Circulating activated endothelial cells in systemic lupus erythematosus: further evidence for diffuse vasculopathy

Circulating Endothelial Cells are Associated with Thromboembolic Events in Patients with Antiphospholipid Antibodies

BACKGROUND

 Endothelial damage has been described in antiphospholipid antibody (aPL)-positive patients. However, it is uncertain whether circulating endothelial cells (CECs)-which are released when endothelial injury occurs-can be a marker of patients at high risk for thrombosis.

METHODS

 Ninety-seven patients with aPL and/or systemic lupus erythematosus (SLE) were included. CECs were determined by an automated CellSearch system. We also assayed plasma levels of tissue factor-bearing extracellular vesicles (TF⁺/EVs) and soluble triggering receptor expressed on myeloid cells 1 (sTREM-1) as markers of endothelial dysfunction/damage.

RESULTS

 Patients' mean age was 46.1 ± 13.9 years, 77 were women. Thirty-seven had SLE and 75 patients were suffering from antiphospholipid syndrome. Thirty-seven percent of patients presented a medical history of arterial thrombosis and 46% a history of venous thromboembolism (VTE). Thirteen patients had increased levels of CECs (>20/mL), with a mean CEC level of 48.3 ± 21.3 per mL. In univariate analysis, patients with obesity or medical history of myocardial infarction (MI), VTE, or nephropathy had a significant increased CEC level. In multivariate analysis, obesity (odds ratio [OR] = 6.07, 95% confidence interval [CI]: 1.42-25.94), VTE (OR = 7.59 [95% CI: 1.38-41.66]), and MI (OR = 5.5 [95% CI: 1.1-26.6)] were independently and significantly associated with elevated CECs. We also identified significant correlations between CECs and other markers of endothelial dysfunction: sTREM-1 and TF⁺/EVs.

CONCLUSION

 This study demonstrated that endothelial injury assessed by the levels of CECs was associated with thromboembolic events in patients with aPL and/or autoimmune diseases.

Serum levels and gene polymorphisms of angiopoietin 2 in systemic lupus erythematosus patients

This study aimed to discuss association between serum Angiopoietin2 (Ang2) levels, Ang2 gene polymorphisms and systemic lupus erythematosus (SLE) susceptibility. It was carried out by 235 SLE, 342 other inflammatory autoimmune diseases patients and 380 healthy individuals. Serum Ang2 levels was examinated by ELISA, and Ang2 rs12674822, rs1823375, rs1868554, rs2442598, rs3739390 and rs734701 polymorphisms were genotyped using KASP. Increased Ang2 concentrations in SLE patients were observed compared with healthy controls and patients with other inflammatory autoimmune diseases. For allelic contrast, except for rs1823375 (P = 0.058) and rs2442598 (P = 0.523), frequencies of alleles for other polymorphisms were significantly different between SLE patients and controls. Genotypes for rs12674822 (TT), rs1868554 (TT, TA and TT+TA), rs734701 (TT) were negatively correlated with SLE susceptibility (OR = 0.564 for rs12674822; OR = 0.572, OR = 0.625, OR = 0.607 for rs1868554; OR = 0.580 for rs734701). Patients carrying rs1868554 T allele and rs3739390 G allele were more likely to develop hematuria (P = 0.039; P = 0.003). The G allele frequencies of rs12674822 and rs2442598 were higher in SLE patients with proteinuria (P = 0.043; P = 0.043). GC genotype frequency of rs3739390 was higher in patients with ds-DNA (+) (P = 0.024). In summary, SLE had increased serum Ang2, which may be a potential biomarker, and the polymorphisms correlated with SLE.

Circulating endothelial cells as predictor of long-term mortality and adverse cardiovascular outcomes in hemodialysis patients

Circulating endothelial cells (CEC) are thought to be markers of endothelial injury. We hypothesized that the numbers of CEC may provide a novel means for predicting long-term survival and cardiovascular events in hemodialysis patients. 54 hemodialysis patients underwent enumeration of their CEC number. We retrospectively analyzed their survival and incidence of adverse cardiovascular events. 22 deaths (41%) were noted over the median follow up period of 3.56 years (IQR 1.43-12) and 6 were attributed to cardiovascular deaths (11%) of which 1 (4%) was in the low CEC (CEC<20 cells/ml) and 5 (19%) in the high CEC (CEC≥20 cells/ml) group. High CEC was associated with worse cardiovascular survival (p = 0.05) and adverse cardiac events (p = 0.01). In multivariate analysis, CEC >20 cells/ml was associated with a 4-fold increased risk of adverse cardiac events (OR, 4.16 [95% CI,1.38-12.54],p = 0.01) while all-cause mortality and cardiovascular mortality were not statistically different. In this hemodialysis population, a single measurement of CEC was a strong predictor of long term future adverse cardiovascular events. We propose that CEC may be a novel biomarker for assessing cardiovascular risk in dialysis patients.

Endothelial Activation Markers as Disease Activity and Damage Measures in Juvenile Dermatomyositis

OBJECTIVE

Circulating endothelial cells (CEC), von Willebrand factor (vWF) antigen, P-selectin, and thrombomodulin are released from damaged endothelium, while decreases in circulating endothelial progenitor cells (CEPC) have been associated with poor vascular outcomes. We examined these markers in the peripheral blood of patients with juvenile dermatomyositis (JDM) and their correlations with disease assessments.

METHODS

Peripheral blood endothelial cells and biomarkers were assessed in 20 patients with JDM and matched healthy controls. CEC and CEPC were measured by flow cytometry, while vWF antigen and activity, factor VIII, P-selectin, and thrombomodulin were measured in plate-based assays. Disease activity and damage, nailfold capillary density, and brachial artery flow dilation were assessed. Serum cytokines/chemokines were measured by Luminex.

RESULTS

CEC, vWF antigen, factor VIII, and thrombomodulin, but not vWF activity, CEPC, or P-selectin, were elevated in the peripheral blood of patients with JDM. CEC correlated with pulmonary activity (r_s = 0.56). The vWF antigen correlated with Patient's/Parent's Global, cutaneous, and extramuscular activity (r_s = 0.47-0.54). CEPC negatively correlated with muscle activity and physical function (r_s = -0.52 to -0.53). CEPC correlated inversely with endocrine damage. The vWF antigen and activity correlated with interleukin 10 and interferon-gamma inducible protein-10 (r_s = 0.64-0.82).

CONCLUSION

Markers of endothelial injury are increased in patients with JDM and correlate with extramuscular activity. CEPC correlate inversely with muscle activity, suggesting a functional disturbance in repair mechanisms.

Determination of Circulating Endothelial Cells and Endothelial Progenitor Cells Using Multicolor Flow Cytometry in Patients with Thrombophilia

BACKGROUND/AIMS

Endothelial progenitor cells (EPCs) and circulating endothelial cells (CECs) have been described as markers of endothelial damage and dysfunction in several diseases, including deep venous thrombosis. Their role in patients with known thrombophilia has not yet been evaluated. Both EPCs and CECs represent extremely rare cell populations. Therefore, it is essential to use standardized methods for their identification and quantification.

