, NO has been shown to exert antiproliferative properties. NO is generated intracellularly from L-arginine via NO-synthase with the help of several cofactors, including tetrahydobiopterin. Interestingly, it has recently become evident that under certain conditions, when there is a lack of tetrahydrobiopterin, NO-synthase produces reactive oxygen species instead of NO. Reactive oxygen species counteract the effects of NO and also scavenge NO resulting in the formation of peroxynitrite (ONOO). Peroxynitrite has been shown to have deleterious effects with respect to vascular function. The aim of the current review is to elucidate recent progress regarding the pathophysiological understanding of endothelial dysfunction. Furthermore, the significance of this condition for the evaluation and prognosis of patients is discussed. Finally, current therapeutical strategies in the treatment and improvement of endothelial dysfunction are highlighted.

Ligand-dependent autophosphorylation of the insulin receptor is positively regulated by Gi-proteins

Previously, we have shown that the human insulin receptor (IR) interacts with G(i)2, independent of tyrosine kinase activity and stimulates NADPH oxidase via the Galpha subunit of G(i)2. We have now investigated the regulatory role of G(i)2-proteins in IR function. For the experiments, isolated IRs from plasma membranes of human fat cells were used. The activation of IR autophosphorylation by insulin was blocked by G-protein inactivation through GDPbetaS (guanosine 5'-[beta-thio]disphosphate). Consistently, activation of G-proteins by micromolar concentrations of GTPgammaS (guanosine 5'-[gamma-thio]triphosphate) induced receptor autophosphorylation 5-fold over baseline and increased insulin-induced autophosphorylation by 3-fold. In the presence of 10 microM GTPgammaS, insulin was active at picomolar concentrations, indicating that insulin acted via its cognate receptor. Pretreatment of the plasma membranes with pertussis toxin prevented insulin- and GTPgammaS-induced autophosphorylation, but did not disrupt the IR-G(i)2 complex. The functional nature of the IR-G(i)2 complex was made evident by insulin's ability to increase association of G(i)2 with the IR. This leads to an augmentation of maximal receptor autophosphorylation induced by insulin and GTPgammaS. The specificity of this mechanism was further demonstrated by the use of isolated preactivated G-proteins. Addition of G(i)2alpha and Gbetagamma mimicked maximal response of insulin, whereas Galphas or Galphao had no stimulatory effect. These results define a novel mechanism by which insulin signalling mediates tyrosine kinase activity and autophosphorylation of the IR through recruitment of G(i)-proteins.

Lipid-lowering therapy and cholesterol levels following acute myocardial infarction: a German study of 5361 patients

BACKGROUND

Current studies on secondary prevention of cardiovascular events (CARE, LIPID, 4S) illustrate the necessity of an effective lipid-lowering therapy. An important part of secondary prevention is the prompt measurement of lipids following an infarct, to be able to start therapy as quickly as possible.

AIMS

This study should show the general situation in the prescription of lipid-lowering drugs in patients with acute myocardial infarction (MI) and if there are gender differences in therapy and in the lipid parameters. The second aim was to determine the therapeutical conclusions for secondary prevention made in-hospital in patients with heart attacks.

METHODS

Post-infarct lipid parameters (total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), triglycerides (TG) were examined in 5361 patients within 24 hours following an acute MI. Lipid parameters from 576 patients were measured again after 1 week.

RESULTS

80.1% of men under examination and 81.9% of the women had suffered from their first MI. Only 9% of all patients were already under lipid-lowering therapy before the MI. After the MI TC and LDL-C levels decreased significantly in a time-dependent manner. Around 50% of patients received lipid-lowering drug, or the recommendation of one, during their hospital stay.

CONCLUSION

The range of TC values of the patients examined was comparable to those in the CARE and the 4S secondary prevention studies. It can therefore be assumed that the results of these studies are also applicable to Germany. Nevertheless, according to existing data, therapy with lipid-lowering drugs is currently unsatisfactory, even in secondary prevention.

Platelet-derived growth factor activates production of reactive oxygen species by NAD(P)H oxidase in smooth muscle cells through Gi1,2

Recent findings indicate that platelet-derived growth factor (PDGF) plays a role in the generation of reactive oxygen species (ROS) as second messengers in smooth muscle cells (SMC). To identify the source and signal transduction pathway of ROS formation in SMC, we investigated PDGF-induced ROS formation. Stimulation of SMC with PDGF resulted in a rapid increase of ROS production. Using an inactivating antibody, we identified the increase to be dependent on p22phox, a NAD(P)H-oxidase subunit. ROS release was completely inhibited by the Gi protein inhibitor PTX as well as an antibody against Galphai1,2, however, not by antibodies against Galphai3/0, Gas, and Gbeta1beta2. The effect of PDGF on ROS production in SMC membranes could likewise be mimicked by the use of a recombinant Galphai2 subunit but not by Galphai3, Galphai0, Gas, and Gbetagamma subunits. Immunoaffinity chromatography demonstrated coupling of Galphai1,2 to the PDGF a-receptor, which, after preincubation of the SMC membranes with PDGF, was increased in the absence of GTPgammaS but decreased in the presence of GTPgammaS and prevented by PTX treatment. These data define a novel G protein-dependent mechanism by which PDGF signaling is transduced through direct coupling of the Gai1,2 subunit of the trimeric G proteins to the PDGF tyrosine kinase receptor.

