Comparison of cell adhesion molecule expression in cutaneous leucocytoclastic and lymphocytic vasculitis

Sequential Increase in Complement Factor I, iC3b, and Cells Expressing CD11b or CD14 in Cutaneous Vasculitis

Mast cells contribute to the pathogenesis of cutaneous vasculitis through complement C3 that is cleaved to C3b and then to iC3b by complement factor I. The receptor of iC3b, CD11b, is expressed on neutrophils and monocytes and CD14 on monocytes. Their role in vasculitis is obscure. In this study, frozen skin biopsies from the nonlesional skin, initial petechial lesion, and palpable purpura lesion from 10 patients with immunocomplex-mediated small vessel vasculitis were studied immunohistochemically for complement factor I, iC3b, CD11b, and CD14. Peripheral blood mononuclear cells from 5 healthy subjects were used to study cell migration and cytokine secretion. Already, the nonlesional skin revealed marked immunostaining of complement factor I, iC3b, CD11b, and CD14, and their expression increased sequentially in initial petechial and palpable purpura lesions. Mast cell C3c correlated to iC3b, and both of them correlated to CD11b⁺ and CD14⁺ cells, in the nonlesional skin. The stimulation of mononuclear cells with 0.01-0.1 μg/ml iC3b induced cell migration in the transwell assay. C3a stimulated slightly interleukin-8 secretion, whereas 1 μg/ml iC3b inhibited it slightly, in 4/5 subjects. In conclusion, the C3-C3b-iC3b axis is activated already in the early vasculitis lesion leading to progressive accumulation of CD11b⁺ and CD14⁺ cells.

Endothelial Activation Markers in Polytransfused Children with Beta Thalassemia: Study from a Tertiary Care Centre in India

Beta thalassemia major is associated with a subclinical hypercoagulable state. Endothelial activation markers like soluble Intercellular adhesion molecule (sICAM-1) and E-selectin have been implicated in the pathogenesis of endothelial dysfunction and hemostatic alterations. In this study we aimed to study serum levels of sICAM-1 and E-selectin in polytransfused children with β thalassemia major and their association with serum ferritin and D-dimer levels. Sixty-two polytransfused β-thalassemia major children aged between 5 and 17 years and 26 age and gender matched healthy controls were enrolled in the study. Complete blood count with peripheral smear, liver function tests, serum ferritin, coagulation tests [PT, APTT, D-dimer] and endothelial activation marker tests [ICAM-1 and E-selectin] were performed. PT, APTT and D-dimer levels were significantly higher in beta-thalassemia major patients than in control group (p = 0.003, p < 0.001, p < 0.001 respectively). Mean ICAM-1 and E-selectin levels were 731.34 ± 343.97 ng/ml and 111.75 ± 40.13 ng/ml respectively which were significantly higher than control group (p < 0.001, p < 0.001 respectively). No significant correlation of ICAM-1 and E-selectin was observed with serum ferritin, PT, APTT and D-dimer levels. The findings of the present study suggest that there is ongoing subclinical activation of coagulation cascade and fibrinolytic system in these patients. Endothelial activation markers may be used as early indicators of endothelial dysfunction to assess the thrombotic complications in beta thalassemia.

Diagnosis and management of cutaneous vasculitis in children

Cutaneous vasculitis in children is rare. Causes of cutaneous vasculitis are varied and are typically differentiated by the affected vessel size. A skin biopsy remains the gold standard for diagnosis but other causes for vasculitis, including systemic conditions, should be considered. This article discusses the childhood conditions commonly presenting with cutaneous vasculitis (leukocytoclastic vasculitis, cutaneous polyarteritis nodosa), biopsy recommendations and findings, and management and potential differential diagnoses, and includes a brief summary of other diseases that may include cutaneous symptoms as a constellation of other systemic findings.

