Bone microstructure and volumetric bone mineral density in patients with hyperuricemia with and without psoriasis.

We analyzed volumetric bone mineral density (vBMD) and bone microstructure using HR-pQCT in subjects with normouricemia (NU) and subjects with hyperuricemia (HU) with and without psoriasis (PSO). HU was associated with higher cortical vBMD and thickness. Differences in average and trabecular vBMD were found between patients with PSO + HU and NU. INTRODUCTION: Hyperuricemia (HU) and gout are co-conditions of psoriasis and psoriatic arthritis. Current data suggest a positive association between HU and areal bone mineral density (BMD) and a negative influence of psoriasis on local bone, even in the absence of arthritis. However, the influence of the combination of HU and psoriasis on bone is still unclear. The aim of this study was to assess the impact of HU with and without psoriasis on bone microstructure and volumetric BMD (vBMD). METHODS: Healthy individuals with uric acid levels within the normal range (NU), with hyperuricemia (HU), patients with hyperuricemia and psoriasis (PSO + HU), and patients with uric acid within the normal range and psoriasis (PSO + NU) were included in our study. Psoriasis patients had no current or past symptoms of arthritis. Average, trabecular, and cortical vBMD (mgHA/cm3); trabecular number (Tb.N, 1/mm) and thickness (Tb.Th, mm); inhomogeneity of the network (1/N.SD, mm); and cortical thickness (Ct.Th., mm) were carried out at the ultradistal radius using high-resolution peripheral quantitative computed tomography. In addition, bone turnover markers such as DKK-1, sclerostin, and P1NP were analyzed. RESULTS: In total, 130 individuals were included (44 NU participants (34% female), 50 HU (24%), 16 PSO + HU (6%), 20 PSO + NU (60%)). Subjects were aged: NU 54.5 (42.8, 62.1), HU 57.5 (18.6, 65.1), PSO + HU 52.0 (42.3, 57.8), and PSO + NU 42.5 (34.8, 56.8), respectively. After adjusting for age, sex, BMI, and diabetes, patients in the HU group revealed significantly higher values of cortical vBMD (p < 0.001) as well as cortical thickness (p = 0.04) compared to the NU group. PSO + NU showed no differences to NU, but PSO + HU demonstrated both lower average (p = 0.03) and trabecular vBMD (p = 0.02). P1NP was associated with average, cortical, and trabecular vBMD as well as cortical thickness while sclerostin levels were related to trabecular vBMD. CONCLUSION: Hyperuricemia in otherwise healthy subjects was associated with a better cortical vBMD and higher cortical thickness. However, patients with both psoriasis and hyperuricemia revealed a lower vBMD.

Antithrombotic triple therapy and coagulation activation at the site of thrombus formation: a randomized trial in healthy subjects.

BACKGROUND: Patients with acute coronary syndrome and concomitant atrial fibrillation may require antithrombotic triple therapy but clinical evidence of safety and efficacy is poor. We have therefore studied the combination of different antithrombotic medicines for coagulation activation in an in vivo model in the skin microvasculature. METHODS AND RESULTS: Platelet activation (ß-thromboglobulin [ß-TG]) and thrombin generation (prothrombin fragment 1 + 2 [F1+2 ], thrombin-antithrombin complex [TAT]) were studied in an open-label, randomized, parallel group trial in 60 healthy male subjects (n = 20 per group) who received ticagrelor and acetylsalicylic acid (ASA) in combination with dabigatran (150 mg bid), rivaroxaban (20 mg od) or phenprocoumon (INR 2.0-3.0). Coagulation biomarkers in shed blood were assessed at 3 h after monotherapy with the medicines under study, at 3 h after triple therapy dosing and at steady state trough conditions. Single doses of ticagrelor, dabigatran or rivaroxaban caused comparable decreases in shed blood ß-TG and were more pronounced than phenprocoumon at an INR of 2.0-3.0. In contrast, thrombin generation was more affected by rivaroxaban and phenprocoumon than by dabigatran. During triple therapy a similarly sustained inhibition of platelet activation and thrombin generation with a maximum decrease of ß-TG, F1+2 and TAT at 3 h post-dosing was noted, which remained below pre-dose levels at trough steady state. CONCLUSION: A triple therapy at steady state with ticagrelor plus ASA in combination with dabigatran or rivaroxaban is as effective as a combination with phenprocoumon for platelet activation and thrombin generation in vivo.

