Preclinical atherosclerotic burden in carotid and lower extremity arteries in adults with congenital heart disease.

Background: Over 90% of patients with congenital heart defects now reach adulthood, due to significant medical advances in recent decades. With advancing age, the risk of acquired cardiovascular diseases increases in addition to the already existing risk due to the congenital defect. The aim of this study was to evaluate the prevalence of atherosclerotic lesions in carotid and lower extremity arteries in adults with congenital heart disease (ACHD). Patients and methods: A total number of 108 ACHD patients (40.6±15.0 years, 50.0% male) and 22 healthy controls (39.3±16.6 years, 40.9% male) were included in this prospective study and underwent a comprehensive angiological examination that included vascular strain analysis on the common carotid artery. Results were stratified by the underlying ACHD lesion groups: shunt lesions (n=26), left-sided obstructive lesions (n=29), right-sided lesions (n=26) and complex lesions (n=27). Results: Colour-coded duplex sonography revealed atherosclerotic lesions in lower extremity arteries in 19 ACHD patients (17.6%). This prevalence did not significantly differ from the one assessed in controls (13.6%, p=0.77). All cases were asymptomatic and therefore classified as Fontaine stage I. 20.4% of ACHD patients presented atherosclerotic lesions in extracranial carotid arteries; amongst controls, the corresponding proportion was 18.4% (p=1.00). No significant differences were observed in atherosclerotic burden in extracranial carotid and lower limb arteries across the four ACHD patient groups (p=0.67 and p=0.89, respectively). Vascular strain analysis revealed no differences between patients and controls. Though circumferential strain varied over ACHD groups (p<0.05), comparison of strain measurements across all specific underlying defect subgroups revealed no significant difference for any of the studied strain parameters. Conclusions: ACHD patients present an atherosclerotic burden in extracranial carotid and lower limb arteries and a vascular stiffness that is comparable to healthy controls.

High prevalence of peripheral and carotid artery disease in patients with interstitial lung diseases.

Background: Interstitial lung diseases (ILD) are a heterogenous group of diseases, which have pulmonary fibrosis, restrictive lung disease, and decreased diffusion capacity as a common final path. Premature death frequently results not from ILD itself but from comorbidities. Peripheral artery disease (PAD) is a common comorbid disease in different chronic lung diseases. The focus of the present study is to clarify the prevalence of PAD in ILD. Patients and methods: A total of 97 patients with ILD and 30 controls were included in the study. Patients with ILD were subdivided into two groups according to the progression of pulmonary fibrosis: progressive fibrosing and non-progressive fibrosing ILD (PF-ILD and nPF-ILD, respectively). All participants underwent standard angiological and pneumological diagnostic procedures including six-minute walking test, measurement of ankle-brachial-index, and colour-coded duplex sonography. Results: We observed no relevant differences in the baseline characteristics except age. Both, PF-ILD and nPF-ILD patients, presented with a highly increased incidence of atherosclerotic lesions compared to the control group (p<0.001). PAD was present in all patients with PF-ILD and in 73% of patients with nPF-ILD. These results were confirmed by age-adjusted regression analyses. Conclusions: The present results indicate that ILD is an independent risk factor for atherosclerosis. Patients with PF-ILD are more severely affected than nPF-ILD patients with age as a confounding variable. Atherogenesis in ILD may be mediated by increased cardiovascular risk, systemic inflammation and chronic hypoxemia.

Pseudoxanthoma elasticum - also a microvascular disease.

Background: Pseudoxanthoma elasticum (PXE) is a heritable recessive disease characterized by calcification and fragmentation of soft connective tissue. Besides progressive loss of vision, alternations of the skin, and early-onset atherosclerosis different reports have suggested a microvascular manifestation of PXE and restrictive lung disease. Aim of this study was to elaborate a specific pattern of capillary alterations in PXE as well as to contemplate a possible connection to restrictive lung disease. Patients and methods: 53 consecutive patients with PXE and 26 controls were studied. All patients underwent nailfold capillaroscopy, body plethysmography, capillary blood gas analysis, and venous puncture to assess titer of autoantibodies. Results: PXE was associated with highly pathological alterations of capillaries compared to control. Atypical capillaries, such as ramifications and bushy forms, as well as dilatations varied at highest significance (p < .001). This effect was mirrored by perivascular edema, density and tortuous capillaries. Titer of anti-nuclear autoantibodies were not elevated in patients with PXE. Further analysis revealed negative correlation between vital capacity and presence of atypical capillaries. Conclusions: This study firstly describes the pattern of nailfold capillaries in PXE. Capillaries are highly pathological and consist of ramifications and bushy forms as well as dilatations. Frequently, tortuous capillaries, pericapillary edema and reduced denseness of capillary loops occur. Frequency of atypical capillaries is negatively correlated with vital capacity which can be interpreted as further lead on restrictive lung disease.

