A systematic review and meta-analysis of circulating adhesion molecules in rheumatoid arthritis

BACKGROUND

The availability of robust biomarkers of endothelial activation might enhance the identification of subclinical atherosclerosis in rheumatoid arthritis (RA). We investigated this issue by conducting a systematic review and meta-analysis of cell adhesion molecules in RA patients.

METHODS

We searched electronic databases from inception to 31 July 2023 for case-control studies assessing the circulating concentrations of immunoglobulin-like adhesion molecules (vascular cell, VCAM-1, intercellular, ICAM-1, and platelet endothelial cell, PECAM-1, adhesion molecule-1) and selectins (E, L, and P selectin) in RA patients and healthy controls. Risk of bias and certainty of evidence were assessed using the JBI checklist and GRADE, respectively.

RESULTS

In 39 studies, compared to controls, RA patients had significantly higher concentrations of ICAM-1 (standard mean difference, SMD = 0.81, 95% CI 0.62-1.00, p < 0.001; I2 = 83.0%, p < 0.001), VCAM-1 (SMD = 1.17, 95% CI 0.73-1.61, p < 0.001; I2 = 95.8%, p < 0.001), PECAM-1 (SMD = 0.82, 95% CI 0.57-1.08, p < 0.001; I2 = 0.0%, p = 0.90), E-selectin (SMD = 0.64, 95% CI 0.42-0.86, p < 0.001; I2 = 75.0%, p < 0.001), and P-selectin (SMD = 1.06, 95% CI 0.50-1.60, p < 0.001; I2 = 84.8%, p < 0.001), but not L-selectin. In meta-regression and subgroup analysis, significant associations were observed between the effect size and use of glucocorticoids (ICAM-1), erythrocyte sedimentation rate (VCAM-1), study continent (VCAM-1, E-selectin, and P-selectin), and matrix assessed (P-selectin).

CONCLUSIONS

The results of our study support a significant role of cell adhesion molecules in mediating the interplay between RA and atherosclerosis. Further studies are warranted to determine whether the routine use of these biomarkers can facilitate the detection and management of early atherosclerosis in this patient group. PROSPERO Registration Number: CRD42023466662.

Relevance of circulating markers of endothelial activation for cardiovascular risk assessment in rheumatoid arthritis: a narrative review

Rheumatoid arthritis (RA) is associated with excessive cardiovascular mortality secondary to premature atherosclerosis, in which endothelial activation (EA) plays a central role. EA is characterized by loss of vascular integrity, expression of leucocyte adhesion molecules, transition from antithrombotic to prothrombotic phenotype, cytokines production, shedding of membrane microparticles and recruitment of endothelial progenitor cells. As EA is an early event in atherogenesis, circulating markers of EA are putative markers of vascular pathology and cardiovascular (CV) risk. After a presentation of biology of EA, the present review analyzed the available data regarding changes in EA markers in RA in link with the vascular pathology and CV events, discussed their relevance as biomarkers of CV risk and proposed future directions.

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.

Plasma concentration of selected biochemical markers of endothelial dysfunction in women with various severity of chronic venous insufficiency (CVI)-A pilot study

BACKGROUND

Although the endothelial dysfunction is considered to be implicated in the pathogenesis of chronic venous insufficiency (CVI) the endothelial status in patients with venous disorders is still not fully evaluated. Therefore the aim of the study was to measure the concentration of selected markers of endothelial dysfunction: von Willebrand factor (vWf), soluble P-selectin (sP-selectin), soluble thrombomodulin (sTM) and soluble VE-cadherin (sVE-cadherin) in CVI women who constitute the most numerous group of patients suffering from venous disease.

MATERIALS AND METHODS

Forty four women with CVI were involved in the study and divided into subgroups based on CEAP classification. Concentration of vWf, sP-selectin, sTM and sVE-cadherin were measured and compared with those obtained in 25 healthy age and sex-matched women.