The uremic toxin indoxyl sulfate acts as a pro- or antioxidant on LDL oxidation.

Uremic toxins have been shown to play a role in chronic kidney disease (CKD) associated oxidative stress. Oxidative stress and inflammation have been associated with increased risk of cardiovascular disease in uraemia. The oxidative modification of LDL may play a role in early atherogenesis. Enhanced LDL oxidation has been found in uremic patients which may account for accelerated atherosclerosis observed in CKD. The uremic toxin indoxyl sulfate (IS) has been reported to exert oxidative and antioxidative activity. Thus, in the present study we have investigated the influence of IS on the atherogenic modifications of LDL exposed in vitro to different oxidising systems. The transition metal ion (Cu(2+)) and hemin/H2O2 induced lipid oxidation reactions monitored by conjugated diene formation, were inhibited by the presence of IS, which points to possible antioxidant effects by this uremic toxin. A protective effect of IS on LDL apoprotein modification by the exposure to the product of the myeloperoxidase/H2O2/Cl(-) system HOCl, was also observed as estimated by protein carbonyl formation. In contrast, a marked increase in conjugated dienes and lipid hydroperoxides was observed when lipid oxidation was initiated by the free radical generator AAPH in presence of IS. The GC-MS analysis revealed the formation of indole-2,3-dione and 6,12-dihydro-6,12-dioxo-indolo[2,1-b]quinazoline (tryptanthrin) in IS/AAPH reaction. A scheme for the generation of tryptanthrin from IS via indoxyl radicals is proposed, which may facilitate LDL lipid oxidation. Our observations add further insight in the Janus-faced properties of this important uremic toxin.

Effect of edoxaban on markers of coagulation in venous and shed blood compared with fondaparinux.

Edoxaban, an oral direct factor Xa (FXa) inhibitor, is in phase III clinical development for stroke prevention in atrial fibrillation and treatment of venous thromboembolism. The shed blood model allows for study of activated coagulation at a site of standardised tissue injury due to local release of tissue factor. The objective of this study was to evaluate the effect of three doses of edoxaban on markers of coagulation in shed and venous blood versus placebo and a standard prophylactic dose of fondaparinux. A total of 100 healthy male subjects were randomised to receive single doses of one of five treatments: subcutaneously administered fondaparinux 2.5 mg; orally administered edoxaban 30, 60, or 120 mg; or placebo. The primary objective was measurement of blood coagulation markers prothrombin fragment 1+2 (F1+2) and thrombin-antithrombin (TAT) complex, and platelet activation marker ß-thromboglobulin (ß-TG), in venous and shed blood. Secondary objectives included pharmacokinetics, shed blood volume, and safety of edoxaban. Single doses of edoxaban caused rapid and significant decreases of F1+2, TAT, and ß-TG in the shed blood model, indicating inhibition of thrombin generation and platelet activation. Inhibition was significantly less for fondaparinux versus edoxaban. Baseline-corrected F1+2, TAT, and ß-TG values demonstrated sustained inhibition up to 24 hours for shed blood in the edoxaban groups but no significant inhibition in venous blood. Overall, edoxaban treatments were well tolerated. In conclusion, single oral doses of edoxaban 30, 60, or 120 mg caused rapid and sustained inhibition of coagulation up to 24 hours in the shed blood model.

Angiotensin inhibition stimulates PPARgamma and the release of visfatin.