Fibrinogen induces chemotactic activity in endothelial cells

Chemotaxis of blood monocytes into the vessel wall together with the change of the relative content of the extracellular matrix (ECM) proteins at sites of predilection is an early cellular marker of atherogenesis. To examine the influence of ECM proteins on secretion of chemoattractants by endothelial cells (EC), porcine EC were seeded on gelatin (G), fibronectin (Fn) and fibrinogen (Fg). After 24 h cells seeded on G and Fn showed the histiotypic 'cobblestone'-morphology whereas cells seeded on Fg did not. Chemotactic activity for monocytes in supernatants from cells seeded on Fg was more than two-fold higher compared with G and was independent of soluble Fn or Fg in the supernatant. Quantification of monocyte chemoattracting protein-1, PDGF-AB and IL-8 in EC supernatants showed that Fg led to a significant increase in secretion of all three proteins compared with cells cultured on G. Preincubation of porcine EC with the tripeptide arginine-glycine-aspartic acid, as inhibitor of binding of Fg to integrin receptors, but not with the control tripeptide arginine-glycine-glutamic acid showed a decrease in chemotactic activity for cells cultured on Fg but not on Fn or G. Inhibition of protein kinase C (PKC) activity in EC by GF109203 resulted in a decrease of fibrinogen-induced chemotactic activity. Also the tyrosine-kinase inhibitor herbimycin inhibited fibrinogen mediated secretion of chemokines. The role of the PKC pathway for matrix mediated signal transduction is further corroborated by Fg-dependent induction of the PKC isoform delta. These data indicate an integrin-dependent signal transduction pathway leading to induction of chemotactic activity by the ECM protein fibrinogen. This mechanism may contribute to induction of chemokines in early atherosclerotic lesions.

Smoothelin is an indicator of reversible phenotype modulation of smooth muscle cells in balloon-injured rat carotid arteries

Restenosis is the major obstacle interfering with a successful long-term outcome of balloon angioplasty. Neointima formation following endothelial injury is the result of phenotype modulation and proliferation of smooth muscle cells (SMC). To characterize these time-dependent changes, a rat balloon injury model of carotid artery restenosis was assessed. We applied monoclonal antibodies recognizing desmin, sm-alpha-actin and smoothelin, a novel marker specific for the differentiated phenotype of SMC. Neointima formation could be seen from day 7 after injury onwards. During early phases, the number of smoothelin-positive cells in the media was decreased compared with uninjured controls. Smoothelin staining was absent in the neointima during formation. Increased levels of smoothelin in both media and neointima were observed at days 28 and 56, correlating with a decrease in proliferation as assessed by Ki-67 antigen staining. No such changes were observed for desmin and sm-alpha-actin. Following balloon injury, SMC in both the media and the neointima underwent an early, reversible dedifferentiation, followed by proliferation. The novel SMC-specific marker protein smoothelin can be used to monitor this SMC (de)differentiation in neointima and media. These findings support the pivotal role of SMC phenotype modulation in neointima formation and restenosis.

Low hepatic lipase activity is a novel risk factor for coronary artery disease

BACKGROUND

The crucial function of hepatic lipase (HL) in lipid metabolism has been well established, but the relationship between HL activity and coronary artery disease (CAD) is disputed.

METHODS AND RESULTS

We measured HL activity in the postheparin plasma of 200 consecutive men undergoing elective coronary angiography and determined the degree of CAD with the extent score, which has been shown to be better correlated with known risk factors than other measures of CAD extent. We found a significant inverse correlation between HL activity and the extent of CAD (r=-0.19, P<0.01). This association was mainly due to patients with HDL levels >0.96 mmol/L (n=94, r=-0.30, P<0.005). HL activity was lower in 173 patients with CAD than in 40 controls with normal angiograms (286+/-106 versus 338+/-108 nmol. mL(-1). min(-1), P<0.01). To correct for potential confounding factors, we performed multivariate analyses that confirmed the independent association of HL activity with CAD extent. In addition, the presence of the T allele at position -514 in the HL promoter, which leads to a reduced HL promoter activity, was associated with lower HL activity (r=0.30, P<0.001) and higher CAD extent (42.2+/-20.8 versus 35.3+/-23.6 [extent score], P<0.05). In patients with heterozygous familial hypercholesterolemia, calcified lesions in ECG-gated spiral computed tomography were higher in patients with low HL activity (6.3+/-6.8 versus 1.5+/-3.1, P=0.01).

CONCLUSIONS

Our data show that low HL activity is associated with CAD. Therefore, HL might be useful for CAD risk estimation and might be a target for pharmacological intervention.

[Results of single head VDD-stimulation]

VDD pacing systems provide a physiologic AV synchronous stimulation with only one lead in patients with high degree AV block and normal sinus node function. They compete with DDD systems.    This overview presents actual results of VDD stimulation concerning implantation, atrial sensing and AV synchrony, as well as stability of sinus node function. The results are partly compared with those of DDD systems. Furthermore, ventricular lead performance and cost effectiveness are discussed. New developments towards single-lead DDD stimulation are shown.    VDD systems have the advantage of shortening implantation times by up to 40% and fluoroscopy time is reduced by up to 55%. Additionally there is a non-significant trend towards fewer perioperative complications, as compared to DDD implantation. Comparable results for VDD and DDD systems have been shown for the reliability of P-wave sensing, and thereby AV synchrony, with mean values of 99% and above. Sinus node disease requiring atrial stimulation develops in about 1 to 2% of patients. This renders the missing atrial stimulation in VDD systems as not important. Ventricular lead function is similar in both systems. An advantage of VDD systems is their potential to reduce acute costs and during follow-up.    The results of actual studies demonstrate that VDD systems are established in the therapy of isolated high degree AV block. They are equal to the competing DDD systems and are, in some aspects, superior to them.