Biomarkers of endothelial cell activation serve as potential surrogate markers for drug-induced vascular injury

Drug-induced vascular injury (DIVI) is a nonclinical finding that often confounds the toxicological evaluation of investigational drugs, but there is an absence of qualified biomarkers that can be used to detect and monitor its appearance in animals and patients during drug development and clinical use. It is well known that endothelial cell (EC) activation plays a key role in the expression and evolution of DIVI, and the various immunological and inflammatory factors involved in its expression may serve as potential biomarker candidates. Activated ECs change their morphology and gene expression, generating endothelial adhesion molecules, pro-coagulant molecules, cytokines, chemokines, vasodilators, nitric oxide, and acute-phase reactants. This review provides a brief historical background of EC activation and the search for biomarkers of early EC activation for monitoring DIVI. At present, no biomarkers of EC activation have been qualified to predict DIVI in the nonclinical or clinical context, and a robust pathologic foundation for their use is still lacking. We propose three categories of EC activation biomarkers: recommended surrogate markers, potentially useful markers, and emerging candidate markers. This review alerts pharmaceutical companies, research institutions, and regulatory agencies to the continuing need for reliable biomarkers of EC activation in drug development.

Cutaneous vasculitis: diagnosis and management

Vasculitis is histologically defined as inflammatory cell infiltration and destruction of blood vessels. Vasculitis is classified as primary (idiopathic, eg, cutaneous leukocytoclastic angiitis, Wegener's granulomatosis) or secondary, a manifestation of connective tissue diseases, infections, adverse drug eruptions, or a paraneoplastic phenomenon. Cutaneous vasculitis, manifested as urticaria, purpura, hemorrhagic vesicles, ulcers, nodules, livedo, infarcts, or digital gangrene, is a frequent and often significant component of many systemic vasculitic syndromes such as lupus or rheumatoid vasculitis and antineutrophil cytoplasmic antibody-associated primary vasculitic syndromes such as Churg-Strauss syndrome. In most instances, cutaneous vasculitis represents a self-limited, single-episode phenomenon, the treatment of which consists of general measures such as leg elevation, warming, avoidance of standing, cold temperatures and tight fitting clothing, and therapy with antihistamines, aspirin, or nonsteroidal anti-inflammatory drugs. More extensive therapy is indicated for symptomatic, recurrent, extensive, and persistent skin disease or coexistence of systemic disease. For mild recurrent or persistent disease, colchicine and dapsone are first-choice agents. Severe cutaneous and systemic disease requires more potent immunosuppression (prednisone plus azathioprine, methotrexate, cyclophosphamide, cyclosporine, or mycophenolate mofetil). In cases of refractory vasculitis, plasmapheresis and intravenous immunoglobulin are viable considerations. The new biologic therapies that work via cytokine blockade or lymphocyte depletion such as tumor alpha inhibitor infliximab and the anti-B-cell antibody rituximab, respectively, are showing benefit in certain settings such as Wegener's granulomatosis, antineutrophil cytoplasmic antibody-associated vasculitis, Behçet's disease, and cryoglobulinemic vasculitis.

Cutaneous Vasculitis Update: Diagnostic Criteria, Classification, Epidemiology, Etiology, Pathogenesis, Evaluation and Prognosis

Vasculitis, inflammation of the vessel wall, can result in mural destruction with hemorrhage, aneurysm formation, and infarction, or intimal-medial hyperplasia and subsequent stenosis leading to tissue ischemia. The skin, in part due to its large vascular bed, exposure to cold temperatures, and frequent presence of stasis, is involved in many distinct as well as un-named vasculitic syndromes that vary from localized and self-limited to generalized and life-threatening with multi-organ disease. To exclude mimics of vasculitis, diagnosis of cutaneous vasculitis requires biopsy confirmation where its acute signs (fibrinoid necrosis), chronic signs (endarteritis obliterans), or past signs (acellular scar of healed arteritis) must be recognized and presence of extravascular findings such as patterned fibrosis or collagenolytic granulomas noted. Although vasculitis can be classified by etiology, many cases have no identifiable cause, and a single etiologic agent can elicit several distinct clinicopathologic expressions of vasculitis. Therefore, the classification of cutaneous vasculitis is best approached morphologically by determining vessel size and principal inflammatory response. These histologic patterns roughly correlate with pathogenic mechanisms that, when coupled with direct immunofluorescent examination, anti-neutrophil cytoplasmic antibody (ANCA) status, and findings from work-up for systemic disease, allow for specific diagnosis, and ultimately, more effective therapy. Herein, we review cutaneous vasculitis focusing on diagnostic criteria, classification, epidemiology, etiology, pathogenesis, and evaluation of the cutaneous vasculitis patient.