METHODS

In this study, we used multicolor flow cytometry to analyze the number of EPCs and CECs in patients with thrombophilia with or without a history of thrombosis. Patients with hematological malignancies after high-dose chemotherapy and patients with acute myocardial infarction were used as positive controls.

RESULTS

EPC and CEC immunophenotypes were determined as CD45dim/-CD34+CD146+CD133+ and CD45dim/-CD34+CD146+CD133-, respectively. Increased levels of endothelial cells were observed in positive control groups. No significant changes in the number of EPCs or CECs were detected in patients with thrombophilia compared to healthy controls.

CONCLUSION

Our optimized multicolor flow cytometry method allows unambiguous identification and quantification of endothelial cells in the peripheral blood. Our results support previous studies showing that elevated levels of CECs could serve as an indicator of endothelial injury or dysfunction. Normal levels of CECs or EPCs were found in patients with thrombophilia.

Circulating endothelial progenitor cells and endothelial cells in moyamoya disease

INTRODUCTION

There is no well-recognized biomarker for accurately predicting outcome in the presence of moyamoya disease (MMD), a progressive occlusive cerebrovascular disease of the internal carotid arteries or their branches. The aim of this study was to investigate the presence of endothelial progenitor cells (EPCs) and circulating endothelial cells (CECs) in MMD and correlate the findings with clinical features.

METHODS

Patients with MMD (n = 66) were compared with healthy controls (n = 81). Blood samples were obtained from an antecubital vein and analyzed using flow cytometry. EPCs were defined as CD31⁺ CD45^dim CD34^br CD133⁺ and CECs as CD31^br CD45^- CD34^dim CD133^- . Univariate and multivariate linear regression analyses were carried out.

RESULTS

The CEC counts were significantly higher in the patients than in the controls (p = 0.008). In multivariate analysis, EPC counts were independently associated with age of patients with MMD (p = 0.049) and CEC counts were independently negatively associated with concomitant disease such as hypertension, diabetes mellitus, and coronary heart disease (p = 0.034).

CONCLUSIONS

This is the first study to investigate the presence of CECs in the plasma of patients with MMD, and the amount of CECs was negatively correlated with concomitant disease in these patients.

Circulating Angiogenic T Cells Are Increased in Lupus Nephritis Patients

BACKGROUND Patients with systemic lupus erythematosus (SLE), especially with lupus nephritis (LN), undergo vascular damage and repair during the course of the disease. Since the recently identified angiogenic T cells (Tang) are involved in endothelial repair coupled with endothelial progenitor cells (EPCs), this study investigated the circulating Tang cells in LN patients and their potential correlations with disease features. MATERIAL AND METHODS Circulating Tang cells and EPCs were assessed by flow cytometry in peripheral blood samples from 67 SLE patients; of these, 32 had LN and 30 were matched healthy controls (HCs). The plasma levels of interleukin IL-17, IL-8, and vascular endothelial growth factor (VEGF) were quantified by immunoassays. RESULTS The percentage of circulating Tang cells in LN patients was significantly increased as compared to the non-LN patients and HCs, and they were positively correlated with the level of EPC and VEGF. Additionally, circulating Tang cell percentages were positively correlated with the extent of proteinuria in LN patients. CONCLUSIONS The increased levels of circulating Tang cells in LN patients might play a role in the balance of endothelium dysfunction in these patients.

A new model for chronic diseases

Chronic diseases are defined diseases whose symptoms last for at least six months and tend to worsen over time. In Europe, they cause at least 86% of deaths. In this speculative unifying model I set a new hypothesis for the etiology of the majority of chronic diseases. The main aim is to put order and observe our organism in a systemic way, connecting pathologies we now see as disconnected phenomena, with the conceptual frameworks of complex systems and network medicine. Chronic diseases could be caused by a first unsolved acute infection. In case the pathogen cannot be completely eliminated, it becomes a persistent infectious. After the acute episode, some mild symptoms will occur and probably disappear; the chronic disease will remain latent over time. It will manifest even after years or decades, in the presence of another acute infection, a particular stress, trauma, or another event. The presence of the persistent infectious elicits changes in the immune and systemic regulation, and these processes degenerate over time. They will assume their rules and patterns, being independent from the initial stimulus. The key to understand the dynamics and individuality of chronic diseases is the immune system and its networks. The immune mechanisms that can lead to the persistent response are mainly the switch from the Th1 to the Th2 immunity and the molecular mimicry. The first persistent infectious will also modify the susceptibility to other pathogens, facilitating new infections and new consequent persistent infectious. From the immune point of view, our organism is divided into three compartments: the outer one, which comprehend all the surfaces in contact with the environment, the intermediate one, which comprehend the internal organs and tissues, and the innermost one, comprehending the Central Nervous System and the adluminal compartment of the seminiferous tubule. The immune key-role is played respectively by the mucosa-associated lymphoid tissue, the endothelium, the blood-brain barrier and blood-testis barrier. The chronic diseases follow a progressive scheme, involving the three compartments from the outer to the innermost one. The primer microorganism at the origin of the majority of diseases could be streptococcus, or staphylococcus. Both cause acute in children, with a great variability of responses and symptoms, and both cause molecular mimicry. This model can be tested and proved in more ways, I propose here some of them. It could pave the way to a radical change in our comprehension and therapeutic approaches to chronic diseases.

Nailfold capillaroscopy in systemic lupus erythematosus: A systematic review and critical appraisal

Nailfold capillaroscopy is an easy, non-invasive technique to assess microvascular involvement in rheumatic diseases. Multiple studies describe capillaroscopic changes in systemic lupus erythematosus (SLE), including a wide range of non-specific findings. On behalf of the European League Against Rheumatism (EULAR) study group on microcirculation in rheumatic diseases, a systematic review was done to obtain all original research studies (in English) in which SLE patients had capillaroscopy. Forty such studies are identified. This article firstly provides a résumé of the results of these studies according to capillaroscopic parameters (density, dimensions, morphology, haemorrhages), semi-quantitative assessment and qualitative assessment of capillaroscopy in SLE patients. Secondly, the correlations between capillaroscopic parameters in SLE patients and clinical and laboratory parameters (including auto-immune parameters) are outlined. The following capillaroscopic parameters are found to be significantly more prevalent in SLE patients compared to healthy controls: tortuous capillaries, abnormal morphology and haemorrhages. Hairpin-shaped capillaries are significantly less prevalent than in healthy persons. The semi-quantitatively determined nailfold capillaroscopic score (NFC score) in SLE patients is also higher than in healthy controls. Several correlations between clinical and laboratory parameters and capillaroscopic parameters are identified in the review. Disease activity is correlated with NFC score in seven studies, with abnormal morphology (i.e. "meandering") in one study and with haemorrhages in one study. Frequent attacks of Raynaud's phenomenon (RP) and gangrene are significantly correlated with dilated capillaries. In two studies a possible correlation between anti-SSA antibodies and lower density of capillaries is withheld. About other immune parameters conflicting results are found. In one study a significant negative correlation is found between 24-hour proteinuria and abnormal morphology (i.e. "meandering"). For the first time, an overview of the nailfold capillaroscopic changes that have been described in SLE and their correlations with clinical and laboratory findings is given. Further large-scale research on the identification of capillaroscopic changes in SLE and their correlations with standardised clinical and laboratory parameters, is ongoing at the EULAR study group on microcirculation in rheumatic diseases.