BACKGROUND: Angiotensin converting enzyme inhibitors (ACE-I) and angiotensin receptor blockers (ARB) exhibit beneficial antidiabetic effects in patients with type 2 diabetes independent of their blood pressure-lowering effects. Some antidiabetic properties of ARB and ACE-I might by exerted by activation of peroxisome proliferator-activated receptor gamma (PPARgamma). However, it is not clear whether this action is drug specific. MATERIALS AND METHODS: The binding affinity of telmisartan, valsartan, lisinopril, rosiglitazone and angiotensin II to PPARgamma was assessed in a cell-free assay system. PPARgamma signalling was studied in isolated skeletal muscle cells using Western blot analysis of phosphorylated protein kinase B (pAKT) and phosphorylated insulin like growth factor-1 receptor (pILGF-1R). Further, the ability of the drugs under study to stimulate the release of the adipocytokine visfatin was investigated in isolated human adipocytes, skeletal muscle cells, and umbilical vein endothelial cells (HUVEC). RESULTS: The binding affinity to PPARgamma was highest for telmisartan with a half-maximal effective concentration of 463 nM, followed by lisinopril (2.9 microM) and valsartan (6.2 microM). In skeletal muscle cells phosphorylation of ILGF-1R was 2-fold increased after incubation with telmisartan or valsartan and 1.7-fold with lisinopril. pAKT expression was enhanced after incubation with telmisartan, valsartan and with lisinopril. The release of visfatin from adipocytes was 1.6-fold increased after treatment with lisinopril and about 2.0-fold increased with telmisartan and valsartan. Similar results were obtained in skeletal muscle cells and HUVEC. CONCLUSIONS: Our data confirm agonism of telmisartan, valsartan and lisinopril on PPARgamma. Pharmacokinetic differences may explain different potencies of PPARgamma stimulation by drugs acting on the renin-angiotensin system in clinical settings.

Pioglitazone does not affect vascular or inflammatory responses after endotoxemia in humans.

PPARgamma agonists have been proposed to exert more than metabolic benefits, particularly by anti-inflammatory mechanisms. We hypothesized that pioglitazone might modulate inflammatory and vascular responses to lipopolysaccharide (LPS). In a placebo-controlled parallel-group study in 18 healthy male subjects, the E. coli endotoxin model of inflammation (20 IU/kg i. v.) was employed to test the effect of 60 mg pioglitazone over nine days on inflammatory cytokines. Macrovascular function and microvascular blood flow were assessed by brachial artery ultrasound and retinal blood flow parameters, respectively. Pioglitazone increased brachial artery diameter by 5.6% but had no effect on other outcome parameters under resting conditions. LPS increased cytokine levels to peak concentrations of 91.3+/-22.5 ng/ml (IL-6), 261.4+/-60.0 ng/ml (TNFalpha), and 524.5+/-15.3 ng/ml (VCAM-1). The endotoxin caused microvascular vasodilation and increased retinal white blood cell flux, while baseline brachial artery diameter remained unchanged. Pioglitazone had no effect on inflammatory cytokine or adhesion molecule release but mitigated LPS-induced hypotension (p<0.05). Neither brachial artery function nor microvascular blood flow was altered by pioglitazone. In conclusion, acute immune reactions to LPS are not affected by pioglitazone, which exerts subtle vascular effects alone and during endotoxemia. The anti-inflammatory properties of short-term pioglitazone to endotoxins in healthy subjects are therefore limited.

Asymmetrical dimethylarginine is related to renal function, chronic inflammation and macroangiopathy in patients with Type 2 diabetes and albuminuria.