Increased levels of circulating adhesion molecules in neonates with congenital diaphragmatic hernia complicated by persistent pulmonary hypertension

The aim of this study was to determine circulating levels of adhesion molecules in serum from patients with congenital diaphragmatic hernia (CDH) to investigate the relationship between soluble ICAM-1, ELAM-1, and VCAM-1 liberated by activated vascular endothelium and the development of persistent pulmonary hypertension (PPH) in patients with CDH. We measured serum levels of ICAM-1, ELAM-1, and VCAM-1 in 20 high-risk neonates with CDH at the time of diagnosis (11 with PPH and 9 without PPH) and 7 age-matched controls using ELISA system. We further examined the lungs of 5 patients with CDH complicated by PPH who died during resuscitation and stabilization, and three control lung specimens for the expression of adhesion molecules using immunohistochemistry. The mean serum ICAM-1 levels in CDH patients with PPH (227.0+/-98.9 ng/ml) were increased compared with levels in CDH patients without PPH (140.29+/-37.4 ng/ml; p<0.05) and controls (130.0+/-23.8 ng/ml; p<0.05). Mean serum ELAM-1 levels in CDH patients with PPH (116.5+/-19.2 ng/ml) were significantly increased compared with levels in CDH patients without PPH (79.3+/-27.9 ng/ml; p<0.01) and controls (58.4+/-14.5 ng/ml; p<0.001). Mean serum VCAM-1 levels in CDH patients with PPH (1596.9+/-460.4 ng/ml) were significantly higher compared with levels in CDH patients without PPH (1069.3+/-444.6 ng/ml; p<0.01) and controls (838.0+/-171.2 ng/ml; p<0.001). But serum adhesion molecule levels in CDH patients without PPH were no different from controls statistically. Pulmonary vascular endothelial cells from CDH lung with PPH had strong expression of adhesion molecules compared with controls. Up-regulated expression of adhesion molecules on the endothelium of pulmonary vessels and high circulating levels of adhesion molecules in CDH patients with PPH suggest that adhesion molecules may play a role in the development of PPH in CDH.

Expression of ICAM-1, VCAM-1, E-selectin and TNF-alpha on the endothelium of femoral and iliac arteries in thromboangiitis obliterans

Immunohistochemical light and electron microscopical analysis of surgical biopsies obtained from femoral and iliac arteries of patients with thromboangiitis obliterans (TAO) were performed to investigate the presence of tumour necrosis factor-alpha (TNF-alpha) and expression of the endothelial cell adhesion molecules intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and E-selectin. Expression of ICAM-1, VCAM-1 and E-selectin was increased on endothelium and some inflammatory cells in the thickened intima in all TAO patients. Ultrastructural immunohistochemistry revealed contacts between mononuclear blood cells and ICAM-1-, and E-selectin-positive endothelial cells. These endothelial cells showed morphological signs of activation. The present data indicate that endothelial cells are activated in TAO and that vascular lesions are associated with TNF-alpha secretion by tissue-infiltrating inflammatory cells, ICAM-1-, VCAM-1- and E-selectin expression on endothelial cells and leukocyte adhesion via their ligands. The preferential expression of inducible adhesion molecules in microvessels and mononuclear inflammatory cells suggests that angiogenesis contributes to the persistence of the inflammatory process in TAO.