Use of intravascular ultrasound to compare effects of different strategies of lipid-lowering therapy on plaque volume and composition in patients with coronary artery disease

BACKGROUND

We studied whether lipid-lowering therapy with atorvastatin (target LDL cholesterol [LDL-C] <100 mg/dL) compared with a moderate treatment regimen that used other lipid-lowering drugs led to a lesser progression of atherosclerosis and to different changes in plaque echogenicity in patients with coronary artery disease.

METHODS AND RESULTS

This study was a 12-month, open-label, randomized, multicenter trial, which used serial 3D intracoronary ultrasound to calculate plaque volume and plaque echogenicity. After transcatheter therapy, 131 patients were randomized (atorvastatin n=65, usual care n=66). The target plaque had to be a minor lesion (ie, a diameter stenosis of <50% on angiography). After 12 months, mean LDL-C was reduced from 155 to 86 mg/dL in the atorvastatin group and from 166 to 140 mg/dL in the usual care group. Mean absolute plaque volume showed a larger increase in the usual care group compared with the atorvastatin group (usual care 9.6+/-28.1 mm(3), atorvastatin 1.2+/-30.4 mm(3); P=0.191). The hyperechogenicity index of the plaque increased to a larger extent for the atorvastatin group than for the usual care group, with a significant treatment effect for the percent change (atorvastatin 42.2%, usual care 10.1%; P=0.021).

CONCLUSIONS

One year of lipid-lowering therapy to <100 mg/dL LDL-C most likely led to a slowdown of plaque growth of minor lesions. The significantly larger increase in plaque hyperechogenicity is most likely due to a change in plaque composition.

Thrombin-induced MCP-1 expression involves activation of the p22phox-containing NADPH oxidase in human vascular smooth muscle cells

Activation of vascular smooth muscle cells (VMSC) by thrombin induces the expression of the chemokine, monocyte chemoattractant protein-1 (MCP-1). We investigated in cultured human and rat VSMC whether reactive oxygen species (ROS) derived from the vascular NADPH oxidase contribute to this effect. Exposure of cultured VSMC to thrombin rapidly increased ROS formation, phosphorylation of p38 MAP kinase as well as the expression of MCP-1. Specific inhibition of the p22phox subunit of the vascular NADPH oxidase using either p22phox neutralizing antibody or p22phox antisense oligonucleotides attenuated thrombin-induced ROS generation. Furthermore, thrombin-induced p38 MAP kinase activation as well as MCP-1 expression were impaired by antioxidants as well as by p22phox antisense oligonucleotides. Inhibition of p38 MAP kinase diminished the thrombin-induced expression of MCP-1.

CONCLUSION

Thrombin, by activating a p22phox-containing NADPH oxidase, elicits ROS generation and activation of p38 MAP kinase in VSMC. The subsequent induction of MCP-1 expression highligts the crucial role of the p22phox-containing NADPH oxidase in thrombin-induced signal transduction in VSMC.

Phosphorylation of cytokeratin 8 and 18 in human vascular smooth muscle cells of atherosclerotic lesions and umbilical cord vessels

Expression of cytokeratins (CK) is considered a hallmark of the state of epithelial differentiation. CK also occur in certain vascular smooth muscle cells (VSMC), inferring an association with a less differentiated phenotype. Recently, CK posttranslational modification was shown to occur in epithelial cells in stress, mitosis or apoptosis. The aim of this study was to determine potential CK phosphorylation patterns in human VSMC. Tissue samples of normal peripheral and coronary arteries, atherosclerotic lesions and umbilical cord vessels were evaluated by immunofluorescence microscopy applying antibodies specific for cytokeratins 8 and 18, specific cytokeratin phosphorylation sites, Ki-67-antigen as a proliferation marker and nick end labeling (TUNEL) to detect apoptosis. All samples contained cytokeratin-positive VSMC but diverse phosphorylation patterns. The C-terminal serine 431 of cytokeratin 8 (CK8Ser-431) was phosphorylated in the vast majority of CK-expressing VSMC of coronary artery lesions. Only a subset of these cells demonstrated phosphorylation of CK18Ser-33 or, to an even lesser extent, CK8Ser-73. DNA fragmentation occurred predominantly in samples containing cells with phosphorylated CK8Ser-431 domains. In contrast, occluded peripheral lesions exhibited little or no phosphorylation. Neonatal VSMC in umbilical cord vessels contain abundant phosphorylated CK domains, again predominantly CK8Ser-431, but also CK18Ser-33. Again, only single cells were found to be proliferating or to contain DNA fragmentation. Thus, abundant CK phosphorylation in VSMC of atherosclerotic lesions suggests a specific functional response to cell stress and a possible relation to apoptosis.

The terminal complement complex C5b-9 stimulates interleukin-6 production in human smooth muscle cells through activation of transcription factors NF-kappa B and AP-1

Activation of the complement system plays an important role in the pathogenesis of atherosclerosis. The proinflammatory cytokine interleukin (IL)-6 is potentially involved in the progression of the disease. We therefore investigated whether the terminal complement complex C5b-9 affects IL-6 production from vascular smooth-muscle cells (VSMC) and set out to determine the underlying signal transduction pathway. Stimulation of human VSMC with C5b-9 resulted in an increase of IL-6 transcript and production of IL-6 protein. Pretreatment with pertussis toxin or pyrrolidine dithiocarbamate inhibited complement-dependent IL-6 mRNA expression and IL-6 release, suggesting the involvement of Gi-proteins and nuclear factor-kB (NF-kB). C5b-9 also induced formation of reactive oxygen species, which, along with IL-6 release, was inhibited by the antioxidant N-acetylcysteine. C5b-9 activated the redox-sensitive transcription factors NF-kB and activator protein-1 (AP-1), which were both involved in the induction of IL-6 by C5b-9, as demonstrated by cis element double-stranded (decoy) oligonucleotides (ODN). The results demonstrate that activation of the complement system induces IL-6 release from human VSMC by a Gi-dependent pathway involving the generation of oxidative stressand the activation of the redox sensitive transcription factors NF-kB and AP-1. Our data support a new mechanism for the proatherogenic effect of the terminal complement complex.