AIMS: Patients with Type 2 diabetes mellitus (T2DM) and micro- and macroalbuminuria are at increased cardiovascular risk. The endogenous nitric oxide synthase inhibitor asymmetrical dimethylarginine (ADMA) is increased in renal failure and could promote atherosclerosis. To determine the relationship between ADMA, renal albumin excretion rate (AER) and cardiovascular risk, we studied 103 T2DM patients. METHODS: ADMA, symmetrical dimethylarginine (SDMA) and L-arginine were determined by high-performance liquid chromatography in plasma from 36 normo-, 40 micro- and 27 macroalbuminuric patients with T2DM (age 64 +/- 11 years; 38 women) who had comparable age, sex and metabolic parameters. Forty-six patients had macrovascular disease (MVD). RESULTS: ADMA was significantly increased in patients with micro- and macroalbuminuria [median 0.61 (interquartile range 0.55-0.70) micromol/l and 0.62 (0.50-0.79) micromol/l, respectively] compared with those with normoalbuminuria [0.55 (0.48-0.63) micromol/l; both P < 0.05]. SDMA was elevated in micro- and macroalbuminuria [0.57 (0.42-0.80) micromol/l and 0.64 (0.50-0.96) micromol/l] compared with normoalbuminuric subjects [0.44 (0.37-0.53) micromol/l; both P < 0.01]. Patients with increased AER and MVD had higher ADMA and SDMA compared with those without MVD (both P < 0.001). L-arginine was comparable between all groups. ADMA correlated significantly with high-sensitivity C-reactive protein (hsCRP) and glomerular filtration rate (GFR) but not with the extent of albumin excretion, body mass index, fasting glucose, HbA(1c) or plasma lipids. CONCLUSIONS: Increased ADMA in T2DM patients with albuminuria is linked to cardiovascular disease and is associated with renal dysfunction and subclinical inflammation.

C-reactive protein is expressed and secreted by peripheral blood mononuclear cells.

C-reactive protein (CRP) protects against bacterial pathogens and is a predictor of cardiovascular events. CRP is produced by vascular and organ-specific cells but the generation of CRP from peripheral blood mononuclear cells (PBMC) is poorly established. In a randomized, double-blind, placebo-controlled, two-way cross-over trial six healthy volunteers received a bolus infusion of 20 IU/kg Escherichia coli endotoxin [lipopolysaccharide (LPS)] or placebo. Intracellular CRP protein and CRP secretion of peripheral blood mononuclear cells (PBMC) was measured at baseline and 6 h after LPS by flow cytometry and enzyme-linked immubosorbent assay (ELISA), respectively. CRP mRNA expression was determined by real-time polymerase chain reaction (PCR). Regulation of the expression pathway was assessed using specific inhibitors in vitro. Small amounts of CRP protein and mRNA were detectable in PBMC, which were up-regulated between two- and eightfold by endotoxaemia in vivo. Augmented expression and release of CRP by LPS was consistent in PBMC cell culture experiments. LPS, interleukin (IL)-1, IL-6 and tumour necrosis factor (TNF)-alpha increased and IL-10 reduced CRP expression in PBMC. Toll-like receptor (TLR)-4, nuclear factor (NF)-kappaB and protein kinase C (PKC) activation were identified as intracellular signal transduction pathways of LPS-induced CRP expression. Constitutive CRP expression and release in PBMC is enhanced by inflammatory stimuli in vivo and in vitro. LPS might induce CRP generation via activation of TLR-4, NF-kappaB and PKC.

The release of the adipocytokine visfatin is regulated by glucose and insulin.