Serum Vascular Endothelial Growth Factor (VEGF) as a Biomarker for Disease Activity in Lupus Nephritis

BACKGROUND

Previous studies have shown that serum VEGF levels were elevated in patients with active systemic lupus erythematosus (SLE), especially in those with lupus nephritis (LN). In this case control study, we aimed to compare serum levels of VEGF in SLE patients between LN, non-LN and healthy participants to determine the association between serum VEGF levels and the activity and histological classes of lupus nephritis.

METHODS

Blood samples were obtained from 92 SLE patients (46 LN and 46 non-LN) and 26 controls. Data were collected from medical records. Serum VEGF assays were performed by specific, enzyme-linked immunosorbent assay kits (ELISA). Laboratory investigations included urinalysis, urine protein-creatinine ratio, serum creatinine, albumin and VEGF levels. Blood pressure, renal biopsy result and treatment were recorded. LN activity was evaluated using the renal subscale of the British Isles Lupus Assessment Group (rBILAG, 2004). The rBILAG measures blood pressure (diastolic and systolic), urine protein, serum creatinine, calculated glomerular filtration rate (GFR), presence of active urinary sediments and histological evidence of active nephritis.

RESULTS

Serum VEGF was elevated in SLE patients with LN compared with the non-LN group and healthy controls. The levels found were significantly higher in the sera of patients with active nephritis compared to those with quiescent nephritis (P = 0.024). The study did not find a statistically significant relationship between serum VEGF levels and histological classes of LN.

CONCLUSION

There was no significant difference of serum VEGF level between LN and non-LN SLE groups and between the non-LN group and healthy controls. However, there were increased levels of serum VEGF in the LN group, especially in patients with active nephritis as compared to quiescent nephritis group. This reflects the role of VEGF in the pathogenesis of lupus nephritis, however the clinical potential of this biomarker needs further study.

Melanoma cell adhesion molecule as an emerging biomarker with prognostic significance in systolic heart failure

Background: Melanoma cell adhesion molecule (MCAM) is a marker of endothelial damage. MCAM diagnostic and prognostic value was assessed in chronic heart failure (CHF). Materials & methods: 130 CHF patients and 32 controls were included in the study. Telephone follow-up lasted one year. End points were: death from all causes, and hospitalization with CHF exacerbation. Results: MCAM was higher in patients than in controls (p = 0.01). Receiver operator curve analysis revealed that MCAM may serve as a predictor of death (area under the curve: 0.8404; p < 0.002). Patients with MCAM above 500 ng/ml had worse prognosis (p = 0.03). NT-proBNP and age were independent predictors of death in multivariate analysis. Conclusion: The increased MCAM indicates endothelial damage in CHF and may serve as a marker of worse prognosis in these patients.

Relationship between insulin resistance and circulating endothelial cells in pre-eclampsia

Endothelial dysfunction and insulin resistance (IR) are established features of pre-eclampsia, however the cause and effect relationship between them remain unexplained. Circulating endothelial cells (CEC) are increased in pre-eclampsia and appear to correlate with the degree of endothelial dysfunction. We hypothesised that CEC count in pre-eclampsia would correlate with IR and might provide a simple measure of IR in pregnancies complicated by the disease. CEC count and IR were measured in 10 women with pre-eclampsia and 10 normal pregnant controls matched for maternal age, body mass index and gestational age during the third trimester. CEC count was determined using an established immunomagnetic bead separation method and IR was measured by the homeostasis model test. CEC count and IR were significantly increased in pre-eclampsia compared to normal pregnancy. However, there was no correlation between the CEC count and IR in pre-eclampsia. The data suggest that CEC count in pre-eclampsia is not a useful measure on its own of IR in pregnancies complicated by the disease.

Mycophenolate Mofetil as a Potential Therapeutic Option for Neuropsychiatric Lupus: A Case Report

Neuropsychiatric lupus manifests clinically in a multitude of syndromes. The lack of specificity of serological and radiological tests make the confirmation of its diagnosis a challenge. The pathophysiology of neuropsychiatric lupus is not well understood and its evidence-based pharmacological treatment remains unestablished. We describe a patient who had bipolar affective disorder and angiographic evidence of cerebral arteritis that resolved with immunosuppressive therapy alone. Concomitantly, there was lupus-associated acute pancreatitis. Immunosuppressive therapy with high-dose corticosteroids had initiated control of active disease. Azathioprine, subsequently commenced as the steroid sparing agent, was discontinued because of adverse-effects. Disease-remission was later achieved and maintained with mycophenolate mofetil and low-dose prednisolone for 4 years. Though further studies are needed to confirm this observation, mycophenolate mofetil, a well-tolerated and established therapy for lupus nephritis and showing promise for the treatment of an increasing number of lupus-related pathologies, may be considered as a therapeutic option for neuropsychiatric lupus.

Circulating endothelial cells and chronic kidney disease

Endothelial dysfunction may play a crucial role in initiation of the pathogenesis of vascular disease and atherosclerosis. The identification and quantification of circulating endothelial cells (CEC) have been developed as a novel marker of endothelial function. We describe, in great detail, mechanisms of endothelial dysfunction and CEC detachment. We also review the relationship between numbers of CEC and disease severity and response to treatment. In addition, we describe the possible clinical use of CEC in chronic kidney disease (CKD) and kidney transplantation. In summary, CEC have been developed as a novel approach to assess the endothelial damage. Measurement of the CEC level would provide an important diagnostic and prognostic value on the endothelium status and the long-term outcome of vascular dysfunction.

Decreased circulating endothelial progenitor cells as an early risk factor of subclinical atherosclerosis in systemic lupus erythematosus

OBJECTIVE

Endothelial progenitor cells (EPCs) play an important role in vascular damage repair and it has been suggested that a decreased number of these cells is associated with increased subclinical atherosclerosis. Our study aim was to evaluate whether the number of circulating EPCs in patients with SLE is associated with subclinical atherosclerosis, the presence of cardiovascular (CV) risk factors and SLE-specific factors.

METHODS

Forty-six female SLE patients were included. At the time of each patient's appointment, CV risk factors, SLE-specific factors and EPCs were assessed in peripheral blood by flow cytometry. Simultaneously, atherosclerosis was assessed by measuring the carotid-femoral pulse wave velocity (PWV) by Doppler velocimetry, intima media thickness (IMT) and carotid plaque by B-mode US scanning.

RESULTS

Patients were classificated according to PWV following the reference values adjusted by age and blood pressure published by the European Society of Cardiology. Patients with pathological values of PWV showed a significant decrease of circulating EPC percentage compared with normal PWV patients. Decreased EPC counts were also associated with certain risk factors, including hypertension, tobacco use, impaired glucose metabolism, and metabolic syndrome, and correlate with high levels of high-sensitivity CRP (hsCRP) or fibrinogen. The presence of carotid plaque and IMT measurement were unrelated with EPC quantification.