Heparin-mediated selective release of hepatocyte growth factor in humans

AIMS

The aim of this investigation was to compare the effects of standard (S) with low molecular weight (LMW) heparin on circulating levels of heparin-binding growth factors (HBGF), known to have angiogenic properties in humans.

METHODS

In two consecutive trials 18 healthy male volunteers were studied on three separate occasions, following a placebo-controlled crossover design. Subjects were randomised to receive either S-heparin or LMW heparin or placebo. Heparins were administered either by intravenous (i.v.) or subcutaneous (s.c.) injection and saline placebo by i.v. injection. Serum concentrations of hepatocyte growth factor (HGF), vascular endothelial cell growth factor (VEGF) and basic fibroblast growth factor (bFGF) were measured before and up to 24 h after injection.

RESULTS

Administration of i.v. S-or LMW-heparin (50 IU kg(-1) resulted in rapid, highly significant (47 fold for S, 30.9 fold for LMW) increases in HGF serum values, reaching maxima of 10.51+/-1.65 ng ml(-1) (S) and 8.28+/-1.04 ng ml(-1) (LMW), respectively, 10 min after drug application. S.c. injection of S-heparin or LMW heparin resulted in 4.1 and 5.4 fold increases in HGF serum values, respectively. Both agents showed no effects on circulating VEGF or bFGF levels, independent of the route of administration.

CONCLUSIONS

Circulating HGF levels were selectively increased in response to pharmacological doses of two, widely used heparin preparations. This may, in part, explain some of the biological effects of heparin separate from its anticoagulant properties. By this mechanism, the systemic administration of heparin may facilitate collateral vessel formation in various clinical settings of tissue ischaemia.

Efficacy of single lead VDD pacing in patients with impaired and normal left ventricular function

Atrial synchronous ventricular pacing seems to be the best pacing mode for patients with advanced AV block and impaired LV function. The long-term follow-up of single lead VDD pacing was studied in 33 patients with impaired LV function and compared to 42 patients with normal LV function. All patients received the same VDD lead and VDDR pacemaker. The lead model with 13-cm AV spacing between the atrial and ventricular electrode was implanted in 89% of the patients. Follow-ups were 1, 3, 6, and 12 months after implantation. The percentage of atrial sensing and the P wave amplitude were determined at each follow-up. Minimal P wave amplitude at implantation was 2.0 +/- 1.4 mV in patients with impaired and 1.7 +/- 0.9 mV with normal LV function (not significant). At the 12-month follow-up, 33 patients with normal and 23 patients with depressed LV function remained paced in the VDD mode. The remaining patients died in five (impaired LV function) and seven cases (normal LV function) or their pacemakers were programmed to the VVI/VVIR pacing mode in four (impaired LV function) and three cases (normal LV function). P wave amplitude did not differ in the two groups (e.g., at month 12: impaired: 1.17 +/- 0.42 mV; normal: 1.09 +/- 0.49 mV). The atrial sensitivity was programmed in most patients to sensitive settings with no differences between the two groups (e.g., at month 12: impaired: 0.13 +/- 0.06 mV; normal: 0.13 +/- 0.05 mV). The diagnostic counters indicated nearly permanent atrial sensing (e.g., at month 12: impaired: 99.3 +/- 2.2%; normal: 99.0 +/- 1.0 mV). In conclusions, single lead VDD pacing restored AV synchronous ventricular pacing in patients with normal and with impaired LV function indicating that it could be an alternative to DDD pacemakers, but not to dual-chamber pacing.

[Fibrinolytic therapy in thrombosis of a mitral valve prosthesis]

A 48-year-old woman presented with progressive dyspnea due to thrombosis of a mitral valve prosthesis. The patient had undergone mitral valve replacement (St. Jude Medical) six years prior to admission because of mitral stenosis (Class III); three years later the prosthesis had to be replaced (St. Jude Medical) because of valve thrombosis. At admission, transesophageal echocardiography showed a thrombus on the atrial side of the fixed valve leaflet and a thrombus (2.4 x 1.6 cm) floating from the left atrial roof. Because of the previous thoracotomies, thrombolysis was initiated despite the mobile thrombus with the attendant risk of embolization. Urokinase was infused in a dose to maintain the fibrinogen level around 100 mg/dl. After 24 h, the mean pressure gradient across the prosthetic mitral valve (measured by doppler echocardiography) had decreased from 23 to 11 mmHg. After 13 days of this modified thrombolytic regimen, the clinical symptoms of the patient had resolved and echocardiography showed a normal function of the prosthetic mitral valve without evidence of residual thrombosis. This patient demonstrates that prolonged cautious thrombolysis can be effective for the treatment of prosthetic valve thrombosis in hemodynamically moderately compromised patients.

Medical progress and rationing of cardiological services

Due to the financial restrictions imposed on all national health services, the problem of allocating medical resources has gained new economical and political dimensions. Although each patient expects optimal treatment, the rationing of medical services make it increasingly difficult to provide the most adequate therapy. Health politicians and medical doctors have all advocated that health expenditures can be reduced by effective prevention of coronary heart disease, one of the main cost factors for all health services. Due to the introduction of statins, primary and secondary prevention of coronary heart disease can now be accomplished effectively. However, such treatment does not induce cost reduction, but rather an increase in costs. This applies predominantly to primary prevention. Treatment of all who would benefit from lipid lowering by statins would be prohibitively expensive for all national health care systems.