AIMS/HYPOTHESIS: The novel insulin-mimetic adipocytokine visfatin has been linked to the metabolic syndrome, but its regulation has not been characterised to date. Since insulin-mimetic actions of visfatin may be part of the feedback regulation of glucose homeostasis, we hypothesised that visfatin concentrations are influenced by glucose or insulin blood levels in humans. SUBJECTS, MATERIALS AND METHODS: In this randomised, double-blind, placebo-controlled crossover study, nine healthy male subjects (age 26+/-6 years) attended three different study days. On each day, systemic glucose concentrations of 5.0, 8.3 and 11.1 mmol/l were attained by stepwise increases in i.v. infusions of glucose, representing fasting and postprandial conditions. Visfatin plasma concentrations were studied during concomitant exogenous hyperinsulinaemia, inhibition of endogenous insulin production by somatostatin infusion, and placebo time control. Additionally, human adipocytes were cultured to study visfatin release and mRNA expression in vitro. RESULTS: Glucose concentrations of 8.3 and 11.1 mmol/l increased circulating visfatin from baseline concentrations of 0.5+/-0.0 ng/ml to 0.9+/-0.1 and 2.1+/-0.3 ng/ml, respectively (p<0.01). Glucose-induced elevation of visfatin was prevented by co-infusion of insulin or somatostatin (p<0.05). Cultured subcutaneous and visceral adipocytes released an equivalent amount of visfatin upon glucose-concentration- and time-dependent stimulation. Visfatin secretion involved the phosphatidylinositol 3-kinase (PI3-kinase) and protein kinase B (AKT) pathways. The mRNA expression pattern of visfatin was consistent with this altered protein release. CONCLUSIONS/INTERPRETATION: Circulating visfatin concentrations are increased by hyperglycaemia. This effect is suppressed by exogenous hyperinsulinaemia or somatostatin infusion. Glucose signalling for visfatin release in adipocytes involves the PI3-kinase/AKT pathway.

Marked increase in vascular endothelial growth factor concentrations during Escherichia coli endotoxin-induced acute inflammation in humans.

BACKGROUND: Bacterial endotoxins can induce the synthesis and release of vascular endothelial growth factor (VEGF), which may alter vascular permeability and cause vascular leakage. MATERIALS AND METHODS: The effect of acute systemic inflammation on VEGF concentration was measured in healthy males after an intravenous bolus infusion of Escherichia coli endotoxin (lipopolysaccharide, LPS, 20 IU kg-1) in a double-blind, placebo-controlled parallel group study. LPS administration was followed by an infusion of lepirudin (bolus 0.1 mg kg-1, continuous infusion of 0.1 mg kg-1 h-1, n = 12) or saline (n = 12). RESULTS: Plasma VEGF increased from a mean of 15.1 pg mL-1 to 74.6 pg mL-1 5 h after LPS (P < 0.003). Body temperature, pulse rate, leukcytes, prothrombin fragment 1 + 2 (F1 + 2) and lactoferrin increased and platelets decreased after LPS (P < 0.05). The LPS-induced increase in VEGF was paralleled by the neutrophil cell degranulation marker lactoferrin but not by F1 + 2, and was not affected by lepirudin, which blunted F1 + 2 formation (P < 0.05). CONCLUSIONS: Inflammation-induced activation of leukcytes rather than platelets plays a role in the marked increase in VEGF, which cannot be abrogated by antithrombotic therapy.

Homocysteine promotes the LDL oxidase activity of ceruloplasmin.

Ceruloplasmin (CP) oxidises low density lipoprotein (LDL). The oxidising potential depends on the formation of Cu(+)-CP which is redox-cycled during oxidation. Homocysteine (HCY) reduces free Cu(2+), potentiating its cell-damaging property. We show that HCY enhanced LDL oxidation by CP, but did not activate the LDL oxidising potential of Cu(2+)-diamine oxidase. Selective removal of the redox-active Cu(2+) abolished the LDL oxidase activity of CP. However, HCY partially restored the LDL oxidase activity of redox-copper depleted CP, indicating that the remaining six copper atoms in CP may also be involved in the process. Spectroscopic and oxidation inhibition studies using the Cu(+)-reagent bathocuproine revealed that HCY induced Cu(+)-CP formation, thus promoting its LDL oxidase activity.

Semicarbazide-sensitive amine oxidase catalyzes endothelial cell-mediated low density lipoprotein oxidation.