RESULTS

It was found that the concentration of sTM increased and sVEcadherin decreased along with disease severity in CVI women. A significant rise of sTM was observed especially in CVI women, with the highest inflammation status reflected by hsCRP or elastase concentration, and in CVI women with a high oxidative stress manifested by an increased plasma MDA. A significant fall of circulating sVE-cadherin was reported in CVI women with moderate to highest intensity of inflammation and oxidative stress. There was no change in vWF and sP-selectin concentration at any stage of CVI severity.

CONCLUSIONS

The results of the present study demonstrate the presence of endothelial dysfunction in women suffering from CVI which seems to progress with the disease severity and may be associated with inflammation and enhanced oxidative stress.

Effects of acute exercise on circulating endothelial and progenitor cells in children and adolescents with juvenile idiopathic arthritis and healthy controls: a pilot study

BACKGROUND

Youth with juvenile idiopathic arthritis (JIA) may be at risk of poor cardiovascular health. Circulating endothelial progenitor cells (EPCs) and circulating endothelial cells (CECs) are markers of cardiovascular repair and damage, respectively, and respond to exercise. The objectives of this study were to compare resting levels of EPCs and CECs in JIA and controls, and to assess the effects of distinct types of exercise on EPCs and CECs in JIA and controls.

METHODS

Seven youth with JIA and six controls completed 3 visits. First, aerobic fitness was assessed. Participants then performed either moderate intensity, continuous exercise (MICE) or high intensity, intermittent exercise (HIIE) on separate days. Blood samples were collected at the beginning (REST), mid-point (MID) and end of exercise (POST) for determination of EPCs (CD31(+)CD34(bright)CD45(dim)CD133(+)) and CECs (CD31(bright)CD34(+)CD45(-)CD133(-)) by flow cytometry. Between group differences in EPCs and CECs were examined using two-way ANOVA, followed by Tukey's HSD post hoc, where appropriate. Statistical significance set at p ≤ 0.05.

RESULTS

Both EPCs and CECs were similar between groups at REST (p = 0.18-0.94). During MICE, EPCs remained unchanged in JIA (p = 0.95) but increased significantly at POST in controls (REST: 0.91 ± 0.55 × 10(6) cells/L vs. POST: 1.53 ± 0.36 × 10(6) cells/L, p = 0.04). Compared with controls, lower levels of EPCs were observed in JIA at MID (0.48 ± 0.50 × 10(6) cells/L vs. 1.10 ± 0.39 × 10(6) cells/L, p = 0.01) and POST (0.38 ± 0.34 × 10(6) cells/L vs. 1.53 ± 0.36 × 10(6) cells/L, p < 0.001) during MICE. No changes were detected in CECs with MICE in JIA and controls (p = 0.69). Neither EPCs nor CECs were modified with HIIE (p = 0.28-0.69).

CONCLUSION

Youth with JIA demonstrated a blunted EPC response to MICE when compared with controls. Future work should examine factors that may increase or normalize EPC mobilization in JIA.

A Pilot Study to Evaluate Haemostatic Function, following Shock Wave Lithotripsy (SWL) for the Treatment of Solitary Kidney Stones

Purpose

The number of patients undergoing shock wave lithotripsy (SWL) in the UK for solitary unilateral kidney stones is increasing annually. The development of postoperative complications such as haematuria and sepsis following SWL is likely to increase. Comparing a range of biological markers with the aim of monitoring or predicting postoperative complications following SWL has not been extensively researched. The main purpose of this pilot-study was to test the hypothesis that SWL results in changes to haemostatic function. Subsequently, this pilot-study would form a sound basis to undertake future investigations involving larger cohorts.

Methods

Twelve patients undergoing SWL for solitary unilateral kidney stones were recruited. From patients (8 male and 4 females) aged between 31–72 years (median—43 years), venous blood samples were collected pre-operatively (baseline), at 30, 120 and 240 minutes postoperatively. Specific haemostatic biomarkers [platelet counts, prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen, D-dimer, von Willebrand Factor (vWF), sE-selectin and plasma viscosity (PV)] were measured.