Anti-endothelial cell antibodies from patients with thrombotic thrombocytopenic purpura specifically activate small vessel endothelial cells

Thrombotic thrombocytopenic purpura (TTP) is an uncommon disease of an unknown etiology, characterized by consumptive thrombocytopenia, microangiopathic hemolytic anemia, fever and acute thrombotic complications, especially within the cerebral circulation. Although anti-endothelial cell antibodies (AECA) have occasionally been shown to be present in TTP, their role in the pathogenesis of the disease has never been ascertained. In the current study we demonstrated the pathogenic activity of affinity-purified anti-endothelial cell F(ab)2 antibodies (AECA/TTP) from four consecutive patients with active TTP. These AECA/TTP bound to and activated only microvascular endothelial cells (EC) and not large vessel EC. The specificity of AECA/TTP binding to microvascular EC was confirmed by competition assay employing membranes derived from small and large vessels EC. Activation included enhanced IL-6 and von Willebrand factor release from the EC followed by increased expression of adhesion molecules P-selectin, E-selectin and vascular cell adhesion molecule-1 on the EC, as evaluated by ELISA. Increased expression of adhesion molecules was followed by an increase in monocyte adhesion to EC. The level of soluble thrombomodulin (TM) also increased in the culture medium of activated microvascular EC upon exposure to AECA/TTP antibodies and was directly correlated to a decrease in cell-associated TM. Our data suggest that AECA/TTP directed against microvascular EC could play a pathogenic role in the development of endothelial injury in TTP that leads to thrombosis.

Cytokines and adhesion molecules in the pathogenesis of vasculitis

Upregulated adhesion molecule and cytokine expression on endothelial cells and infiltrating inflammatory cells occur in most vasculitis syndromes. These observations suggest that vasculitis is associated with pathologic activation of normal immune cell cytokine cascades. Abnormal expression of adhesion molecules and cytokines in vascular endothelium is a manifestation of endothelial dysfunction that can be triggered by a variety of stimuli, including infectious agents, immune complexes, and antiendothelial cell antibodies. Dysregulated adhesion molecule expression, uncontrolled inflammation, thrombosis, and vessel occlusion lead to the clinical manifestations of vasculitis.

Defining lymphocytic vasculitis

Vasculitis can be defined as vascular inflammation which is usually immune mediated, leading to structural and functional damage to the vessel wall. Our concept of vasculitis has been built around the events surrounding immune-complex-triggered leukocytoclastic vasculitis, while the role of lymphocyte mediated vasculitis remains largely undefined. This may be due to maintaining a stereotypic image of lymphocytic vasculitis as one associated with vascular necrosis, fibrin deposition and haemorrhage and merely substituting lymphocytes for neutrophils. Our understanding of lymphocytic vasculitis may be advanced by identifying the clinical settings in which such reactions may occur, such as autoimmune skin diseases sharing features with graft vs host disease, as well as recognizing that lymphocyte mediated inflammation may lead to a morphologically distinct group of vasculitides, apart from those associated with angiodestruction. Lymphocytic endovasculitis, lymphocytic lichenoid vasculitis and granulomatous vasculitis are potential examples of lymphocytic vasculitis that differ from the histological pattern seen in association with immune complex leukocytoclastic vasculitis. Ultimately, the proof that these vasculitides are examples of lymphocytic vasculitis will rest on new techniques emerging in molecular pathology that have the capacity of analysing the immunological events beyond the current limitations posed by routine histopathology.

Cell adhesion molecules in the development of inflammatory infiltrates in giant cell arteritis: inflammation-induced angiogenesis as the preferential site of leukocyte-endothelial cell interactions

OBJECTIVE

To investigate the expression pattern of adhesion molecules involved in leukocyte-endothelial cell interactions in giant cell arteritis (GCA).