Radial artery occlusion after cardiac catheterization and impact of medical treatment.

Background: The transradial artery approach is the preferred access for cardiac catheterization according to current guidelines. However, the most common complication is radial artery occlusion (RAO). Despite the rare indication for surgical reopening, the occluded radial artery is not available for further procedures or as a potential bypass graft. Still, treatment regimens for RAO are scarce. We now determined whether the addition of antithrombotic to antiplatelet therapy improves the rate of partial or complete regain of patency in RAO following transradial cardiac catheterization in a retrospective analysis. Patients and methods: In a two-center tertiary referral hospital retrospective analysis 4135 files of patients who had undergone transradial catheterization were screened for documented RAO. 141 patients were identified and 138 patients with complete information on the medical regimen and ultrasound examinations for a maximum of 3 months were included in the analysis, whereas 3 patients were excluded due to missing or incomplete follow-up information. Results: 3.3% of all patients that had undergone transradial catheterization featured an oligosymptomatic RAO, confirmed by color-coded duplex sonography. 21% of patients with additional anticoagulation regained full patency vs. 9% without additional anticoagulation (p = 0.07). 40% of patients with anticoagulation featured a partial or full regain of patency vs. 16% of patients without additional anticoagulation for a maximum of 3 months treatment (p = 0.006). No major bleedings were reported during the follow-up visits. Conclusions: RAO remains a rare complication of cardiac catheterization. The addition of antithrombotic therapy for 3 months appears to safely improve the partial or even full regain of radial patency in case of postinterventional RAO.

Modulation of carotid strain by statin therapy in atherosclerosis patients.

BACKGROUND: The beneficial effect of statin therapy on the progress of atherosclerotic disease has been demonstrated by numerous studies. Vascular strain imaging is an arising method to evaluate arterial stiffness. Our study examined whether an influence of statin therapy on the vessel wall could be detected by vascular strain imaging. PATIENTS AND METHODS: 88 patients with recently detected atherosclerosis underwent an angiological examination including ankle-brachial index (ABI), pulse wave index (PWI), central puls ewave velocity and duplex ultrasound. Captures for vascular strain analysis were taken in B-mode during ultrasound examination of the common carotid artery and evaluated using a workstation equipped with a speckle tracking based software. A statin therapy was recommended and after six months a follow-up examination took place. Meanwhile, the non-adherence of a group of patients (N = 18) lead to a possibility to observe statin effects on the vascular strain. RESULTS: In the statin non-adherent group the ABI decreased significantly to a still non-pathological level (1.2 ± 0.2 vs. 1.0 ± 0.2; p = 0.016) whereas it stagnated in the adherent group (1.0 ± 0.2 vs. 1.0 ± 0.2; p = 0.383). The PWI did not differ in the non-adherent group (180.5 ± 71.9 vs. 164.4 ± 75.8; p = 0.436) but under statin therapy it decreased significantly (261.8 ± 238.6 vs. 196.4 ± 137.4; p = 0.016). In comparison to the adherent group (4.2 ± 2.0 vs. 4.0 ± 1.8; p = 0.548) under statin therapy the radial strain decreased significantly in the non-adherent group (4.7 ± 2.0 vs. 3.3 ± 1.1; p = 0.014). CONCLUSIONS: Our findings reveal a beneficial influence of statin therapy on the arterial wall detected by vascular strain analysis.

Increased vascular occlusion in patients with pseudoxanthoma elasticum.

BACKGROUND: Pseudoxanthoma elasticum (PXE) is an autosomal recessive inherited multisystem disorder of the connective tissue caused by a loss-of-function mutation of the ABCC6 gene. It can affect the cardiovascular system, presumably leading to a high prevalence of atherosclerosis. PATIENTS AND METHODS: 46 PXE patients and 18 controls underwent an angiological examination consisting of measurement of ankle-brachial index (ABI), strain-gauge arterial reserve (SGAR), arterial resting perfusion, pulse wave index (PWI), central pulse wave velocity, and ultrasound examination. RESULTS: With an average age of 51.4 ± 12.4 years, 35/46 (76.1 %) of the PXE patients had atherosclerotic lesions, and 10 of them (28.6 %) had a chronic vascular occlusion of one or more peripheral vessels. 34/46 (73.9 %) had a pathologic ABI < 0.9, 15/42 (35.7 %) had a pathological SGAR < 10 mL/100 mL tissue/min, and 23/38 (60.5 %) had a pathological PWI > 180. The differences between the groups were statistically significant for ABI, arterial reserve, and PWI. CONCLUSIONS: In PXE patients atherosclerosis was found with a much higher prevalence than expected. Moreover, they were at very high risk for total vessel occlusions.
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N-3 vs. n-6 fatty acids differentially influence calcium signalling and adhesion of inflammatory activated monocytes: impact of lipid rafts.

