A peptide inhibitor of vascular adhesion protein-1 (VAP-1) blocks leukocyte-endothelium interactions under shear stress

Vascular adhesion protein-1 (VAP-1) is an endothelial adhesion molecule mediating leukocyte interactions with blood vessels during leukocyte extravasation. Molecularly VAP-1 is a cell-surface-expressed ecto-enzyme belonging to the group of semicarbazide-sensitive amine oxidases (SSAO; EC 2.4.6.3), which deaminate primary amines. Here we asked whether peptides displaying a suitable free amine group could be a substrate or inhibitor of SSAO and thus regulate VAP-1-mediated leukocyte adhesion. On the basis of a molecular model of VAP-1, we designed synthetic peptides that fit to the substrate channel of VAP-1. One of these lysine-containing peptides effectively inhibits VAP-1-dependent lymphocyte rolling and firm adhesion to primary endothelial cells under physiologically relevant shear conditions. The same peptide inhibits the SSAO activity of endothelial and recombinant VAP-1 in a selective and long-lasting manner. We also show that all enzymatically active VAP-1 is displayed on the cell surface. Our results suggest that, in addition to soluble amines, specific cell-surface-bound molecules containing free NH(2) groups in a suitable position may modulate the enzymatic activity of SSAO. Moreover, the inhibitory peptide diminishes leukocyte interactions with endothelial cells under conditions of shear, and thus it may be useful to treat inflammatory conditions.     

Function-blocking antibodies to human vascular adhesion protein-1: a potential anti-inflammatory therapy

Human vascular adhesion protein-1 (VAP-1) is a homodimeric 170-kDa sialoglycoprotein that is expressed on the surface of endothelial cells and functions as a semicarbazide-sensitive amine oxidase and as an adhesion molecule. Blockade of VAP-1 has been shown to reduce leukocyte adhesion and transmigration in in vivo and in vitro models, suggesting that VAP-1 is a potential target for anti-inflammatory therapy. In this study we have constructed mouse-human chimeric antibodies by genetic engineering in order to circumvent the potential problems involved in using murine antibodies in man. Our chimeric anti-VAP-1 antibodies, which were designed to lack Fc-dependent effector functions, bound specifically to cell surface-expressed recombinant human VAP-1 and recognized VAP-1 in different cell types in tonsil. Furthermore, the chimeric antibodies prevented leukocyte adhesion and transmigration in vitro and in vivo. Hence, these chimeric antibodies have the potential to be used as a new anti-inflammatory therapy.     

Apparent genotype–phenotype correlation in childhood,adolescent, and adult Chediak‐Higashi syndrome

Chediak‐Higashi syndrome (CHS) is a rare autosomal recessive disorder characterized by severe immunologic defects, reduced pigmentation, bleeding tendency, and progressive neurological dysfunction. Most patients present in early childhood and die unless treated by bone marrow transplantation. About 10–15% of patients exhibit a much milder clinical phenotype and survive to adulthood, but develop progressive and often fatal neurological dysfunction. Very rare patients exhibit an intermediate adolescent CHS phenotype, presenting with severe infections in early childhood, but a milder course by adolescence, with no accelerated phase. Here, we describe the organization and genomic DNA sequence of the CHS1 gene and mutation analysis of 21 unrelated patients with the childhood, adolescent, and adult forms of CHS. In patients with severe childhood CHS, we found only functionally null mutant CHS1 alleles, whereas in patients with the adolescent and adult forms of CHS we also found missense mutant alleles that likely encode CHS1 polypeptides with partial function. Together, these results suggest an allelic genotype–phenotype relationship among the various clinical forms of CHS. © 2002 Wiley‐Liss, Inc.     