METHODS

Immunohistochemical analysis was performed on frozen temporal artery sections from 32 patients with biopsy-proven GCA and from 12 control patients with other diseases. Adhesion molecules identified were intercellular adhesion molecule 1 (ICAM-1), ICAM-2, ICAM-3, vascular cell adhesion molecule 1 (VCAM-1), platelet endothelial cell adhesion molecule 1 (PECAM-1), E-selectin, P-selectin, L-selectin, lymphocyte function-associated antigen 1 (LFA-1), very late activation antigen 4 (VLA-4), Mac-1 (CD18/CD11b), and gp 150,95 (CD18/CD11c). Clinical and biochemical parameters of inflammation in the patients, as well as the duration of previous corticosteroid treatment, were prospectively recorded.

RESULTS

Constitutive (PECAM-1, ICAM-1, ICAM-2, and P-selectin) and inducible (E-selectin and VCAM-1) endothelial adhesion molecules for leukocytes were mainly expressed by adventitial microvessels and neovessels within inflammatory infiltrates. Concurrent analysis of leukocyte receptors indicated a preferential use of VLA-4/VCAM-1 and LFA-1/ICAM-1 at the adventitia and Mac-1/ICAM-1 at the intima-media junction. The intensity of inducible endothelial adhesion molecule expression (E-selectin and VCAM-1) correlated with the intensity of the systemic inflammatory response. Previous corticosteroid treatment reduced, but did not completely abrogate, the expression of the inducible endothelial adhesion molecules E-selectin and VCAM-1.

CONCLUSION

Inflammation-induced angiogenesis is the main site of leukocyte-endothelial cell interactions leading to the development of inflammatory infiltrates in GCA. The distribution of leukocyte-endothelial cell ligand pairs suggests a heterogeneity in leukocyte-endothelial cell interactions used by different functional cell subsets at distinct areas of the temporal artery.

Monoclonal anti-endothelial cell antibodies from a patient with Takayasu arteritis activate endothelial cells from large vessels

OBJECTIVE

To create monoclonal anti-endothelial cell antibodies (mAECA) from a patient with Takayasu arteritis to evaluate their ability to activate human umbilical vein endothelial cells (HUVEC), and to characterize the mechanism of EC activation.

METHODS

A panel of mAECA was generated from peripheral blood lymphocytes of a patient with Takayasu arteritis, using Epstein-Barr virus transformation. Activity against macrovascular EC (HUVEC) and microvascular EC (human bone marrow EC immortalized by SV40) antigens was detected by enzyme-linked immunosorbent assay. Inhibition studies were used to select the monoclonal antibodies (mAECA) which share the same EC epitope binding specificity as the total IgG-AECA from the Takayasu arteritis patient. The binding of the mAECA to human aortic EC was studied by immunohistochemistry. The secretion levels of interleukin-6 (IL-6) and von Willebrand factor (vWF) were determined, to serve as markers for EC activation. The activated EC were examined for the adherence of a monocytic cell line (U937), as well as for expression of vascular cell adhesion molecule 1, intercellular adhesion molecule 1, and E-selectin. In addition, nuclear extracts of the mAECA-treated EC were analyzed for the induction of translocation of nuclear factor kappaB (NF-kappaB), using a specific NF-kappaB oligoprobe in an electrophoretic mobility shift assay.

RESULTS

Six mAECA were selected, the mixture of which produced 100% inhibition of binding of the original IgG (from the patient with Takayasu arteritis) to HUVEC. All mAECA possessed high activity against macrovascular EC, but none had significant antimicrovascular EC activity. The mAECA, but not normal human IgG, had anti-human aortic EC activity. Four of the 6 mAECA activated EC, manifested by increased IL-6 and vWF secretion. The 4 mAECA induced EC expression of adhesion molecules and increased adhesion of U937 monocytic cells to EC. In addition, these mAECA stimulated the nuclear translocation of the NF-kappaB transcription factor.