Results

Platelet counts and fibrinogen concentration were significantly decreased following SWL (p = 0.027 and p = 0.014 respectively), while D-dimer and vWF levels significantly increased following SWL (p = 0.019 and p = 0.001 respectively). PT, APTT, sE-selectin and PV parameters were not significantly changed following SWL (p>0.05).

Conclusions

Changes to specific biomarkers such as plasma fibrinogen and vWF suggest that these represent a more clinically relevant assessment of the extent of haemostatic involvement following SWL. Analysis of such markers, in the future, may potentially provide valuable data on “normal” response after lithotripsy, and could be expanded to identify or predict those patients at risk of coagulopathy following SWL. The validation and reliability will be assessed through the assessment of larger cohorts.

Markers of endothelial damage and repair in Takayasu arteritis: are they associated with disease activity?

The current clinical and laboratory parameters of Takayasu arteritis (TA) are insufficient for proper assessment of disease activity. The aims of this study were to investigate the markers of endothelial injury and repair, including circulating endothelial cell (CEC), circulating endothelial progenitor cell (CEPC) and vascular endothelial growth factor (VEGF), and evaluate their associations with disease activity in patients with TA. Thirty-two patients with TA and 30 healthy age- and sex-matched controls were included in this study. Disease activity was assessed in TA patients using various tools, including Kerr's criteria, the Indian Takayasu's Arteritis Scoring (ITAS2010) and physician's global assessment (PGA). CECs and CEPCs were measured by flow cytometry, and VEGF was measured using an enzyme-linked immunosorbent assay. The CEC level was found to be higher in TA patients than in the healthy controls (HC) (p < 0.001). There was no significant difference in CEC level between the active and inactive patients, but its level was slightly correlated with C-reactive protein (CRP) level. CEPC and VEGF levels in TA patients with active disease were higher than those in the inactive patients and HC. CEPC and VEGF levels were positively correlated with ITAS-CRP and PGA scores. This study shows increased level of CEC in patients with TA. It also suggests that the CEPC and VEGF levels may be correlated with disease activity.

Circulating brain microvascular endothelial cells (cBMECs) as potential biomarkers of the blood-brain barrier disorders caused by microbial and non-microbial factors

Despite aggressive research, central nervous system (CNS) disorders, including blood-brain barrier (BBB) injury caused by microbial infection, stroke, abused drugs [e.g., methamphetamine (METH) and nicotine], and other pathogenic insults, remain the world's leading cause of disabilities. In our previous work, we found that dysfunction of brain microvascular endothelial cells (BMECs), which are a major component of the BBB, could be caused by nicotine, meningitic pathogens and microbial factors, including HIV-1 virulence factors gp41 and gp120. One of the most challenging issues in this area is that there are no available cell-based biomarkers in peripheral blood for BBB disorders caused by microbial and non-microbial insults. To identify such cellular biomarkers for BBB injuries, our studies have shown that mice treated with nicotine, METH and gp120 resulted in increased blood levels of CD146+(endothelial marker)/S100B+ (brain marker) circulating BMECs (cBMECs) and CD133+[progenitor cell (PC) marker]/CD146+ endothelial PCs (EPCs), along with enhanced Evans blue and albumin extravasation into the brain. Nicotine and gp120 were able to significantly increase the serum levels of ubiquitin C-terminal hydrolase 1 (UCHL1) (a new BBB marker) as well as S100B in mice, which are correlated with the changes in cBMECs and EPCs. Nicotine- and meningitic E. coli K1-induced enhancement of cBMEC levels, leukocyte migration across the BBB and albumin extravasation into the brain were significantly reduced in alpha7 nAChR knockout mice, suggesting that this inflammatory regulator plays an important role in CNS inflammation and BBB disorders caused by microbial and non-microbial factors. These results demonstrated that cBMECs as well as EPCs may be used as potential cell-based biomarkers for indexing of BBB injury.