AT(1) receptor agonistic antibodies from preeclamptic patients cause vascular cells to express tissue factor

BACKGROUND

We recently described autoantibodies (angiotensin-1 receptor autoantibodies, AT(1)-AA) directed at the AT(1) receptor in the serum of preeclamptic patients, whose placentas are commonly infarcted and express tissue factor (TF). Mechanisms of how AT(1)-AA might contribute to preeclampsia are unknown. We tested the hypothesis that AT(1)-AA cause vascular smooth muscle cells (VSMC) to express TF.

METHODS AND RESULTS

IgG from preeclamptic patients containing AT(1)-AA was purified with anti-human IgG columns. AT(1)-AA were separated from the IgG by ammonium sulfate precipitation. We transfected Chinese hamster ovary cells overexpressing the AT(1) receptor with TF promoter constructs coupled to a luciferase reporter gene. VSMC were obtained from human coronary arteries. Extracellular signal-related kinase activation was detected by an in-gel kinase assay. AP-1 activation was determined by electromobility shift assay. TF was measured by ELISA and detected by immunohistochemistry. Placentas from preeclamptic women stained strongly for TF, whereas control placentas showed far less staining. We proved AT(1)-AA specificity by coimmunoprecipitating the AT(1) receptor with AT(1)-AA but not with nonspecific IgG. Angiotensin (Ang) II and AT(1)-AA both activated extracellular signal-related kinase, AP-1, and the TF promoter transfected VSMC and Chinese hamster ovary cells, but only when the AP-1 binding site was present. We then demonstrated TF expression in VSMC exposed to either Ang II or AT(1)-AA. All these effects were blocked by losartan. Nonspecific IgG or IgG from nonpreeclamptic pregnant women had a negligible effect.

CONCLUSIONS

We conclude that AT(1)-AA and Ang II both stimulate the AT(1) receptor and initiate a signaling cascade resulting in TF expression. These results show an action of AT(1)-AA on human cells that could contribute to the pathogenesis of preeclampsia.

Preclinical study on gene therapy of cervical carcinoma using adeno-associated virus vectors

Approximately 90% of cervical carcinomas are causally linked to infections with high-risk human papillomaviruses (HPVs), whose oncogenicity has been assigned to the continued expression of two early genes, E6 and E7. Reversal of the transformed phenotype by inhibiting E6/E7 gene expression therefore provides a suitable goal for future tumor therapy. Using recombinant adeno-associated virus type 2 (AAV-2) vectors, two types of therapeutic genes were expressed in cervical carcinoma cells with the aim of suppressing the E6/E7 oncogenes: (a) antisense E6/E7 and ribozyme genes and (b) the monocyte chemoattractant protein-1 (MCP-1) gene encoding MCP-1. Previous studies have shown that the MCP-1 protein is able to indirectly repress E6/E7 gene expression and is consistently absent in tumorigenic HPV-positive cervical carcinoma cell lines. Here, the effect of these therapeutic genes on tumor formation is analyzed in nude mice after ex vivo gene transfer into a HPV16- or HPV18-positive cervical carcinoma cell line (HeLa or SiHa, respectively). Whereas AAV-2 vector-mediated transfer of antisense or even ribozyme genes did not significantly influence tumor formation from implanted SiHa cells, the transfer and expression of human MCP-1 strongly inhibited the development of tumors derived from either HeLa or SiHa cells. Similar results were also obtained after in vivo delivery of these genes into SiHa-derived tumors. This suggests that transfer of therapeutic genes mediating a systemic effect via recombinant AAV-2 vectors offers a promising approach for the development of gene therapies directed against papillomavirus-induced human cancers.

Endothelin-1 and smooth muscle cells: induction of jun amino-terminal kinase through an oxygen radical-sensitive mechanism

Endothelin-1 (ET-1) has been proposed to contribute to atherogenesis and plaque rupture in coronary heart disease through activation of mitogen-activated protein kinases (MAPKs) in smooth muscle cells (SMCs). Reactive oxygen species (ROS) have been shown to be important signal transduction molecules in SMCs. Thus, the present study aimed to assess the role of ROS in ET-1-mediated activation of c-Jun amino-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) 1/2. Rat SMCs were exposed to ET-1 over time at concentrations from 10(-6) to 10(-10) mol/L, and MAPK activity was quantified. Activation of JNK and ERK was observed with a maximum stimulation at 10(-7) mol/L ET-1. JNK and ERK were activated by ET-1 binding to a single receptor (ET-1A) but differed in their downstream mechanisms: only JNK activation was sensitive to the radical scavenger N-acetylcysteine and diphenylene iodonium, an inhibitor of NADPH oxidase, indicating a role for ROS. The downstream MAPK effector and proinflammatory transcription factor, the activator protein-1 complex, was maximally activated 2 hours after the addition of ET-1. It was mainly composed of the JNK substrate c-Jun, and activation was also dependent on ROS formation. We suggest that plaque activation by ET-1 can be mediated through ROS. It can be hypothesized that the clinical benefit of antioxidants in the treatment of atherogenesis may partially depend on neutralization of ET-1-mediated ROS production.

Hydroxymethylglutaryl coenzyme A reductase inhibitors modify the inflammatory response of human macrophages and endothelial cells infected with Chlamydia pneumoniae

BACKGROUND

In patients with atherosclerosis, hepatic hydroxymethylglutaryl coenzyme A reductase (CSE) inhibitors may reduce the activation of inflammation. Because Chlamydia pneumoniae infection has been linked to coronary artery disease through the induction of plaque inflammation, we investigated whether cerivastatin affects the infection rate of human macrophages and endothelial cells (ECs) and their proinflammatory activation after chlamydial infection.