BACKGROUND: Anti-inflammatory n-3 fatty acids (FA) like docosahexaenoic acid (DHA) opposed to the pro-inflammatory n-6 FA arachidonic acid (AA) might modulate lipid rafts within the cell membrane by differential incorporation. In inflammation, monocyte adhesion to endothelial cells is a crucial step mediated by intracellular calcium changes. We investigated whether lipid rafts mediate FA-induced modulation of adhesion and intracellular calcium. METHODS: In isolated human monocytes and monocytic U937 cells we measured adhesion to human umbilical vein endothelial cells (HUVEC) using a parallel flow chamber and a static assay, adhesion molecules by FACScan, and intracellular calcium by fluorescence. Monocyte lipid rafts were isolated by ultracentrifugation and submitted to gas chromatography for FA analysis. RESULTS: Pre-incubation with AA or DHA resulted in a predominant incorporation of the respective FA into raft compared to non-raft fraction. DHA as compared to AA significantly reduced monocyte adhesion and calcium release after stimulation with TNF-α while expression of adhesion molecules remained unchanged. Pre-treatment with a calcium chelator abolished the effect of FA on calcium and adhesion. Disruption of lipid rafts prevented FA-induced modulations. CONCLUSION: Incorporation of FA into lipid rafts seem to be crucial for modulation of adhesion under inflammatory conditions.

Impact of interstitial lung disease on left ventricular myocardial function.

BACKGROUND: Interstitial lung disease (ILD) comprises a wide variety of pulmonary parenchymal disorders within which progressive fibrosing ILD (PF-ILD) constitutes a phenotypic subset. By use of speckle tracking-based strain analysis we aimed to evaluate the degree of left ventricular (LV) dysfunction in progressive vs. non-progressive fibrosing ILD (non-PF-ILD). METHODS: A total of 99 ILD patients (mean age 63.7 ± 13.5 years, 37.4% female), composed of 50 PF-ILD and 49 non-PF-ILD patients, and 33 controls were prospectively enrolled and underwent conventional and speckle tracking echocardiography. Additional laboratory and pulmonary function testing, as well as six-minute walk test were performed. RESULTS: As compared to the non-PF-ILD cohort, PF-ILD patients exhibited a significantly impaired forced vital capacity (2.4 ± 1.0l vs. 3.1 ± 0.9l, p = 0.002), diffusion capacity for carbon monoxide (DLCO, 25.6 ± 16.3% predicted vs. 43.6 ± 16.67% predicted, p <0.001) and exercise capacity response as measured by the six-minute walk test distance (268.1 ± 178.2m vs. 432.6 ± 94.2m, p <0.001). Contrary to conventional echocardiographic LV parameters, both regional and global longitudinal LV strain measurements were significantly altered in ILD patients as compared to controls. No differences in LV strain were found between both patient groups. Significant correlations were observed between global longitudinal strain, on the one hand, and systemic inflammation markers, total lung capacity (TLC) and DLCO, on the other hand (high-sensitivity C-reactive protein: Pearson´s r = -0.30, p< 0.001; interleukin-6: Pearson´s r = -0.26, p = 0.007; TLC % predicted: Pearson´s r = 0.22, p = 0.02; DLCO % predicted: Pearson´s r = 0.21, p = 0.02). CONCLUSIONS: ILD is accompanied by LV dysfunction. LV functionality inversely correlates with the severity of the restrictive ventilatory defect and inflammation marker levels. These observations support the assumption of persistent low-grade systemic inflammation that may link systemic cardiovascular function to ILD status.

A RAND/UCLA-Modified VAS Study on Telemedicine, Telehealth, and Virtual Care in Daily Clinical Practice of Vascular Medicine.