Circulating endothelial cell levels in psoriatic patients and their modification after an anti-TNF-alpha (Etanercept) treatment

BACKGROUND

Endothelial function in psoriatic patients has been mainly evaluated through a high-resolution ultrasound measurement of flow-mediated vasodilation in the brachial artery, which is an operator-dependent and technically demanding technique: this characteristic, together with different patient selection criteria, could account for the conflicting results emerging from different studies. Recently, Circulating Endothelial Cells (CECs) level has been suggested as a novel biomarker of vascular injury.

METHODS

The number of CECs was determined by a semi-automated immunomagnetic system (CellSearch system) in peripheral blood of psoriatic patients (n = 48) and healthy subjects (n = 50). In 15 patients, CEC level was also evaluated after 6 months of treatment with an anti-TNF-alpha agent, Etanercept. The plasma levels of high-sensitivity C-reactive Protein (CRP), E-selectin, VEGF and PAI-1 were measured by ELISA. The psoriasis severity was assessed by PASI score.

RESULTS

A statistically significant difference (P = 0.001) was found between CEC level in psoriatic patients (10.6 ± 9.4 cells/mL) vs. the control group (3.9 ± 0.9 cells/mL). This count inversely correlated with sE-selectin levels (r(2) = 0.16; P = 0.03). After 6 months of therapy, patients experienced a significant (P < 0.05) decrease in CEC levels (3.4 ± 1.3 cells/mL) and in PASI score (from 11.7 ± 8.1 to 2.1 ± 4.0).

CONCLUSIONS

The elevated CECs level that we found in a sample of high selected psoriatic patients could be expression of endothelial damage. Lowering of CECs count after treatment with Etanercept support the hypothesis that an effective systemic therapy of psoriasis may also improve the endothelial function.

Pilot study of vascular health in survivors of Hodgkin lymphoma

BACKGROUND

Vascular-related toxicities have been reported among survivors of Hodgkin lymphoma (HL), but their genesis is not well understood.

PROCEDURE

Fasting blood samples from 25 previously irradiated HL survivors were analyzed for biomarkers that can reveal underlying inflammation and/or endothelial cell activation: high-sensitivity C-reactive protein (hsCRP), triglycerides, total cholesterol, high-density lipoprotein (HDL), apolipoprotein ß, lipoprotein (a), fibrinogen, circulating endothelial cells (CECs), and vascular cell adhesion molecule-1 (VCAM-1) expression. Values were compared to subjects in the Coronary Artery Risk Development in Young Adults (CARDIA) study. CECs and VCAM-1 were compared to healthy controls.

RESULTS

Survivors (76% male), median age 17.6 years (5-33) at diagnosis, 33.0 years (19-55) at follow-up, included stages IA (n = 6), IIA (n = 10), IIB (n = 2), IIIA (n = 4), and IVA (n = 3) patients. Twenty-four received at least chest radiation therapy (RT) (median dose 3,150 cGy; range: 175-4,650 cGy), one received neck only; 14 (56%) had a history of anthracycline exposure (median dose: 124 mg/m(2) range: 63-200 mg/m2). Compared to CARDIA subjects, mean hsCRP (3.0 mg/L ± 2.0 vs. 1.6 ± 1.9), total cholesterol (194.1 mg/dl ± 33.2 vs. 179.4 ± 32.9), lipoprotein (a) (34.2 mg/dl ± 17.5 vs. 13.8 ± 17.5), and fibrinogen (342.0 mg/dl ± 49.1 vs. 252.6 ± 48.4) were significantly elevated. CECs (2.3 cells/ml ± 1.5 vs. 0.34 ± 1.4) were significantly elevated compared to controls. No difference in VCAM-1 expression (51.1% ± 36.8 vs. 42.3 ± 35.6) was detected.

CONCLUSION

HL survivors exposed to RT have evidence of vascular inflammation, dyslipidemia, and injury suggestive of early atherogenesis.