OBJECTIVE: Deamination products of semicarbazide-sensitive amine oxidases (SSAO), i.e. aldehydes, superoxide and ammonia have been shown to initiate vascular damage. SSAOs are copper-enzymes, present in endothelial (EC), smooth muscle cells (SMC) and in blood. Transition metals ions (Cu, Fe) mediate the oxidative (atherogenic) modification of LDL by SMC and EC. The physiological source of the active metal ions is still under debate. We hypothesize that SSAOs may catalyze LDL oxidation by endothelial cells via enzyme-complexed Cu++. METHODS: EC isolated from human umbilical veins and cultured in 35 mm wells in RPMI-1640 medium were used as LDL oxidation system. RESULTS: Diamine oxidase (DAO), a SSAO which activity is elevated in tissues and sera of diabetic patients, catalyzes the oxidation of LDL by EC. In the presence of purified DAO (0.07 to 70 U/l) LDL oxidation was increased up to 10-fold as measured by thiobarbituric acid reactive substance (TBARS) formation as well as apoprotein modification of LDL. Chemical blockage of the SSAO substrate binding site did not inhibit the catalytic effect of DAO on LDL oxidation. Denaturation of the enzyme did not destroy the ability of the preparation to facilitate LDL oxidation by EC. The potential of the enzyme to catalyze LDL oxidation was not suppressed in the presence of serum. However, selective removing of enzyme-copper completely abolished the ability of the enzyme to trigger cell-mediated LDL oxidation. CONCLUSION: DAO, beside generating angiopathic deamination products, has the potential to act as a pathophysiological catalyst of LDL atherogenic modification by vascular cells.

Decreased serum erythropoietin and its relation to anti-erythropoietin antibodies in anaemia of systemic lupus erythematosus.

OBJECTIVE: This study was performed to assess erythropoietin levels and anti-erythropoietin antibodies in patients with systemic lupus erythematosus (SLE). METHODS: The sera of 100 patients with SLE were investigated for serum erythropoietin levels and the presence of anti-erythropoietin antibodies by ELISA. Routine laboratory parameters such as peripheral blood count, relevant parameters of blood chemistry, and immunological parameters of SLE were recorded. RESULTS: Erythropoietin levels were significantly decreased in SLE patients when related to individual haemoglobin and haematocrit values (P<0.001), suggesting an inadequate erythropoietin response in SLE. Anti-erythropoietin antibodies were found in 46% of SLE patients, and erythropoietin levels (but not haemoglobin or haematocrit values) were significantly decreased in these patients compared with patients without anti-erythropoietin antibodies. Serum erythropoietin concentration as determined by ELISA was reduced in the presence of anti-erythropoietin antibodies. Furthermore, anti-erythropoietin antibodies also correlated with younger age, decreased serum levels of complement factors C3 and C4 and elevated anti-double-stranded DNA antibodies. CONCLUSIONS: We conclude that the anaemia of SLE is characterized by an inadequate erythropoietin response. Anti-erythropoietin antibodies are frequently present in SLE and interfere with the measurement of serum erythropoietin level. However, these antibodies are not associated with increased severity of SLE-associated anaemia.

Genistein prevents the glucose autoxidation mediated atherogenic modification of low density lipoprotein.