CONCLUSION

Patients with a reduced percentage of EPCs showed pathological arterial stiffness and association with certain CV risk factors, suggesting that the measurement of circulating EPCs can be used as a biological marker to determine subclinical atherosclerosis in SLE.

Circulating endothelial cells and their progenitors in systemic lupus erythematosus and early rheumatoid arthritis patients

OBJECTIVE

The aim of this study was to investigate the endothelial progenitor cell population in SLE and early RA patients and its potential relationships with disease features and cytokine serum levels.

METHODS

Endothelial progenitor cells (EPCs), mature EPCs (mEPCs) and endothelial cells (ECs) were measured in peripheral blood samples from 83 SLE and 85 early RA patients and 39 healthy controls by flow cytometry on the basis of CD34, VEGF receptor 2 and CD133 expression. Serum levels of IL-1β, IL-6, IL-8, IL-17, VEGF-A, IFN-α, TGF-β and GM-CSF were quantified by immunoassays. Clinical and immunological data were obtained by reviewing clinical histories.

RESULTS

Circulating EPCs were increased in SLE but not in early RA patients associated with an enhanced CD34(+) bone marrow-progenitor cell release but unrelated to disease features. The amount of mEPCs, however, was significantly higher in SLE patients presenting anti-SSA/SSB antibodies and/or malar rash, whereas the presence of specific autoantibodies was associated with EC counts in early RA and SLE patients. As expected, most cytokines tested were altered in both diseases but, interestingly, IFN-α levels, and to a lesser extent IL-6 and IL-1β, were associated with CD133 loss and increased mEPC number, whereas VEGF and TGF-β seem to exert an opposite effect.

CONCLUSION

Our results show that high IFN-α levels and/or the presence of disease-specific antibodies may identify a group of SLE patients with increased mEPC and EC counts, and consequently probably defective endothelial repair, thus supporting their use as surrogate biomarkers of endothelial damage and high cardiovascular risk.

A new approach for rapid and reliable enumeration of circulating endothelial cells in patients

BACKGROUND

Mature circulating endothelial cells (CECs) are surrogate markers of endothelial damage/dysfunction. A lack of standardized assays and consensus on CEC phenotype has resulted in a wide variation of reported CEC numbers (4-1300 per mL).

OBJECTIVES

Given the need for a quick, reliable, robust and validated CEC assay at an affordable price, we present a novel approach to enumerate CECs using a multi-parameter flow cytometric (FCM) method without immunological pre-enrichment.

METHODS

CECs were defined as CD34+, CD45neg, CD146+ and DNA+ events based on the immunophenotype of endothelial cells from vein-wall dissections. As CECs express high levels of CD34, we based our assay on absolute CD34 counts after analyzing all CD34 positive events in a total blood volume of 4 mL needed for a precise enumeration of CECs at a frequency of < 1 cell μL(-1).

RESULTS

The endothelial origin of CECs was confirmed by morphology, immunohistochemistry and gene expression. The new FCM assay was tested in parallel with a validated assay (i.e. CellSearch). CEC levels ranged from 4 to 79 CEC mL(-1) in healthy individuals and were significantly higher in patients with advanced solid malignancies (P = 0.0008) and in patients with hematological malignancies (P < 0.0001).

CONCLUSIONS

This flow cytometric method should be useful as a fast and economical assay to enumerate and characterize CECs.

Evaluation of vascular lesions using circulating endothelial cells in renal transplant patients

Objective: To investigate the correlation between circulating endothelial cells (CECs) and vascular lesions in renal allografts.

Methodology: Sixty-two renal transplant patients were divided into four groups according to biopsy data. CECs were isolated from peripheral blood with anti-CD136-coated immunomagnetic Dynabeads and counted by microscopy during biopsy. CEC numbers were compared in each group, as well as the correlation between CECs and C4d and vascular changes in different groups.

Result: CECs counts were higher in the acute rejection (AR) with endarteritis group than in the normal group (p < 0.01), acute tubular necrosis (ATN) group (p < 0.01) and chronic allograft nephropathy (CAN) group (p < 0.01), there were no difference among ATN, normal and CAN) group (p = 0.587). There was no difference among the normal group without hyaline, normal group with hyaline and CAN with hyaline group. An increasing CECs count was related to C4d-positive AR (p = 0.008; κ score = 0.519) and infiltration of inflammatory cells (p = 0.002, κ score = 0.573) in proximal tubule cells (PTCs). The CECs count decreased after intensive therapy in five patients (p = 0.001).

Conclusion: Elevation of the CEC count in blood was related to endarteritis. Elevation of CEC count was related to C4d deposition and infiltration of inflammatory cells in PTCs.

Clinical value of circulating endothelial cell detection in oncology

Given the importance of tumor vasculature in tumor biology and as a target for treatment, there is an increasing need for biomarkers that reflect effects impacting tumor vasculature accurately. Circulating endothelial cells (CECs) increase in number as a result of vascular damage in cancer and several other diseases. CEC count constitutes a promising tool for monitoring disease activity with potential to assess prognosis and response to treatment. Here, we address the current state-of-the-art of CEC enumeration as a biomarker in clinical oncology. We focus on technical issues concerning CEC detection, review results from clinical studies and explore future potential applications.

Circulating endothelial cells as a marker of vascular dysfunction in patients with systemic lupus erythematosus by real-time polymerase chain reaction

CONTEXT

Systemic lupus erythematosus (SLE) is associated with an increased risk of atherosclerosis; endothelial dysfunction represents the first step in its pathogenesis.

OBJECTIVE

To assess endothelial dysfunction in SLE by circulating endothelial cells (CECs) and to characterize SLE-specific factors that contribute to its appearance.

DESIGN

Case-control study was conducted on 60 subjects, divided into 2 groups: group A (30 patients with SLE) and group B (30 healthy sex- and age-matched controls). Total cholesterol, triglycerides, antinuclear antibodies, anti-double-stranded DNA antibodies, and C3 were determined in all patients. Systemic lupus erythematosus activity was assessed using the SLE Disease Activity Index. Endothelial function was assessed by means of flow-mediated dilation of the brachial artery using B-mode ultrasonography and relative quantification of CD 146 mRNA by real-time polymerase chain reaction.

RESULTS

The group of SLE patients was formed of 20 females and 10 males, with a mean age of 31.16 ± 9.69 years. The values of SLE-specific tests and SLE Disease Activity Index were represented by anti-double-stranded DNA antibodies 160 ± 40.5, C3 68.91 ± 11.91 mg/dL, total cholesterol 188.66 ± 49.63 mg/dL, triglycerides 143.41 ± 46.26 mg/dL, and SLE Disease Activity Index 12.66 ± 3.70. Values for flow-mediated dilation were 8.85% ± 2.02% (group A) and 20.33% ± 6.19% (group B), P < .001, and CECs were 300 ± 40.5 μL⁻¹ blood (group A) and 10 ± 2.5 μL⁻¹ blood (group B). The statistical analysis showed a strong inverse correlation between CECs and SLE Disease Activity Index, a strong correlation between CECs and C3, a strong correlation between CECs and anti-double-stranded DNA antibodies, and a moderate inverse correlation between CECs and total cholesterol.