Urinary arginine and ornithine in occupational exposure to 2-ethylhexanoic acid

Nine sawmill workers were divided into two groups according to their exposure to 2-ethylhexanoic acid, (EHA), a pesticide which has replaced the older pentochlorophenol. The men with lower exposure excreted 30±10 nmol EHA/mmol creatinine (mean ±SD,n=4) in urine samples taken after the workshift, whereas men with higher exposure excreted 1.8±1.6 mol EHA/mmol creatinine (mean±SD,n=5,p<0.01). The urinary ornithine and arginine concentrations were at the lower exposure 1.4±0.4 and 1.5±0.8 mol/mmol creatinine, respectively (mean±SD,n=4), and they increased significantly (p<0.01) to 4.5±2.5 and 3.2±1.5mol/mmol (mean±SD,n=5), respectively, at the higher exposure. This might have been caused by the inhibitory effect of EHA on urea synthesis which was partially compensated for by elevated arginine and ornithine concentrations to drive the urea cycle more efficiently.     

Determinants for preventive oral health care need among community‐dwelling older people: a population‐based study

The aim was to study the determinants of preventive oral health care need among community‐dwelling old people. The study population consisted of 165 participants, a subpopulation in the Geriatric Multidisciplinary Strategy for Good Care of Elderly People (GeMS) study. Fifty‐five percent of the edentate participants with full dentures and 82% of the dentate had a need for preventive oral health care. In the total study population, the need for preventive care was associated with co‐morbidity (measured by means of the Modified Functional Co‐morbidity Index) odds ratios (OR) 1.2 (confidence intervals [CI] 1.0–1.5), being pre‐frail or frail, OR 2.5 (CI 1.2–5.1), presence of natural teeth, OR 4.8 (CI 2.2–10.4), and among dentate participants, the use of a removable partial denture, OR 12.8 (CI 1.4–114.4). Primary care clinicians should be aware of the high need for preventive care and the importance of nonoral conditions as determinants of preventive oral health care need.     

A Case of Abnormal Lymphatic-Like Differentiation and Endothelial Progenitor Cell Activation in Neovascularization Associated with Hemi-Retinal Vein Occlusion

PurposePathological vascular differentiation in retinal vein occlusion (RVO)-related neovessel formation remains poorly characterized. The role of intraocular lymphatic-like differentiation or endothelial progenitor cell activity has not been studied in this disease.MethodsVitrectomy was performed in an eye with hemi-RVO; the neovessel membrane located at the optic nerve head was removed and subjected to immunohistochemistry. Characterization of the neovascular tissue was performed using hematoxylin and eosin, α-smooth muscle actin, and the pan-endothelial cell (EC) adhesion molecule CD31. The expression of lymphatic EC markers was studied by lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1), podoplanin (PDPN), and prospero-related homeobox protein 1 (Prox-1). Potential vascular stem/progenitor cells were identified by active cellular proliferation (Ki67) and expression of the stem cell marker CD117.ResultsThe specimen contained blood vessels lined by ECs and surrounded by pericytes. Immunoreactivity for LYVE-1 and Prox-1 was detected, with Prox-1 being more widely expressed in the active Ki67-positive lumen-lining cells. PDPN expression was instead found in the cells residing in the extravascular tissue. Expression of the stem cell markers CD117 and Ki67 suggested vascular endothelial progenitor cell activity.ConclusionsIntraocular lymphatic-like differentiation coupled with progenitor cell activation may be involved in the pathology of neovessel formation in ischemia-induced human hemi-RVO.Key Words: Hemi-retinal vein occlusion, Endothelial progenitor cell, Platelet endothelial cell adhesion molecule 1, Podoplanin, Prospero-related homeobox gene 1, Lymphatic endothelial cell, Lymphatic vessel endothelial hyaluronan receptor 1, Immunohistochemistry, Proliferative diabetic retinopathy, Vascular endothelial stem cell     