Background: Telemedicine is increasingly used in several fields of healthcare, including vascular medicine. This study aimed to investigate the views of experts and propose clinical practice recommendations on the possible applications of telemedicine in vascular medicine. Methods: A clinical guidance group proposed a set of 67 clinical practice recommendations based on the synthesis of current evidence and expert opinion. The Telemedicine Vascular Medicine Working Group included 32 experts from Europe evaluating the appropriateness of each clinical practice recommendation based on published RAND/UCLA methodology in two rounds. Results: In the first round, 60.9% of clinical practice recommendations were rated as appropriate, 35.9% as uncertain, and 3.1% as inappropriate. The strongest agreement (a median value of 10) was reached on statements regarding the usefulness of telemedicine during the 2019 coronavirus disease (COVID-19) pandemic, its usefulness for geographical areas that are difficult to access, and the superiority of video calls compared to phone calls only. The lowest degree of agreement (a median value of 2) was reported on statements regarding the utility of telemedicine being limited to the COVID-19 pandemic and regarding the applicability of teleconsultation in the diagnosis and management of abdominal aortic aneurysm. In the second round, 11 statements were re-evaluated to reduce variability. Conclusions: This study highlights the levels of agreement and the points that raise concern on the use of telemedicine in vascular medicine. It emphasizes the need for further clarification on various issues, including infrastructure, logistics, and legislation.

Pseudoxanthoma elasticum is associated with cardiocirculatory inefficiency.

Pseudoxanthoma elasticum (PXE) is a rare, genetic, metabolic disease characterized by dystrophic calcification of elastic fibres in the skin, retina and vascular wall. Data on cardiac involvement are inconsistent. Hence, we aimed to evaluate cardiorespiratory response to incremental cardiopulmonary exercise testing (CPET) in PXE. A total of 30 PXE patients (54.0 ± 11.2 years, 40.0% male) and 15 matched controls underwent symptom-limited incremental CPET. PXE patients presented an impaired peak work rate as compared to controls (84.2 ± 16.0% vs. 94.7 ± 10.4%, p = 0.03) that was accompanied by a lower peak oxygen uptake (in % predicted and mL/min/kg), reduced increments in oxygen uptake per increments of work rate (ΔV´O2/ΔWR, 8.4 ± 3.0 mL/min/W vs. 11.3 ± 4.9 mL/ min/W, p = 0.02), lower peak oxygen pulse (78.0 ± 12.3% vs. 90.6 ± 19.6%, p = 0.01) and reduced minute ventilation at peak exercise (V´E, 66.2 ± 16.8% vs. 82.9 ± 25.2%, p = 0.02). To summarize, we presently observed impairment in mainly cardiocirculatory parameters, whilst no substantial ventilatory limitation was detected. The potential implications of this finding for PXE management warrant further study.

Pulmonary affection of patients with Pseudoxanthoma elasticum: Long-term development and genotype-phenotype-correlation.

Pseudoxanthoma elasticum (PXE) is a rare, heritable disease caused by various, mainly recessively transmitted mutations in the ABCC6 gene. Due to calcification of soft connective tissue phenotypic hallmarks are progressive loss of vision, alternation of the skin and early onset atherosclerosis. Beside these main features patients also suffer from impaired alveolar diffusion. The present study focused on impaired lung functioning based on a large cohort of patients with PXE, its long-term development, and genotype-phenotype correlation. Retrospectively, 98 patients and 45 controls were enrolled. All patients underwent body plethysmography and carbon monoxide diffusion testing. Of 35 patients three or more body plethysmographic records were available for long-term analysis. For genotype-phenotype analysis ABCC6 genotypes were grouped as two missense, mixed, or two nonsense mutations. Patients with PXE showed significantly reduced vital capacity (p < 0.05), diffusion capacity (p < 0.01), and diffusion transfer coefficient (p < 0.05). Over a mean period of 38 months diffusion capacity (p < 0.05) and diffusion transfer coefficient (p < 0.01) dropped significantly whereas lung volumes remained unchanged. Genotype-phenotype correlation revealed no connection between gene variants and lung functioning. In conclusion, PXE is accompanied by progressive reduction of alveolar diffusion indicating progressive alterations of lung tissue. Genotype-phenotype correlation with genotypes sorted as missense and nonsense mutations do not explain impaired lung functioning.

Therapy of Pseudoxanthoma Elasticum: Current Knowledge and Future Perspectives.