CONCLUSION

Endothelial dysfunction is present in SLE patients even in the absence of traditional cardiovascular risk factors due to disease activity.

C-reactive protein induces release of both endothelial microparticles and circulating endothelial cells in vitro and in vivo: further evidence of endothelial dysfunction

BACKGROUND

Inflammation is pivotal in atherosclerosis. A key early event in atherosclerosis is endothelial dysfunction. C-reactive protein (CRP), the prototypic marker of inflammation in humans, is a risk marker for cardiovascular disease, and there is mounting evidence to support its role in atherothrombosis. CRP has been shown to promote endothelial dysfunction both in vitro and in vivo. Emerging biomarkers of endothelial dysfunction include circulating endothelial cells (CECs) and endothelial microparticles (EMPs). However, there is a paucity of data examining the effect of CRP on CEC and EMP production in vitro and in vivo.

METHODS

In this report, we treated human aortic endothelial cells (HAECs) with increasing concentrations of CRP (0-50 μg/mL) or boiled CRP. We counted CECs and EMPs by flow cytometry.

RESULTS

Although CRP treatment resulted in a significant increase in release of both CECs and EMPs, boiled CRP failed to have an effect. Pretreatment of HAECs with sepiapterin or diethylenetriamine NONOate, both of which preserve nitric oxide (NO), resulted in attenuation of CRP's effects on CECs and EMPs. CD32 and CD64 blocking antibodies but not CD16 antibody or lectin-like oxidized LDL receptor 1 small interfering RNA (LOX-1 siRNA) prevented CRP-induced production of CECs and EMPs. Furthermore, delivery of human CRP to Wistar rats compared with human serum albumin resulted in significantly increased CECs and EMPs, corroborating the in vitro findings.

CONCLUSIONS

We provide novel data that CRP, via NO deficiency, promotes endothelial dysfunction by inducing release of CECs and EMPs, which are biomarkers of endothelial dysfunction.

Assessment of serum vascular endothelial growth factor and nail fold capillaroscopy changes in systemic lupus erythematosus with and without cutaneous manifestations

Angiogenesis and microvascular endothelial injury play a role in the pathogenesis of systemic lupus erythematosus (SLE). Vascular endothelial growth factor (VEGF), a key regulator of angiogenesis, and nail fold capillaroscopy (NFC) have been investigated in few studies in SLE with no reports targeting SLE with cutaneous manifestations. To evaluate NFC changes and VEGF serum level in relation to disease activity in SLE patients with versus without cutaneous manifestations. Thirty SLE patients (15 with cutaneous manifestations [group I], 15 without [group II]) and 15 healthy controls were evaluated for VEGF serum levels, NFC changes and were related to disease activity. VEGF serum levels were significantly higher in patients than controls (median and interquartile range [IQR]: 2110.77, 471.09-4714.30 vs. 60.00, 14-366, respectively, P < 0.0001). VEGF cut-off value to predict SLE patients was more than 293 and to detect moderate and severe SLE activity was more than 422 pg/mL and more than 3800 pg/mL, respectively. Serum VEGF levels increased with increased disease activity (P < 0.05). It was significantly higher in group I than group II (median and IQR: 2624.74, 1801.39-4141.70 vs. 862.50, 180-2426.95, respectively, P < 0.05). Mean serum VEGF was significantly higher with NFC score 3 than 1 (P = 0.008). NFC score and SLE activity were significantly associated in patients (P < 0.05). Serum VEGF is significantly elevated in SLE patients with cutaneous manifestations and its cut-off values to detect different activity grades of SLE are identified. Abnormalities in NFC reflect the extent of microvascular involvement in SLE.

Dysfunctional, pro-inflammatory HDL directly upregulates monocyte PDGFRβ, chemotaxis and TNFα production

Accelerated atherosclerosis is a major co-morbid condition in autoimmune diseases. Monocytes are the main immune cell involved in atherosclerosis initiation. We hypothesized that dysfunctional, pro-inflammatory HDL (piHDL), which occurs in approximately half of SLE patients, might directly influence monocyte gene expression and function. SLE subjects were stratified into three groups: 1) carotid artery plaque+piHDL+,2) plaque-piHDL+,and 3) plaque-piHDL- (n=18/group). PDGFRβ was upregulated in primary monocytes from plaque+piHDL+patients and in THP-1 cells acutely treated in vitro with piHDL compared to normal HDL. THP-1 chemotaxis was enhanced after treatment with piHDL versus normal HDL. Abnormal migration was restored to normal levels by treatment with imatinib or an apoJ mimetic peptide. Increased piHDL-mediated TNFα protein levels were reduced with both inhibitors. Dysfunctional piHDL directly influences expression of a small number of transcripts and proteins, and piHDL inhibition through reducing piHDL oxidation or blocking PDGFRβ kinase activity restored normal monocyte chemotaxis.

Endothelial function and its implications for cardiovascular and renal disease in systemic lupus erythematosus

Vascular manifestations associated with systemic lupus erythematosus (SLE) span a broad range, including vasculopathy. An understudied pathway of this morbidity is a repair component. Recent studies have elevated the anti-injury biomarkers, adiponectin and membrane endothelial protein C receptor (EPCR), for consideration with roles to antagonize premature atherosclerosis and SLE nephritis, respectively. For example, adiponectin was found to serve as an independent predictor of carotid plaque, and its elevations were persistent over more than one visit. Unexpectedly, this biomarker was present despite clinical quiescence. In vasculopathy as a comorbidity to SLE nephritis, the persistent expression of membrane EPCR at peritubular capillaries may represent a response to the local cues of a deficit of active protein C. Under conditions of unresolved morbidity, higher levels of adiponectin and membrane EPCR may represent a physiologic attempt to limit further endothelial damage, and the observed increase in plaque and progression of SLE nephritis represent an overwhelming of this reparative process by disease-provoking stimuli.

C3a, TNF-alpha and interleukin myocardial expression in a case of fatal sudden cardiac failure during clinic reactivation of systemic lupus erythematosus

Isolated myocarditis, or dilated cardiomyopathy, is a rare and usually late clinical manifestation of systemic lupus erythematosus (SLE). Increased levels of complement split products are associated with disease activity. Injury of the vascular endothelium due to complement activation and immune complexes may contribute to the vasculopathy in SLE. We present a case of sudden cardiac failure and death in a 28-year-old Caucasian man, during reactivation of SLE. To explain the sudden cardiac failure, we looked for anti-tumour necrosis factor (TNF)- proportional, variant and anti-interleukin (IL) expression in cardiac cells, and anti-complement (anti-C)3a in small cardiac vessels. The immunohistochemical examination of heart specimens revealed a strong positive reaction in cardiac myocytes for antibodies anti-TNF- proportional, variant and IL-8, and a milder positive reaction for antibodies anti-IL-15 and IL-10. A strong positive reaction of C3a in small cardiac vessels was observed in all specimens. Furthermore, the expression of CD4 and CD8 showed a strong positive reaction in pericardium and valvular endocardium, and a lesser positivity in myocardial specimens. TNF appears to have played a major proinflammatory role in this fatal case.