Hyperglycemia has been assumed to be responsible for oxidative stress in diabetes. In this respect, glucose autoxidation and advanced glycation end products (AGE) may play a causal role in the etiology of diabetic complications as e.g. atherosclerosis. There is now growing evidence that the oxidative modification of LDL plays a potential role in atherogenesis. Glucose derived oxidants have been shown to peroxidise LDL. In the present study, genistein, a compound derived from soy with a flavonoid chemical structure (4', 5, 7-trihydroxyisoflavone) has been evaluated for its ability to act as an antioxidant against the atherogenic modification of LDL by glucose autoxidation radical products. Daidzein, (4',7-dihydroxyisoflavone) an other phytoestrogen of soy, was tested in parallel. Genistein--in contrast to daidzein--effectively prevented the glucose mediated LDL oxidation as measured by thiobarbituric acid-reactive substance formation (TBARS), alteration in electrophoretic mobility, lipid hydroperoxides and fluorescence quenching of tryptophan residues of the lipoprotein. In addition the potential of glucose-oxidized LDL to increase tissue factor (TF) synthesis human endothelial cells (HUVEC) was completely inhibited when genistein was present during LDL oxidative modification by glucose. Both phytoestrogens did not influence the nonenzymatic protein glycation reaction as measured by the in vitro formation of glycated LDL. As the protective effect of genistein on LDL atherogenic modification was found at glucose/genistein molar ratios which may occur in vivo, our findings support the suggested beneficial action of a soy diet in preventing chronic vascular diseases and early atherogenic events.

Characterization of (123)I-vascular endothelial growth factor-binding sites expressed on human tumour cells: possible implication for tumour scintigraphy.

To explore the possibility of vascular endothelial growth factor (VEGF) receptor scintigraphy of primary tumours and their metastases, we analysed the binding properties of (123)I-labelled VEGF(165) ((123)I-VEGF(165)) and (123)I-VEGF(121) to human umbilical vein endothelial cells (HUVECs), several human tumour cell lines (HMC-1, A431, KU812, U937, HEP-1, HEP-G2, HEP-3B and Raji), a variety of primary human tumours (n = 40) and some adjacent non-neoplastic tissues as well as normal human peripheral blood cells in vitro. Two classes of high-affinity (123)I-VEGF(165)-binding site were found on the cell surface of HUVECs. In contrast, one class of high-affinity binding sites for (123)I-VEGF(165) was found on HMC-1, A431, HEP-1, HEP-G2, HEP-3B and U937 cells as well as many primary tumours. For (123)I-VEGF(121), a single class of high-affinity binding site was found on certain cell lines (HUVEC, HEP-1 and HMC-1) and distinct primary tumours (primary melanomas, ductal breast cancers and ovarian carcinomas as well as meningiomas). Tumour cells expressed significantly higher numbers of VEGF receptors compared with normal peripheral blood cells and adjacent non-neoplastic tissues. Immunohistochemical staining revealed that the VEGF receptor Flk-1 is expressed to a much higher extent within malignant tissues compared with neighbouring non-neoplastic cells. We observed significantly greater specific binding of (123)I-VEGF(165) and (123)I-VEGF(121) to a variety of human tumour cells/tissues compared with the corresponding normal tissues or normal peripheral blood cells. In comparison with (123)I-VEGF(121), (123)I-VEGF(165) bound to a higher number of different tumour cell types with a higher capacity. Thus, (123)I-VEGF(165) may be a potentially useful tracer for in vivo imaging of solid tumours.

Effect of intradermal tumor necrosis factor-alpha-induced inflammation on coagulation factors in dermal vessel endothelium. An in vivo study of human skin biopsies.

Inflammatory mediators were shown to exert procoagulant effects on cultured human endothelial cells (EC). In the present study the effect of intradermal application of tumor necrosis factor-alpha (TNF-alpha) on the expression of factors involved in regulation of coagulation at the EC surface, i.e. tissue factor (TF), thrombomodulin (TM) and tissue factor pathway inhibitor (TFPI) was studied in humans in vivo. The endothelial expression of these factors was evaluated immunohistochemically in biopsies taken after intradermal application of 5000 U TNF-alpha in 8 healthy volunteers. After 6 and 22 h biopsies were taken from the injection sites. At TNF-alpha injected sites typical inflammatory changes. e.g. EC upregulation of adhesion molecules and accumulation of leukocytes were detected. In parallel we could document EC expression of TF, downregulation of TM and depletion of tissue factor pathway inhibitor (TFPI) in inflamed areas. Early depletion of endothelial IkappaB alpha at the site of inflammation after application of TNF-alpha points to an activation of the NF-kappaB pathway. Our data suggest that, as shown in in vitro experiments, TNF-alpha activates the NF-kappaB pathway and induces specific procoagulant changes of EC due to expression of TF, down-regulation of TM and depletion of TFPI in vivo in humans. This procoagulant shift in the haemostatic balance on the cell surface, caused by TNF-alpha-induced inflammation, is likely to contribute to thrombosis associated with tissue inflammation in humans.

p-Hydroxyphenylacetaldehyde, the major product of tyrosine oxidation by the activated myeloperoxidase system can act as an antioxidant in LDL.