Pseudoxanthoma elasticum (PXE) is a rare, genetic, metabolic disease with an estimated prevalence of between 1 per 25,000 and 56,000. Its main hallmarks are characteristic skin lesions, development of choroidal neovascularization, and early-onset arterial calcification accompanied by a severe reduction in quality-of-life. Underlying the pathology are recessively transmitted pathogenic variants of the ABCC6 gene, which results in a deficiency of ABCC6 protein. This results in reduced levels of peripheral pyrophosphate, a strong inhibitor of peripheral calcification, but also dysregulation of blood lipids. Although various treatment options have emerged during the last 20 years, many are either already outdated or not yet ready to be applied generally. Clinical physicians often are left stranded while patients suffer from the consequences of outdated therapies, or feel unrecognized by their attending doctors who may feel uncertain about using new therapeutic approaches or not even know about them. In this review, we summarize the broad spectrum of treatment options for PXE, focusing on currently available clinical options, the latest research and development, and future perspectives.

Impairment of vascular strain in patients with obstructive sleep apnea.

BACKGROUND: Obstructive sleep apnea (OSA) is an independent risk factor for the development of cardiovascular diseases. Aim of this present study was to evaluate and extend recent research on the influence of obstructive sleep apnea on vascular strain. METHODS: A total number of 98 patients were integrated in the study. Patients were grouped according to the Apnea-Hypopnea-Index (AHI) in patients with mild-to-moderate OSA (5/h ≤ AHI < 30/h), severe OSA (AHI ≥ 30/h) and controls (AHI < 5/h). Groups were matched in age, body-mass-index and cardiovascular risks. Vascular strain of common carotid arteries was assessed by ultrasound speckle-tracking. A minor group of 30 patients and controls further underwent assessment of vascular strain of brachial and femoral arteries. Additionally, all patients underwent blood testing to reveal potential influences of inflammatory markers on arterial stiffness. In additional analysis we examined the effect of statin therapy on vascular strain. RESULTS: Patients with OSA showed significantly reduced values of vascular strain of common carotid arteries. Radial and circumferential strains were significantly lower in both patients with mild-to-moderate (p = .05) and patients with severe OSA (p = .001) compared to control. Vascular strain parameters of brachial and femoral arteries showed no consistent results. There were no significant correlations of inflammatory markers with vascular strain parameters. No significant differences in vascular strain were detected between statin and non-statin groups. CONCLUSION: Patients with OSA show significantly reduced vascular strain assessed by ultrasound-based speckle-tracking. Vascular stiffness increases with the severity of the disease. Target vessels to assess vascular strain in patients with OSA are common carotid arteries, whereas other sites of the arterial tree are not reliable. No significant impact of current statin therapy on vascular strain was found. Further studies are needed to evaluate potential benefit of statins in secondary prevention of atherosclerosis in OSA.

Carotid strain measurement in patients with pseudoxanthoma elasticum - Hint for a different pathomechanism?

Pseudoxanthoma Elasticum (PXE), caused by autosomal-recessive mutations in the ATP-binding cassette transporter (ABCC6) gene, is known for high prevalence of atherosclerosis. A novel method investigating elastic properties of arteries in atherosclerotic patients is vascular strain analysis. We compared 44 PXE patients with peripheral artery disease (PXE+PAD group) with 50 control patients, each 25 without (control group) and with PAD (PAD group). All participants underwent an angiological examination including ankle-brachial index (ABI) and were examined with speckle-tracking based vascular strain analysis of common carotid arteries, measuring radial displacement (r.Dis), radial velocity (r.Vel), radial strain (r.Str), circumferential strain (c.Str), radial strainrate (r.SR) and circumferential strainrate (c.SR). We found significant lower ABI in patients with PXE compared to all other groups (each p < 0.01). The vascular strain analysis resulted in significantly decreased values in the PAD group compared to PXE with PAD (each p ≤ 0.01) and controls without PAD (each p ≤ 0.05), whereas no significant difference could be found between PXE+PAD and controls without PAD. We found significant negative correlations between low strain values and a higher prevalence of PAD in non-PXE patients (r.Str r = -0.34; c.Str r = -0.35; r.SR: r = -0.51; c.SR: r = -0.53). In conclusion, PXE patients had similar values for arterial stiffness compared to controls without PAD in vascular strain analysis. In this group, arterial stiffness parameters were significantly higher compared to non-PXE PAD patients. It is worth to discuss whether PAD-like manifestations in PXE are a different kind of disease and might need another strategy in diagnostics and therapy.

Activation of Ca2+ -activated potassium channels is involved in lysophosphatidylcholine-induced monocyte adhesion to endothelial cells.