Pure anti-dsDNA mAbs need chromatin structures to promote glomerular mesangial deposits in BALB/c mice

The glomerular targets for nephritogenic antibodies have been identified as membrane-associated chromatin fragments. The processes responsible for their deposition are poorly understood. To determine early events in antibody-mediated nephritis, we injected highly pure anti-dsDNA mAbs into BALB/c mice. Mice receiving one dose of anti-dsDNA mAbs were sacrificed 6 or 24 h later. No direct binding of mAbs to glomerular membranes or to the mesangial matrix was observed by immune electron microscopy. In contrast, repeated injections of the same antibodies over 4 weeks resulted in deposition of electron dense structures predominantly in the mesangial matrix. These structures contained mAbs and chromatin fragments as determined by co-localization immune electron microscopy. Biotinylated anti-dsDNA mAbs, injected into nephritic (NZB x NZW)F1 or MRL(lpr/lpr) mice were detected in newly formed electron dense structures within glomerular capillary membranes. There were no correlation between mAb affinity for DNA, as determined by surface plasmon resonance analyses, and ability to bind chromatin fragments in vivo. No direct binding of mAbs to inherent membrane antigens was observed. Quantification of DNA in sera before and after one single injection of antibodies revealed increased DNA levels at 6 h after injection of anti-dsDNA mAb, and lower levels after 24 h. Repeated injections of anti-dsDNA caused an increase in circulating DNA. These results indicate that availability of chromatin fragments, presumable in circulation, is important for glomerular mesangial matrix deposition of anti-dsDNA antibody-containing immune complexes in context of lupus nephritis.

Circulating endothelial cells are elevated in patients with type 1 diabetes mellitus

OBJECTIVE

Circulating endothelial cells (CECs) have emerged as vascular damage markers and are increased in type 2 diabetic patients. Since type 1 diabetes is associated with vascular damage, we hypothesized high CEC numbers in this patient population.

METHODS

Thirty-nine patients with type 1 diabetes and 39 controls were included. CECs were isolated using anti-CD146-coated Dynabeads, stained with Ulex lectin-1, and counted by fluorescence microscopy. Endothelial function was measured as flow-mediated dilation (FMD). Thiobarbituric acid reactive substances (TBARS), total glutathione levels (GSH), and paraoxonase (PON) activity levels were measured as oxidative stress markers.

RESULTS

Patients with type 1 diabetes mellitus had higher number of CECs (7.46+/-5.37 vs 2.13+/-1.13 cells/ml, P<0.001), lower FMD (7.87+/-2.19 vs 12.06+/-2.34%, P<0.001), higher TBARS (4.94+/-1.20 vs 3.07+/-0.75 nmol/MDA, P<0.001), lower GSH (206.12+/-98.06 vs 353.61+/-68.45 microM, P<0.001), and lower PON activity levels (89.10+/-17.82 vs 127.65+/-29.01 U/l, P<0.001) as compared to controls. There was positive correlation between CEC numbers and HbAlc levels (r=0.49, P=0.002). CECs and fasting glucose levels were not correlated. There was no correlation between the number of CECs and FMD. Furthermore, there were no correlations between the number of CECs and TBARS, GSH and PON activity levels. Multiple regression analysis showed that HbAlc levels (r(2)=0.40, P<0.009) were associated with CEC numbers.

CONCLUSION

CECs are elevated in patients with type 1 diabetes mellitus reflecting endothelial damage. This increase is dependent on long-term glucose control.

The biology of reactive intermediates in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune syndrome marked by autoantibody production. Innate immunity is essential to transform humoral autoimmunity into the clinical lupus phenotype. Nitric oxide (NO) is a membrane- permeable signaling molecule involved in a broad array of biologic processes through its ability to modify proteins, lipids, and DNA and alter their function and immunogenicity. The literature regarding mechanisms through which NO regulates inflammation and cell survival is filled with contradictory findings. However, the effects of NO on cellular processes depend on its concentration and its interaction with reactive oxygen. Understanding this interaction will be essential to determine mechanisms through which reactive intermediates induce cellular autoimmunity and contribute to a sustained innate immune response and organ damage in SLE.

Enhanced adhesive properties of endothelial progenitor cells (EPCs) in patients with SLE

Endothelial progenitor cells (EPCs) are a population of bone marrow-derived cells present in the peripheral circulation, which possess the ability to migrate into areas where angioneogenesis is required and differentiate upon adhesion into mature endothelial cells. EPCs have reparative properties, are able to combat ischemia and have previously been shown to be decreased in level and function in inflammatory conditions. Systemic lupus erythematosus (SLE) is a multi-organ autoimmune inflammatory disorder associated with significantly increased cardiovascular morbidity and mortality. To investigate the numbers and functional properties of EPCs among patients suffering from SLE, thirty-one patients suffering from active SLE (American College of Rheumatology criteria) as well as 54 healthy controls were recruited. Disease activity was assessed using the SLEDAI score. Peripheral blood mononuclear cells were isolated and EPC numbers evaluated by the colony-forming unit (CFU) method. Functional properties were evaluated by EPC adherence to fibronectin. No significant difference was found between numbers of circulating EPC colony-forming units (CFUs) among patients with SLE and healthy individuals. A significant increase in adhesive capacity of EPCs to immobilized fibronectin was evident in patients with SLE compared to controls. An increase in adhesive capacity of circulating EPCs was observed in patients with SLE which may be related to altered endothelial function.

Hemato-vascular origins of endothelial progenitor cells?

Numerous studies have suggested the presence of precursor cells in various tissues and organs with potential to differentiate into endothelial and mural cells, and contribute to blood vessel formation in different physiological and pathological circumstances. Although there is still a lack of consensus in the field regarding the origin, and phenotypic and functional characteristics of putative vascular progenitor cell populations, all agree that further studies are needed to fully explore and exploit their great potential as cell therapy for vascular diseases, as modulators of postnatal blood vessel formation, and as disease biomarkers. Herein, we will review the phenotypic and functional characteristics of endothelial progenitor/precursor cell types thought to be derived from the hematopoietic and vascular systems and contribute to postnatal blood vessel formation, and discuss their potential lineage relationships.

Association of plasma soluble E-selectin and adiponectin with carotid plaque in patients with systemic lupus erythematosus

BACKGROUND

Systemic lupus erythematosus (SLE) is associated with premature atherosclerosis but the mechanisms underlying this association are not understood. The role of endothelial dysfunction is hypothesized.

METHODS

In predominantly non-Caucasian patients with SLE (N=119) and controls (N=71), carotid ultrasonography was performed and circulating endothelial cells (CECs), soluble endothelial protein C receptor and gene polymorphism at A6936G, soluble E-selectin (sE-selectin), and adiponectin were assessed.