METHODS AND RESULTS

Macrophages were collected from the alveolar compartment of 6 volunteers and 10 patients with chronic bronchitis. ECs were obtained from 10 umbilical cords. The C. pneumoniae strain CWL was incubated with macrophages or ECs in the presence and absence of the CSE inhibitor cerivastatin. The infection rate was determined by immunofluorescence microscopy. The release of monocyte chemoattractant protein-1 (MCP-1), interleukin-8 (IL-8), and tumor necrosis factor (TNF)-alpha was quantified by ELISA. The release of oxygen radicals was determined by ferricytochrome assay. Infection rates were tendentially lower after the preincubation of macrophages with CSE inhibitors (17.2% versus 9. 3% and 18.2% versus 10.4%, respectively; P=NS). The secretion of MCP-1, IL-8, and TNF-alpha by infected macrophages from volunteers increased. Coincubation with cerivastatin resulted in significantly lower MCP-1 and IL-8 production, whereas the release of TNF-alpha remained unaffected. Similar effects regarding chemokine release were observed in ECs.

CONCLUSIONS

CSE inhibitors modify the inflammatory response of human immune cells to C. pneumoniae. This finding could be relevant for the therapeutic potential of CSE statins in patients with atherosclerosis and C. pneumoniae infection.

Differential activation of mitogen-activated protein kinases in smooth muscle cells by angiotensin II: involvement of p22phox and reactive oxygen species

The atherogenic effect of the renin-angiotensin system can be explained, in part, by the influence of its effector, angiotensin II (Ang II), on vascular smooth muscle cell (VSMC) growth. There is evidence that reactive oxygen species (ROS) play a role in the atherogenesis and activation of mitogen-activating protein (MAP) kinases, which are involved in proliferation and differentiation. The study was performed to further characterize the role of ROS in Ang II-mediated MAP kinase activation and the regulation of the transcription factor activator protein-1 (AP-1). Rat VSMCs were stimulated with Ang II. The activities of MAP kinases were assessed by Western blot analysis or by immunocomplex kinase assay. AP-1 binding was determined by using an electrophoretic mobility shift assay. Rat VSMCs were treated with Ang II-activated MAP kinases, extracellular signal-regulated kinase (ERK), c-Jun amino terminal kinase (JNK), p38 MAP kinase (p38 MAPK), and their downstream effector, AP-1. Interestingly, only the activation of ERK1/2, but not JNK or p38 MAPK, was tyrosine kinase, protein kinase C, and MEK1/2 dependent. Ang II also induced the rapid formation of ROS, which could be inhibited by a specific antibody as well as by antisense against the p22phox subunit of the NAD(P)H oxidase. JNK and p38 MAPK, but not ERK, activation was inhibited by an inhibitor of NAD(P)H oxidase. Antisense against p22phox also solely inhibited p38 MAPK but did not affect ERK. The results indicate that in VSMCs, Ang II activates MAP kinases and AP-1 through different pathways; the results further suggest that ROS, generated by p22phox, mediate Ang II-induced JNK and p38 MAPK activation, which may contribute to the pathogenesis of atherosclerosis.

Cardiac alpha-actin in smooth muscle cells: detection in umbilical cord vessels and in atherosclerotic lesions

Phenotypic modulation of smooth muscle cells (SMC) is a key event during the development of atherosclerotic and restenotic lesions. During this process, the composition of the cytoskeleton is substantially altered, with changes predominantly in actin expression reflecting a shift from smooth muscle alpha-actin to the non-muscle beta-isoform. We now demonstrate that yet another actin isoform, cardiac alpha-actin, is synthesized, de novo, in SMC of various atherosclerotic lesions. Using a highly specific monoclonal antibody against cardiac alpha-actin, we analyzed and compared the accumulation of this actin isoform in diverse SMC by immunofluorescence microscopy and immunoblotting. As expected, cardiac alpha-actin was present in human myocardium but not in healthy SMC of adult aorta, coronary arteries, trabeculae of the spleen, colon, stomach or skeletal muscle. Interestingly, the presence of cardiac alpha-actin was detected in umbilical cord vessels, human myometrium, in atherosclerotic coronary lesions and atherosclerotic lesions from peripheral vascular disease. The distribution of cardiac alpha-actin often paralleled that of cytokeratins 8 and 18, intermediate filament proteins typically found in dedifferentiated SMC. Taken together, the data presented here illustrate the expression of cardiac alpha-actin to be limited to either fetal vessels or those vessels or tissue having suffered damage or atrophy, outside its 'native' environment in the heart. The demonstration of cardiac alpha-actin in SMC of umbilical cord vessels and in atherosclerotic lesions but not in apparently healthy vessels supports the notion that SMC in atherosclerotic lesions exhibit a dedifferentiated phenotype.

ACE-Hemmer und arterielle Gefäßwand

Angiotensin-Converting-Enzyme-(ACE-)Inhibitoren können über ihre blutdrucksenkende Wirkung hinaus vasoprotektiv sein. Dabei gibt es sowohl Ergebnisse aus experimentellen Studien als auch eine zunehmende Anzahl klinischer Daten, die zeigen, daß ACE-Inhibitoren einen antiatherogenen Effekt haben. Es gibt Hinweise, daß ACE-Inhibitoren auch den Einfluß von vaskulären Risikofaktoren wie dem oxidativen Streß abschwächen können. Weiterhin konnte gezeigt werden, daß die inflammatorische Reaktion der Gefäßwand günstig beeinflußt werden kann. Arbeiten der jüngsten Zeit weisen darauf hin, daß vor allem Risikogruppen von der Gabe eines ACE-Hemmers hinsichtlich vaskulärer Morbidität und Mortalität profitieren. Obwohl die Mehrzahl der Studien bislang auf die koronare Herzkrankheit beschränkt war, gibt es Hinweise, daß die Atherosklerose auch an nichtkoronaren Gefäßen durch eine ACE-Hemmung günstig beeinflußt wird. Zum gegenwärtigen Zeitpunkt sind jedoch trotz der Vielzahl an Daten weitere Untersuchungen zum Mechanismus der vaskulären Wirkung von ACE-Hemmern notwendig, bevor eine abschließende Beurteilung ihrer Bedeutung bei der Behandlung der Arteriosklerose erfolgen kann.