Origins of serum semicarbazide-sensitive amine oxidase

Semicarbazide-sensitive amine oxidases (SSAO) are enzymes that are capable of deaminating primary amines to produce aldehyde, ammonia, and hydrogen peroxide. This activity has been associated with vascular adhesion protein-1 (VAP-1) and is found in the serum, endothelium, adipose, and smooth muscle of mammals. Circulating SSAO activity is increased in congestive heart failure, diabetes, and inflammatory liver diseases. To investigate the origin of circulating SSAO activity, two transgenic mouse models were created with full-length human VAP-1 (hVAP-1) expressed on either endothelial (mTIEhVAP-1) or adipose tissues (aP2hVAP-1), with tie-1 and adipocyte P2 promoters, respectively. Under normal conditions a circulating form of hVAP-1 was found at high levels in the serum of mice with endothelium-specific expression and at low levels in the serum of mice with adipose specific expression. The level of circulating hVAP-1 in the transgenic mice varied with gender, transgene zygosity, diabetes, and fasting. Serum SSAO activity was absent from VAP-1 knockout mice and endothelial cell-specific expression of human VAP-1 restored SSAO activity to the serum of VAP-1 knockout mice. Together, these experiments show that in the mouse VAP-1 is the only source of serum SSAO, that under physiological conditions vascular endothelial cells can be a major source of circulating VAP-1 protein and SSAO, and that serum VAP-1 can originate from both endothelial cells and adipocytes during experimental diabetes. An increased endothelial cell capacity for lymphocyte binding and altered expression of redox-sensitive proteins was also associated with the mTIEhVAP-1 transgene.     

Effect of soybean phytoestrogen intake on low density lipoprotein oxidation resistance

The oxidation of low density lipoproteins (LDLs) is thought to take place in the arterial intima when the particles have become isolated from circulating water-soluble antioxidants. We hypothesized that isoflavonoid antioxidants derived from soy could be incorporated into lipoproteins and possibly could protect them against oxidation, which is regarded as atherogenic. Six healthy volunteers received 3 soy bars [containing the isoflavonoid antioxidants genistein (12 mg) and daidzein (7 mg)] daily for 2 weeks. LDLs were isolated from blood drawn at the the end of a 2-week dietary baseline period, after 2 weeks on soy, and after discontinuation of soy. Large increases in plasma isoflavonoid levels occurred during soy feeding, but only minute amounts were stably associated with lipoproteins (less than 1% of plasma isoflavonoids in the LDL fraction). The LDLs were subjected to copper-mediated oxidation in vitro. Compared with off soy values, lag phases of LDL oxidation curves were prolonged by a mean of 20 min (P < 0.02) during soy intake, indicating a reduced susceptibility to oxidation. The results suggest that intake of soy-derived antioxidants, such as genistein and daidzein, may provide protection against oxidative modification of LDL. As only very small amounts of these substances were detected in purified LDL, modified LDL particles may have been produced in vivo by circulating isoflavonoids promoting resistance to oxidation ex vivo.     

Functional impairment in spondyloarthropathy and fibromyalgia

OBJECTIVE: To compare the functional ability of patients with spondyloarthropathy (SpA) and fibromyalgia (FM) using the Bath Ankylosing Spondylitis Functional Index (BASFI), the Dougados Functional Index (DFI), and and the Health Assessment Questionnaire for Spondyloarthropathy (HAQ-S), to establish whether these indicators can differentiate between these patient groups, and to ascertain how well the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) functions in patients with FM. METHODS: Twenty-four patients with SpA and 70 with FM, all female, filled in 4 self-administered questionnaires: BASFI, DFI, HAQ-S, and the BASDAI; results were compared between the 2 groups. RESULTS: The decline in functional ability was similar in patients with SpA and FM when assessed by BASFI, but slightly greater in the SpA group when assessed by DFI and HAQ-S. BASDAI was significantly (p = 0.018) greater in the FM group. CONCLUSION: An almost similar functional decline was observed in both SpA and FM patients when measured by the indices developed for patients with AS and SpA. The specificity of BASDAI in measuring disease activity in SpA was poor, as disease activity in FM was rated higher than in SpA.