RESULTS

Carotid plaque was more prevalent among patients than controls (43% vs 17%, p=0.0002). Mean CCA IMT was greater in patients compared to controls (0.59+/-0.19 mm vs 0.54+/-0.11 mm, p=0.03). Among SLE patients, plaque was not associated with smoking, body-mass index, LDL, triglycerides, homocysteine, C-reactive protein, anti-ds DNA antibody, C3, C4, SLE activity, or medications. Age and levels of soluble E-selectin and adiponectin were significantly higher in the SLE patients with plaque compared to those without plaque in univariate and multivariate analyses. sE-selectin and adiponectin were found to serve as independent predictors of carotid plaque and that elevations were persistent over more than one visit. Unexpectedly, these biomarkers were present despite clinical quiescence.

CONCLUSION

Premature atherosclerosis is a consistent feature of SLE and extends across ethnicities. Higher levels of adiponectin may represent a physiological attempt to limit further endothelial damage already reflected by the elevation in sE-selectin and the observed increase in plaque represents overwhelming of this reparative process by atherogenic stimuli.

Circulating endothelial cells, microparticles and progenitors: key players towards the definition of vascular competence

The balance between lesion and regeneration of the endothelium is critical for the maintenance of vessel integrity. Exposure to cardiovascular risk factors (CRF) alters the regulatory functions of the endothelium that progresses from a quiescent state to activation, apoptosis and death. In the last 10 years, identification of circulating endothelial cells (CEC) and endothelial-derived microparticles (EMP) in the circulation has raised considerable interest as non-invasive markers of vascular dysfunction. Indeed, these endothelial-derived biomarkers were associated with most of the CRFs, were indicative of a poor clinical outcome in atherothrombotic disorders and correlated with established parameters of endothelial dysfunction. CEC and EMP also behave as potential pathogenic vectors able to accelerate endothelial dysfunction and promote disease progression. The endothelial response to injury has been enlarged by the discovery of a powerful physiological repair process based on the recruitment of circulating endothelial progenitor cells (EPC) from the bone marrow. Recent studies indicate that reduction of EPC number and function by CRF plays a critical role in the progression of cardiovascular diseases. This EPC-mediated repair to injury response can be integrated into a clinical endothelial phenotype defining the ‘vascular competence’ of each individual. In the future, provided that standardization of available methodologies could be achieved, multimarker strategies combining CEC, EMP and EPC levels as integrative markers of ‘vascular competence’ may offer new perspectives to assess vascular risk and to monitor treatment efficacy.

Circulating endothelial cells and angiogenic proteins in patients with systemic lupus erythematosus

The aim of our study was to assess absolute counts of different subpopulations of circulating endothelial cells (CEC) in patients with active and inactive systemic lupus erythematosus (SLE). We have also investigated a potential correlation of CEC numbers with serum levels of angiogenic proteins as well as with clinical and laboratory symptoms of the disease. For the first time in SLE, CEC were enumerated directly, by the ‘single platform’ method. Resting (rCEC), activated (aCEC) and progenitor (pCEC) endothelial cells were identified in patients with SLE and healthy volunteers using four-colour flow cytometry. Serum concentrations of angiogenic proteins (vascular endothelial growth factor, placental growth factor (PIGF), soluble vascular cell adhesion molecule and endoglin) were evaluated by ELISA. The SLE activity was scored according to the Systemic Lupus Activity Measure system. We found that total CEC number in patients with SLE was significantly higher (median 14.2/μL) than in the control group (median 3.3/μL) ( P < 0.0001). Absolute counts of aCEC, rCEC and pCEC (medians 4.9/μL, 6.8/μL and 2.3/μL, respectively) were also higher in patients with SLE than in healthy persons (medians 0.9/μL, 1.6/μL and 0.1/μL, respectively), with P < 0.0001 for all comparisons. There was no correlation between CEC or their subpopulations and SLE activity. Strong positive correlations were found between CEC, rCEC and pCEC numbers and serum levels of PIGF. Moreover, aCEC, rCEC and pCEC counts were significantly higher in SLE patients with leukopenia. In conclusion, our results show that absolute CEC counts and angiogenic proteins levels are elevated in patients with SLE as compared with healthy controls. These data may suggest that angiogenic process is involved in the pathogenesis of this disease.

Von Willebrand factor, red cell fragmentation, and disease activity in systemic lupus erythematosus

This study sought to determine whether the plasma levels of Von Willebrand factor (vWf) and the degree of red blood cell (RBC) fragmentation on peripheral smear correlate with disease activity in systemic lupus erythematosus (SLE). Forty consecutive patients who fulfilled the criteria for SLE were studied prospectively for 1 year. Patients were categorized according to the SLE Disease Activity Index (SLEDAI) as either active (>2) or inactive disease and followed up monthly (active) or quarterly (inactive). At each visit, patients were examined fully and had complete blood count, tests on antibodies to double-stranded DNA, C3, and C4 levels, and urinalysis. Citrated plasma was analyzed for vWf antigen by standard enzyme-linked immunosorbent assay. A Wright's stained blood smear was obtained and schistocytes were quantitated on blood smear. The number of schistocytes per 500 RBCs was determined and a schistocyte index (SI) was calculated. At baseline, vWf correlated with SLEDAI (r = 0.64, p < 0.01), SI correlated with SLEDAI (r = 0.62, p < 0.01), and vWf and SI correlated with each other (r = 0.41, p = 0.01). There was an inverse correlation between baseline C3 levels and vWf (r = 0.49, p = 0.0013) and C3 levels and SI (r = 0.40, p = 0.01). Over time, there was also a correlation of SLEDAI with vWf (r = 0.53, p = 0.002) and SI (r = 0.57;p = 0.002). The relation of vWf with SI approached but did not reach statistical significance (r = 0.37, p = 0.06). We found that the plasma levels of vWf and the degree of RBC fragmentation correlate with lupus disease activity over time. Therefore, inflammation in SLE may be associated with endothelial injury.

CD146-based immunomagnetic enrichment followed by multiparameter flow cytometry: a new approach to counting circulating endothelial cells

BACKGROUND

Circulating endothelial cells (CECs) have emerged as non-invasive biomarkers of vascular dysfunction. The most widely used method for their detection is CD146-based immunomagnetic separation (IMS). Although this approach has provided consensus values in both normal and pathologic situations, it remains tedious and requires a trained operator.

OBJECTIVES

Our objective was to evaluate a new hybrid assay for CEC measurement using a combination of pre-enrichment of CD146+ circulating cells and multiparametric flow cytometry measurement (FCM).

PATIENTS AND METHODS

CECs were determined in peripheral blood from 20 healthy volunteers, 12 patients undergoing coronary angioplasty, and 30 renal transplant recipients, and blood spiked with cultured endothelial cells. CD146+ cells were isolated using CD146-coated magnetic nanoparticles and labeled using CD45-fluorescein isothiocyanate and CD146-PE or isotype control antibody and propidium iodide before FCM. The same samples were also processed using CD146-based immunomagnetic separation as the reference method.