CONCLUSION

Our findings suggest that AECA may directly stimulate EC in Takayasu arteritis through elevation of adhesion molecule expression associated with NF-kappaB activation and adhesion of monocytes, and may therefore play a pathogenic role in the development of the vasculopathy in Takayasu arteritis.

Characterization of an apparently conserved epitope in E- and P-selectin identified by dual-specific monoclonal antibodies

E- and P-selectin recognize a wide and overlapping range of oligosaccharide ligands including sialyl-Lewis X (sLeX) through their highly homologous C-type lectin domains. We report that an epitope apparently conserved between E- and P-selectin is functionally involved in ligand recognition although distantly located from the conventional carbohydrate binding site. We found that a previously established anti-E-selectin monoclonal antibody (mAb), 1.2B6, is cross-reactive with P-selectin, and that the 1.2B6 epitope is in the C-type lectin domain and identical to or overlapping with an epitope recognized by other independently established anti-E- and P-selectin dual-specific mAb. The epitope has been mapped by others to a region distant from the previously identified carbohydrate binding site of E-selectin in its three-dimensional structure. Nevertheless, it is of note that all dual-specific mAb, including 1.2B6, inhibited E- or P-selectin-mediated cell adhesion and also binding to sLeX. Engagement of the apparently conserved epitope by the dual-specific mAb may lead to inhibition of the ligand binding ability of E- and P-selectin by a previously uncharacterized mechanism(s) rather than by direct inhibition of sLeX binding to the hitherto identified ligand binding site.

T-lymphocytes from individuals with filarial inflammatory disease have increased transendothelial migration in vitro

The in vitro transendothelial migration of circulating filarial antigen-specific T-cells was examined in Wuchereria banerofti infection. Circulating T-cells from individuals with filaria-induced lymphatic pathology (LP) had significantly greater migration through unstimulated HUVEC monolayers than did T-cells from asymptomatic infected (MF) individuals (P = 0.04). In contrast to the MF individuals where no effect was seen, transendothelial migration of 48-hr filarial antigen stimulated T-cells from LP individuals was significantly (P = 0.01) greater than migration of 48-hr media-stimulated T-cells. In six of seven patients examined, inhibition of the VLA-4/VCAM-1 pathway resulted in greater than 50% inhibition of transendothelial migration of T-cells.

Beneficial effects of amlodipine in a murine model of congestive heart failure induced by viral myocarditis. A possible mechanism through inhibition of nitric oxide production

BACKGROUND

Although calcium channel blockers have not been shown to be beneficial for the treatment of patients with heart failure, a recent clinical trial demonstrated a favorable effect of amlodipine on the survival of patients with heart failure resulting from nonischemic dilated cardiomyopathy. We investigated the effects of amlodipine on a murine model of congestive heart failure induced by the M variant of encephalomyocarditis virus (EMCV).

METHODS AND RESULTS

Four-week-old male DBA/2 mice were inoculated with EMCV and administered amlodipine, diltiazem, or vehicle PO for 2 weeks. The heart weight-to-body weight ratio and the histopathological grades of myocardial lesions were significantly lower and survival was significantly increased in the amlodipine-treated group (P < .01, P < .05, and P < .05, respectively) than in the control group. In vitro, amlodipine added to murine J774A.1 macrophages concomitant with EMCV inhibited nitrite formation in a concentration-dependent manner, but diltiazem did not. Furthermore, NG-monomethyl-L-arginine, an inhibitor of NO synthesis, decreased myocardial lesions significantly in this murine model. Immunohistochemistry revealed that the number of cells stained with antibody against an inducible NO synthase decreased significantly in the amlodipine-treated group compared with that in the control group (P < .01).

CONCLUSIONS

Amlodipine appears to have a protective effect against myocardial injury in this animal model of congestive heart failure. The therapeutic effect of amlodipine may be in part resulting from inhibition of overproduction of NO.