JNK and c-Jun but not ERK and c-Fos are associated with sustained neointima-formation after balloon injury

BACKGROUND

Formation of neointima after balloon angioplasty is regulated via inducible transcription factors (ITF), such as c-Jun and c-Fos, depending on mitogen activated protein (MAP) kinases, which have been shown to be activated after balloon injury. The precise localization of activated MAP-kinases and concomitant expression of transcription factors in the vessel wall remains to be elucidated. We have now studied the localization and time-dependent expression of MAP-kinases together with corresponding ITFs in the rat carotid angioplasty model.

DESIGN

Animals were sacrificed at 0. 5, 6 and 24 h and 3, 5, 7, 14 and 28 days after injury. Cryocut sections were stained using antibodies directed against c-Jun, phosphorylated c-Jun, c-Fos, c-Jun amino-terminal kinase (JNK), extracellular signal related kinase (ERK), von Willebrand factor, ki67 antigen, and alpha-actin.

RESULTS

c-Jun expression was strongly induced in smooth muscle cells (SMC) 30 min after injury and remained upregulated for 24 h, thereafter dropping to basal levels at day 3. Re-expression was observed at day 7 and 14 but not day 28. Expression patterns of JNK and phosphorylated c-Jun were highly congruent to that of c-Jun. In contrast, c-Fos expression was restricted to 30 min and, less pronounced than c-Jun and JNK, was visible after 7 days. Also, its expression was congruent with the presence of ERK.

CONCLUSIONS

These findings demonstrate a clear association between MAP-kinases and their transcription factor substrates in vivo with a predominant association of JNK and c-Jun with sustained SMC proliferation.

3-deazaadenosine prevents adhesion molecule expression and atherosclerotic lesion formation in the aortas of C57BL/6J mice

Adhesion molecules such as vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) play an important role during the development of atherosclerosis. 3-Deazaadenosine (c(3)Ado), an adenosine analogue, inhibits endothelial-leukocyte adhesion and ICAM-1-expression in vitro. We hypothesized that c(3)Ado is able to prevent the expression of adhesion molecules and atherosclerotic lesion formation in female C57BL/6J mice. The animals were placed on an atherogenic diet with or without c(3)Ado for 9 weeks. Frozen cross sections of the proximal ascending aorta just beyond the aortic sinus were stained with oil red O, hematoxylin, and elastic van Gieson's stains and were analyzed by computer-aided planimetry for fatty plaque formation and neointimal proliferation. Monoclonal antibodies against CD11b (macrophages), VCAM-1, and ICAM-1 were used for immunohistochemistry. Mice on the atherogenic diet demonstrated multiple (5.4+/-1.6 per animal) lesions covering 3.4+/-2.8% of the endothelium and a marked neointima when compared with control mice (4501+/-775 versus 160+/-38 microm(2), P<0.001). Mice on the cholesterol-rich diet without c(3)Ado showed strong endothelial coexpression of ICAM-1 and VCAM-1. Moreover, there was a 10-fold increase in monocyte accumulation on the endothelial surface (33. 3+/-4.9 versus 3.8+/-1.2, P<0.004). In contrast, in mice treated with c(3)Ado, expression of ICAM-1 and VCAM-1 as well as monocyte adhesion and infiltration were almost completely inhibited. Furthermore, these mice did not show any fatty streak formation or neointima formation (125+/-32 microm(2)). Our results demonstrate that c(3)Ado can inhibit diet-induced fatty streak formation and the expression of endothelial ICAM-1 and VCAM-1 in C57BL/6J mice. This may provide a novel pharmacological approach in the prevention and treatment of atherosclerosis.

The lipoprotein lipase HindIII polymorphism: association with total cholesterol and LDL-cholesterol, but not with HDL and triglycerides in 342 females

BACKGROUND

Lipoprotein lipase (LPL) is the rate-limiting enzyme in the hydrolysis of core triglycerides in chylomicrons and VLDL.

METHODS

We investigated the association between the HindIII polymorphism of the LPL gene and fasting glucose, lipid, and lipoprotein concentrations in 683 Caucasians. We first stabilized the study subjects, using an 8-day diet and exercise intervention program before obtaining blood samples. The use of this standardization period reduced the variance of all glucose and lipid concentrations.

RESULTS

In our study, the HindIII allele frequencies for females and males were 0.29 and 0.34 for H- and 0.71 and 0.66 for H+, respectively. We found in females, but not in males, a significant association between the HindIII genotype and total cholesterol (P = 0.007) and LDL-cholesterol (P = 0.018), with females homozygous for the rare H- allele having the lowest, heterozygotes (H-/+) having intermediate, and women homozygous for the common H+ allele having the highest of each of these lipid traits. With regard to triglycerides, HDL-cholesterol, and glucose, no significant effect of the HindIII genotype was noted in either gender.

CONCLUSIONS

These results suggest that in a gender-specific manner, the rare LPL HindIII H- allele has a cholesterol-lowering and, therefore, potentially cardioprotective effect compared with the common H+ allele.