An observational study of endothelial function in early arthritis

BACKGROUND

Endothelial dysfunction is present in established rheumatoid arthritis, but it is not clear at what stage of the disease this abnormality develops. We set out to determine whether endothelial damage/dysfunction is present in a group of patients with early arthritis (EA) (new onset inflammatory arthritis, EA).

MATERIALS AND METHODS

Eighteen patients with EA, 48 healthy controls and 25 disease controls were recruited. Plasma was obtained for endothelial [von Willebrand factor (vWF) and soluble E-selectin] and angiogenesis markers (vascular endothelial growth factor and its receptor sFlt-1), adhesion molecules (intercellular adhesion molecule 1 and vascular cell adhesion molecule 1) and circulating endothelial cells (CECs, as a marker of endothelial damage). Microvascular endothelial function was assessed using laser Doppler perfusion imaging and macrovascular function using flow-mediated dilatation of the brachial artery.

RESULTS

von Willebrand factor and CECs (both P < 0.05) were significantly elevated in EA suggesting endothelial dysfunction and damage but were unrelated to classical laboratory markers of inflammation C-reactive protein, erythrocyte sedimentation rate or IL6. No other biomarkers was elevated in EA. Microvascular and macrovascular abnormalities were confined to endothelium-independent (smooth muscle cell) responses.

CONCLUSIONS

Endothelial damage/dysfunction is present early in the course of inflammatory arthritis but is not directly related to inflammation markers.

Outcomes of nonstenting percutaneous coronary intervention in patients with rheumatoid arthritis

The aim of the present study was to explore the outcomes of percutaneous coronary intervention (PCI) in patients with rheumatoid arthritis (RA) and coronary heart disease. We identified 25,367 patients from the National Health Insurance Research Database who underwent nonstenting PCI in Taiwan in 2007. Of these patients, 240 had been diagnosed with RA. As a comparison group, we selected 1,200 patients who were matched with the study group by gender and age. We performed conditional logistic regression analysis to compare the outcomes of PCI between the 2 groups. We found no significant differences in the rates of in-hospital mortality (2.5% vs 3.1%, p = 0.628), 90-day readmission for PCI (8.3% vs 7.2%, p = 0.559), or 365-day readmission for PCI (22.5% vs 19.2%, p = 0.236) between the patients with and without RA. Similarly, the conditional logistic regression analyses revealed that patients with RA had no greater adjusted odds of in-hospital mortality (odds ratio 0.94, 95% confidence interval 0.37 to 2.36), 90-day readmission for PCI (odds ratio 1.20, 95% confidence interval 0.37 to 2.36), and 365-day readmission for PCI (odds ratio 1.30, 95% confidence interval 0.92 to 1.83) than the comparison group. In conclusion, our study did not find an increased risk of adverse outcomes among patients with RA after PCI.

Selectins and Associated Adhesion Proteins in Inflammatory disorders

Inflammation is defined as the normal response of living tissue to injury or infection. It is important to emphasize two components of this definition. First, that inflammation is a normal response and, as such, is expected to occur when tissue is damaged. Infact, if injured tissue does not exhibit signs of inflammation this would be considered abnormal and wounds and infections would never heal without inflammation. Secondly, inflammation occurs in living tissue, hence there is need for an adequate blood supply to the tissues in order to exhibit an inflammatory response. The inflammatory response may be triggered by mechanical injury, chemical toxins, and invasion by microorganisms, and hypersensitivity reactions. Three major events occur during the inflammatory response: the blood supply to the affected area is increased substantially, capillary permeability is increased, and leucocytes migrate from the capillary vessels into the surrounding interstitial spaces to the site of inflammation or injury. The inflammatory response represents a complex biological and biochemical process involving cells of the immune system and a plethora of biological mediators. Cell-to-cell communication molecules such as cytokines play an extremely important role in mediating the process of inflammation. Inflammation and platelet activation are critical phenomena in the setting of acute coronary syndromes. An extensive exposition of this complex phenomenon is beyond the scope of this article (Rankin 2004).