OBJECTIVE: Ca(2+)-activated K(+)-channels (BK(Ca)) play an important role in lysophosphatidylcholine (LPC)-induced endothelial dysfunction. Aim of our study was to investigate whether LPC-induced activation of BK(Ca) is also involved in monocyte adhesion to endothelial cells (EC). METHODS AND RESULTS: Measurement of membrane potential (MP) was performed using the fluorescence dye DiBAC. Adhesion of the monocytotic cell line U937 to EC was analysed by (3)[H]-thymidine-adhesion-assay. Expression of ICAM-1 and VCAM-1 were analyzed by FACS. LPC induced a hyperpolarization of EC in a dose-dependent manner with the maximum seen with 2 microM. This was prevented by the BK(Ca)-inhibitor iberiotoxin (IBX, 100nM). Adhesion of U937 cells to EC was increased after stimulation of EC with LPC. This effect was time-dependent with the maximum seen after 4h. LPC-induced adhesion was significantly reduced when EC were co-incubated with IBX, or NAD(P)H oxidase inhibitor diphenyleneiodonium (DPI, 5 microM) and also blocked by addition of 2-aminoethoxydiphenylborate (2-APB, 100 microM) or the calcium-chelator BAPTA (10 microM). Stimulation of U937 cells with LPC did not result in an increased adhesion to unstimulated EC. CONCLUSION: Activation of the endothelial BK(Ca) plays an important role in monocyte adhesion to endothelial cells.

Lipopolysaccharide-induced proliferation and adhesion of U937 cells to endothelial cells involves barium chloride sensitive hyperpolarization.

The adhesion of monocytes to the endothelium and their proliferation in the subendothelial space play an important role in atherosclerosis. Since the proliferation and migration of cells are influenced by the activity of ion channels, the aim of this study was to examine whether barium chloride (Ba(2+))-sensitive potassium channels (K(iCa)) are involved in lipopolysaccharide (LPS)-induced proliferation of monocytic U937 cells, and in the adhesion of these cells to endothelial cells. The adhesion of LPS-stimulated U937 cells to endothelial cells reached a maximum at a concentration of 5 microg/ml. This effect of LPS was completely abolished in the presence of Ba(2+) (100 micromol/l). In addition, LPS-induced proliferation was significantly reduced by Ba(2+) (control, 100%; LPS 5 microg/ml, 175%; LPS + Ba(2+) 100 micromol/l, 136%; n = 12, P < 0.05). To examine whether K(iCa) are activated by LPS, changes of U937 membrane potential were determined. LPS (5 microg/ml) caused a hyperpolarization of U937 cells indicating a flux of K(+) ions out of the cells. This effect was completely blocked by Ba(2+) (100 micromol/l). In conclusion, we demonstrate that LPS activates K(iCa) in U937 cells, which is responsible for LPS-induced adhesion of these cells to endothelial cells, and to the proliferation of U937 cells.

Statins inhibit hypoxia-induced endothelial proliferation by preventing calcium-induced ROS formation.

Pathological hypoxia plays an important role in many diseases, such as atherosclerosis, cancer, and rheumatoid arthritis. The aim of the present study was to examine the effects of different statins on hypoxia-induced endothelial cell signalling. Human umbilical cord vein endothelial cells (HUVEC) were treated with NaCN (CN, 2.5 mmol/l) to simulate a transient hypoxia. The CN-induced increase of endothelial cell numbers was significantly (n = 10, p < 0.01) reduced by the Ca(2+) chelator BAPTA (10 micromol/l), or the reactive oxygen species (ROS) scavenger N-acetylcysteine (ACC, 1 mmol/l), or the NAD(P)H-oxidase inhibitor diphenyleneiodonium (DPI, 5 micromol/l). In detail, cell numbers were (in percentage of control): 163.24 (CN), 90.06 (CN+ACC), 92.06 (CN+DPI). Intracellular-Ca(2+) and -ROS, analysed by fluorescence imaging, were significantly increased by CN. Interestingly, the CN-induced increase of ROS was in part Ca(2+)-dependent, whereas the Ca(2+) increase was not ROS-dependent. Simvastatin (5 micromol/l), fluvastatin (2.5 micromol/l), and cerivastatin (0.1 micromol/l) all reduced CN-induced proliferation, ROS generation and Ca(2+) increase. Cell viability was not reduced by the statins and the antiproliferative effect was completely reversed by mevalonate (500 micromol/l). In conclusion our study demonstrates that statins block hypoxia-associated endothelial proliferation by preventing the increase of Ca(2+) and ROS.