Expression of monocyte chemoattractant protein-1 cDNA in vascular smooth muscle cells: induction of the synthetic phenotype: a possible clue to SMC differentiation in the process of atherogenesis

In the arterial wall, smooth muscle cells (SMC) normally exist in a quiescent, differentiated state, representing the contractile phenotype. During the development of atherosclerosis SMC change towards the synthetic phenotype going along with proliferation, chemotactic response and increased monocyte binding. Expression of monocyte chemoattractant protein-1 (MCP-1), a potent chemoattractant for monocytes, has been shown to be among the earliest events in atherogenesis. We investigated the effect of MCP-1 on differentiated and dedifferentiated SMC. Differentiation of SMC was induced using Matrigel as a matrix for cultivation. MCP-1 was expressed in SMC by means of a recombinant adenovirus. Expression of MCP-1 led to dedifferentiation of SMC as demonstrated by induction of cytokeratin 18, a marker for the synthetic phenotype. Concurrently, migration was only detectable in MCP-1 expressing cells, whereas SMC infected with a control virus, coding for the nuclear-targeted lacZ gene showed no migration. The expression of intercellular adhesion molecule-1 (ICAM-1) could be demonstrated in synthetic SMC and was induced after infection of differentiated cells with recombinant adenovirus, coding for MCP-1 (AdMCP-1). Expression of ICAM-1 was associated with a tenfold higher monocyte binding compared to lacZ infected cells. Our data suggest that MCP-1 plays an important role for SMC in the functional switch from the contractile to the synthetic phenotype in the course of atherogenesis.

Effects of HMG-CoA reductase inhibition on PDGF- and angiotensin II- mediated signal transduction: suppression of c-Jun and c-Fos in human smooth muscle cells in vitro

Hydroxymethylglutaryl-Coenzyme A (HMG-CoA) reductase inhibitors were shown to be effective in primary and secondary prevention of coronary heart disease. The beneficial effect of statins is generally attributed to their cholesterol lowering activity. However recent work points to additional cholesterol independent effects of these drugs on cellular signal transduction. In this study it was investigated whether HMG-CoA reductase inhibition could affect induction of the transcription factors c-Jun and c-Fos in smooth muscle cells, which play an important role in atherogenesis. SMC were preincubated for 12 h with or without lovastatin (5 microM) and subsequently stimulated with platelet derived growth factor (PDGF, 10 ng/ml) or angiotensin II (0.1 microM) for 1, 2, 4 and 12 h or with phorbol myristate acetate (100 pM) for 2 h. Stimulation in the absence of the HMG-CoA reductase inhibitor led to a significant induction of c-Jun and c-Fos. Lovastatin inhibited, PDGF-, angiotensin II- and PMA-mediated induction. Concomitant addition of mevalonate, farnesylpyrophosphate and geranylgeranylpyrophosphate prevented the effects of HMG-CoA reductase inhibition resulting in rescued expression of c-Jun and c-Fos. The suppression of these transcription factors was associated with a complete growth arrest. Viability was not affected by pretreatment with the HMG-CoA reductase inhibitor. The data demonstrate that lovastatin can suppress PDGF- and angiotensin II-mediated induction of c-Jun and c-Fos protein in human SMC. This inhibitory effect may prevent activation of numerous growth factor- and cell cycle- genes. Whether these findings contribute to the effects of statins in atherosclerosis remains to be further investigated.

[Primary and secondary prevention of coronary heart disease: what can we afford?]

In secondary prevention, statins are cost-effective and even more cost-effective than other lipd lowering drugs. Statins are especially favorable in patients with previous myocardial infarction compared to those with angina pectoris. For secondary prevention of coronary heart disease, statins should be administered generously. In primary prevention, statins are effective but not cost-efficient. Unfavorable results have to be expected especially in premenopausal women, younger patients, and in those with a low risk factor profile. For population based primary prevention, only dietary measures can be advocated; however, apart from a serious lack of compliance their efficiency has not yet been proven. Preventive measures have their own prize; in general they are considered not to prevent coronary heart disease but retard it. Therefore, such therapeutic interventions can be assumed not to reduce but rather to increase the "direct" medical costs. Furthermore, successful prevention of coronary heart disease leads, due to life-prolongation, to an increase in people out of work and in disabled patients due to age and/or disease. Therefore, an increase especially of the "indirect" costs for unemployment, pension, nursing homes, etc. must be expected.

Acute effects of haemodialysis on cutaneous microcirculation in patients with peripheral arterial occlusive disease

BACKGROUND

Peripheral arterial occlusive disease (PAOD) is an increasing problem in patients on maintenance haemodialysis. Alterations in microvascular perfusion accompany and complicate arteriosclerosis of large vessels and might contribute to the disease process. The aim of the study was to investigate the acute effects of haemodialysis on the cutaneous microcirculation in 26 patients with and without intermittent claudication.

METHODS

Cutaneous perfusion was assessed by measuring transcutaneous oxygen pressure (tcPO2) and skin temperature at the dorsum of the foot. After standardized cooling to 15 degrees C of a 2cm2 skin area, the time to reach baseline skin temperature was evaluated as an indirect parameter of reactive hyperaemia.

RESULTS

During haemodialysis, tcPO2 dropped significantly in both groups. The decrease in tcPO2 was more pronounced in patients with PAOD (20% vs 15% n.s.). The reactive hyperaemia response was reduced significantly in patients with intermittent claudication indicated by a prolonged time to reach baseline skin temperature after cooling. Values of tcPO2 and reactive hyperaemia did not reach baseline values at the end of haemodialysis in either group.

CONCLUSIONS

Nutritive skin perfusion is impaired during haemodialysis. These changes are more pronounced in patients with PAOD and persist after dialysis. These findings are relevant for the treatment of patients with vascular disease on maintenance haemodialysis.