Increased number of circulating endothelial cells and plasma markers of endothelial damage in chronic cocaine users

BACKGROUND

Cocaine use has been related with the development of accelerated atherosclerosis and with an increased risk of cardiac and cerebrovascular events, such as myocardial infarction, sudden cardiac death, and ischemic stroke. The underlying mechanisms leading to these complications are not fully understood, although thrombus formation and altered vascular function are prominent findings.

OBJECTIVES

Our aim was to evaluate markers of endothelial dysfunction in chronic cocaine consumers before and after drug withdrawal.

PATIENTS/METHODS

We determined circulating endothelial cells (CECs) and plasma levels of stromal cell-derived factor-1 (SDF-1), monocyte chemotactic protein-1(MCP-1), soluble intracellular adhesion molecule (sICAM), high-sensitivity C reactive protein (hsCRP) and endothelin-1(ET-1), in DSM-IV cocaine addicts at baseline and after one month of cocaine abstinence.

RESULTS

Cocaine users showed a strikingly higher numbers of CEC (62.35 ± 18.4 vs 8.25 ± 13.8 CEC/mL) and significantly elevated plasma levels for all the markers evaluated as compared to the control group. After cocaine withdrawal, patients improved SDF-1, ET-1, hsCRP and sICAM levels. However, CEC number and MCP-1 plasma levels remained significantly elevated. All the results were adjusted for blood levels of cholesterol and triglycerides and for smoking habit.

CONCLUSIONS

Our results demonstrated that chronic cocaine consumption alters several functions of the endothelium towards a pro-thrombotic condition and that some of those functions remain abnormal even after short-term drug withdrawal. These observations support the notion that endothelial dysfunction may play a key role in the pathogenesis of ischemic vascular disease observed in cocaine abusers.

Blood vessels, a potential therapeutic target in rheumatoid arthritis?

New micro-vessels formation within synovium and macro-vessels endothelial damage with atheroma are two major features of rheumatoid arthritis, the former related to the articular involvement of the disease, the latter to its main systemic complication. The similarities between pannus development and solid tumors growth, and the efficacy of anti-angiogenic treatments in oncology, opened the perspective of directly targeting angiogenesis in arthritis. Nevertheless, despite the success of different anti-angiogenic therapeutic strategies in many arthritis experimental models, the application in human disease is still lacking. Recent data suggest that synovial neoangiogenesis and macro-vessels endothelial damage might be two linked phenomena. While synovial angiogenesis seems to be detrimental to endothelial damage repair, even anti-angiogenic treatments might paradoxically aggravate macro-vascular disease, especially in the context of uncontrolled inflammation. These elements induce to further explore the interconnections between inflammation and angiogenesis on one side and between micro- and macro-vascular diseases on the other, in order to establish the proper way to therapeutically target blood vessels in rheumatoid arthritis.

Tourniquet-applied upper limb orthopaedic surgery results in increased inflammation and changes to leukocyte, coagulation and endothelial markers

Purpose

During this pilot clinical study, patients scheduled for elective tourniquet-applied upper limb orthopaedic surgery were recruited to investigate the effects of surgery on various biological markers (n = 10 patients).

Methods

Three venous blood samples were collected from the arm at the ante-cubital fossa, at baseline (pre-operatively), 5 and 15 minutes after reperfusion (post-operatively). Neutrophil and monocyte leukocyte sub-populations were isolated by density gradient centrifugation techniques. Leukocyte activation was investigated by measuring the cell surface expression of CD62L (L-selectin), CD11b (Mac-1) and the intracellular production of hydrogen peroxide (H2O2), via flow cytometry. C-reactive protein (CRP) was measured using a clinical chemistry analyser. Plasma concentrations of protein C and von Willebrand factor (vWF) were measured using enzyme-linked fluorescent assays (ELFA).