The oxidative modification of low density lipoprotein (LDL) may play a significant role in atherogenesis. HOCl generated by the myeloperoxidase/H2O2/Cl- system of activated neutrophils may be operative in vivo making LDL atherogenic. Tyrosine has been found to be oxidized by HOCl to p-hydroxyphenylacetaldehyde (p-HA) capable of modifying phospholipid amino groups in LDL. As an amphiphatic phenolic compound, p-HA may have the potential to act as an antioxidant in the lipid phase of LDL. The present results show that (a) tyrosine exerts a protective effect on LDL modification by HOCl, (b) p-HA could act as antioxidant associated with the lipoprotein preventing cell- and transition metal ion-mediated LDL oxidation and (c) p-HA was able to scavenge free radicals.

Glucose and insulin exert additive ocular and renal vasodilator effects on healthy humans.

AIMS/HYPOTHESIS: There is evidence that insulin and glucose cause renal and ocular vasodilation. There is, however, currently no data on the effect of combined hyperglycaemia and hyperinsulinaemia on the renal and ocular blood flow seen in diabetic patients on insulin therapy. METHODS: We carried out two different 3-way crossover studies in healthy subjects (each, n = 9). In study one, hyperglycaemic clamps (5.6 mmol/l, 11.1 mmol/ 1, 16.7 mmol/l) were carried out during placebo or insulin (dose 1: 1 mU/kg/min; dose 2: 2 mU/kg/min) infusion. The second study was identical but endogenous insulin secretion was blocked with somatostatin. The renal plasma flow, glomerular filtration rate and pulsatile choroidal blood flow were measured using the paraaminohippurate method, the inulin method and a laser interferometric measurement of fundus pulsation amplitude, respectively. RESULTS: Insulin increased renal plasma flow and fundus pulsation amplitude but not the glomerular filtration rate. Hyperglycaemia increased all the renal and ocular parameters studied. Haemodynamic effects of glucose and insulin were additive when somatostatin was co-administered but not under basal conditions. CONCLUSIONS/INTERPRETATION: Glucose and insulin can exert additive vasodilator properties on renal and ocular circulation. To find out whether this observation is related to the increased regional perfusion in diabetes longitudinal studies on patients with Type I (insulin-dependent) diabetes mellitus are needed.

Homozygosity for the C-->T polymorphism at nucleotide 46 in the 5' untranslated region of the factor XII gene protects from development of acute coronary syndrome.

Recently, a C-->T polymorphism at nucleotide 46 in the 5'-untranslated region of the factor XII (FXII) gene was shown to be associated with lower levels of FXII. To study the impact of this polymorphism on the development of an acute coronary syndrome (ACS), we compared 303 patients with ACS and 227 patients with stable coronary artery disease (CAD). In the latter group, 54.2% of individuals carried wild-type FXII:46C, 37.9% were heterozygous FXII:C46T and 7.9% were homozygous for FXII:46T. In contrast, in the ACS group (n = 303), 54.1% were wild-type FXII:46C, 42.6% were heterozygous FXII:C46T and only 3.3% carried the homozygous FXII:46T genotype. The 2.5-fold lower prevalence of the FXII:46T genotype in patients with ACS could indicate a protective effect on the development of ACS (odds ratio = 0.4, 95% CI 0.1-0.9) in patients with pre-existing CAD.