RESULTS

The hybrid assay detected CECs, identified as CD45(dim)/CD146(bright)/propidium iodide(+), with high size-related scatter characteristics, and clearly discriminated these from CD45(bright)/CD146(dim) activated T lymphocytes. The method demonstrated both high recovery efficiency and good reproducibility. Both IMS and the hybrid assay similarly identified increased CEC levels in patients undergoing coronary angioplasty and renal transplantation, when compared to healthy controls. In patients, CEC values from these two methods were of the same order of magnitude and highly correlated. Bland-Altman analysis revealed poor statistical agreement between methods, flerrofluid-FCM providing higher values than IMS.

CONCLUSION

This new hybrid FCM assay constitutes an accurate alternative to visual counting of CECs following CD146-based IMS.

Association of serum nitrate and nitrite levels with longitudinal assessments of disease activity and damage in systemic lupus erythematosus and lupus nephritis

OBJECTIVE

Reactive intermediate production is an essential component of the innate immune response that is induced during disease activity in murine lupus. This study was undertaken to determine whether a marker of systemic nitric oxide (NO) production correlates with prospectively studied disease activity in human systemic lupus erythematosus (SLE) and lupus nephritis patients.

METHODS

Eighty-three SLE patients and 40 control subjects were studied longitudinally. The SLE group included 23 patients with lupus nephritis documented by renal biopsy and 26 with a history of lupus nephritis. During each visit, following a 24-hour low-nitrate diet, traditional markers of disease activity and damage were determined. Serum nitrate plus nitrite (NOx) levels were determined by chemiluminescence detection.

RESULTS

NOx levels were higher in SLE patients than in controls during the first visit. In univariate longitudinal analyses, NOx levels were associated with SLE Disease Activity Index scores. In multivariate analyses, NOx levels were associated with serum levels of C3 and creatinine and the urinary protein:creatinine ratio. Among patients with lupus nephritis, those with proliferative lesions had higher NOx levels, and higher NOx levels were associated with accumulation of renal damage and lack of response to therapy.

CONCLUSION

This is the first study to prospectively demonstrate longitudinal associations between serum NOx levels and markers of SLE and lupus nephritis disease activity. The more pronounced association with proliferative lupus nephritis and with longitudinal response to lupus nephritis therapy provides a rationale for the study of reactive intermediates as biomarkers of disease activity and therapeutic targets in proliferative lupus nephritis.

Altered coronary vasomotor function in young patients with systemic lupus erythematosus

OBJECTIVE

Accelerated atherosclerosis is an important cause of morbidity and mortality in patients with systemic lupus erythematosus (SLE). Altered coronary microvascular function may act as a marker of changes that predispose to the development of significant coronary vascular disease. The purpose of this study was to compare coronary flow reserve (CFR) in a group of premenopausal women with SLE and a group of age-, sex-, and race-matched healthy control subjects.

METHODS

Coronary flow velocity in 18 premenopausal women with SLE (mean +/- SD age 29.4 +/- 5.9 years) and 19 matched healthy controls (mean +/- SD age 28.2 +/- 4.3 years) was assessed by transthoracic Doppler echocardiography after an overnight fast. The CFR was calculated as the ratio of hyperemic to baseline coronary blood flow velocity in the left anterior descending coronary artery. Hyperemia was induced by intravenous administration of adenosine triphosphate.

RESULTS

The mean +/- SD duration of SLE was 8.2 +/- 7.2 years (range 0.25-25 years), and the mean +/- SD score on the Systemic Lupus Erythematosus Disease Activity Index was 11.0 +/- 5.3 (range 4.0-21.0). Adequate recordings of flow velocity in the left anterior descending artery under both conditions were obtained using an ultrasound procedure in all study subjects. CFR was significantly lower in SLE patients as compared with control subjects (mean +/- SD 3.4 +/- 0.8 versus 4.5 +/- 0.5; P < 0.0001).

CONCLUSION

These findings provide evidence that coronary vasomotor function is impaired in patients with SLE and support the notion that many of these young patients have subclinical coronary artery disease.

Vascular endothelial growth factor in systemic lupus erythematosus: relationship to disease activity, systemic organ manifestation, and nailfold capillaroscopic abnormalities

INTRODUCTION

The aim of the study was to evaluate whether vascular endothelial growth factor (VEGF) serum level is associated with systemic organ involvement, microvascular changes as determined by nailfold capillaroscopy, and disease activity of systemic lupus erythematosus (SLE).

MATERIALS AND METHODS

Serum levels of VEGF were determined by an enzyme-linked immunosorbent assay in 47 SLE patients and in 30 healthy controls. Nailfold capillaroscopy was performed in all patients and healthy subjects.

RESULTS

Morphological changes were observed by nailfold capillaroscopy in 45 of 47 (95.7%) SLE patients. Mild capillary changes were found in 16 (34%), moderate in 21 (44.7%), and severe in 8 (17%) SLE patients. All patients with systemic organ involvement showed severe or moderate changes in nailfold capillaroscopy. In comparison with the control group, a higher serum concentration of VEGF in SLE patients was demonstrated (p<0.05). Furthermore, significant differences in VEGF serum concentration between SLE patients with systemic involvement and controls were found (p<0.01). Comparison between patients with active and inactive SLE according to SLEDAI score showed a significantly higher concentration of VEGF in the sera of patients with active SLE (p<0.01). The SLE patients with severe and moderate changes in nailfold capillaroscopy showed significantly higher VEGF serum levels than SLE patients with mild changes (p<0.05) or healthy controls (p<0.01). Moreover, the VEGF serum level correlated significantly with ESR (r=0.580, p<0.0001) and CRP (r=0.512, p<0.005).

CONCLUSIONS

Our data suggest that VEGF serum level may be a useful marker of disease activity and internal organ involvement in SLE patients. Abnormalities in nailfold capillaroscopy may reflect the extent of microvascular involvement and are associated with systemic manifestation in SLE.

Endothelial cells in peripheral blood of healthy subjects and patients with metastatic carcinomas

BACKGROUND

A lack of standardized assays and consensus of cell definition has lead to a wide variation in the reported range of circulating endothelial cells (CECs).

METHODS

An automated rare cell analysis system was used to enumerate nucleated, CD146+/CD105+/CD45- CECs in 4 mL of blood.

RESULTS

Recoveries of spiked HUVECs were linear over a range of 0-1,241 cells (R2>or=0.99) with recoveries of >or=70% at each spike level. Correlation coefficient values for interoperator variability and duplicate sample variation were (R2=0.99 and 0.90), respectively. Correlation of CEC counts between tubes 1-2 and 2-3 drawn from the same subject in sequence differed (R2=0.48 and 0.63, respectively). The normal CEC reference range established in 249 healthy donors was 1-20 CECs/mL blood. CEC counts were significantly higher in the 206 metastatic carcinoma patients (P<0.0001).

CONCLUSION

CECs can be accurately and reproducibly enumerated in blood and are elevated in metastatic carcinomas compared with healthy donors. Phlebotomy procedures can affect endothelial cell counts.