Results

Following tourniquet-applied upper limb orthopaedic surgery, there was a decrease in neutrophil CD62L expression (p = 0.001), an increase in CD11b expression and in the intracellular production of H2O2 by neutrophils and monocytes (p<0.05). An increase in CRP concentration (p<0.001), a decrease in protein C concentration (p = 0.004), with a trend towards elevated vWF levels (p = 0.232) were also observed during this time.

Conclusions

Conventionally, patients undergoing orthopaedic surgery have been monitored in the peri-operative period by means of CRP, which is a non-specific marker of inflammation. This test cannot differentiate between inflammation due to current or pre-existing disease processes and the development of ischaemia-reperfusion injury surgery. The findings from this study suggest that markers such as CD11b, protein C and H₂O₂ may provide alternative ways of assessing leukocyte and coagulation activation peri-operatively. It is proposed that by allowing orthopaedic surgeons access to laboratory markers such as CD11b, protein C and H₂O₂, an accurate assessment of the extent of inflammation due to surgery per se could be made.

Enhanced late-outgrowth circulating endothelial progenitor cell levels in rheumatoid arthritis and correlation with disease activity

Introduction

Angiogenesis and vasculogenesis are critical in rheumatoid arthritis (RA) as they could be a key issue for chronic synovitis. Contradictory results have been published regarding circulating endothelial progenitor cells (EPCs) in RA. We herein investigated late outgrowth EPC sub-population using recent recommendations in patients with RA and healthy controls.

Methods

EPCs, defined as Lin-/7AAD-/CD34+/CD133+/VEGFR-2+ cells, were quantified by flow cytometry in peripheral blood mononuclear cells (PBMCs) from 59 RA patients (mean age: 54 ± 15 years, disease duration: 16 ± 11 years) and 36 controls (mean age: 53 ± 19 years) free of cardiovascular events and of cardiovascular risk factors. Concomitantly, late outgrowth endothelial cell colonies derived from culture of PBMCs were analyzed by colony-forming units (CFUs).

Results

RA patients displayed higher circulating EPC counts than controls (median 112 [27 to 588] vs. 60 [5 to 275]) per million Lin- mononuclear cells; P = 0.0007). The number of circulating EPCs positively correlated with disease activity reflected by DAS-28 score (r = 0.43; P = 0.0028) and lower counts were found in RA patients fulfilling remission criteria (P = 0.0069). Furthermore, late outgrowth CFU number was increased in RA patients compared to controls. In RA, there was no association between the number of EPCs and serum markers of inflammation or endothelial injury or synovitis.

Conclusions

Our data, based on a well characterized definition of late outgrowth EPCs, demonstrate enhanced levels in RA and relationship with disease activity. This supports the contribution of vasculogenesis in the inflammatory articular process that occurs in RA by mobilization of EPCs.

Mechanisms and markers of vascular damage in ANCA-associated vasculitis

Much progress has been made in understanding the pathogenesis of anti-neutrophil cytoplasmic antibodies (ANCA)-associated small-vessel vasculitis and interaction between ANCA and micro-vascular endothelial cells are centre stage. The interactions of these key players culminate in respiratory burst of the neutrophil with release of radicals and proteases and subsequent endothelial cell and tissue damage. During the last decade, markers have become available to assess the extent and/or acuity of vascular damage in a clinical setting. First, circulating endothelial cells (CEC) have emerged as reliable surrogate markers of endothelial damage in vasculitis. More recently, endothelial microparticles have been used and appear to reflect damage and activation of the cells. Data on endothelial progenitor cells in vasculitis are sparse but intriguing while a genuine progenitor cell deficiency remains controversial. The severely damaged phenotype of CEC in vasculitis led to the hypothesis that such circulating apoptotic and/or necrotic debris may itself be a mediator of disease and first data from experimental studies have added proof to this assumption. Such effects may well contribute to a pro-inflammatory environment in ANCA-associated small-vessel vasculitis and in vascular disease in general. Here, we review mechanisms and markers of endothelial damage and repair in ANCA-associated vasculitis and put these findings into perspective.